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WO2001042190A1 - Method for the stereoselective synthesis of cyclic amino acids - Google Patents

Method for the stereoselective synthesis of cyclic amino acids Download PDF

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Publication number
WO2001042190A1
WO2001042190A1 PCT/US2000/032570 US0032570W WO0142190A1 WO 2001042190 A1 WO2001042190 A1 WO 2001042190A1 US 0032570 W US0032570 W US 0032570W WO 0142190 A1 WO0142190 A1 WO 0142190A1
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Prior art keywords
formula
produce
mixture
product
stirring
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PCT/US2000/032570
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French (fr)
Inventor
Justin Stephen Bryans
David Clive Blakemore
Sophie Caroline Williams
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Warner Lambert Co LLC
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Warner Lambert Co LLC
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Priority to JP2001543492A priority Critical patent/JP2003516378A/en
Priority to EP00980881A priority patent/EP1237847B1/en
Priority to CA002392761A priority patent/CA2392761A1/en
Priority to HU0203812A priority patent/HUP0203812A3/en
Priority to MXPA02004829A priority patent/MXPA02004829A/en
Priority to KR1020027007280A priority patent/KR20020060988A/en
Priority to US10/149,160 priority patent/US6864390B2/en
Priority to PL00355787A priority patent/PL355787A1/en
Priority to SI200030868T priority patent/SI1237847T1/en
Priority to AU18084/01A priority patent/AU1808401A/en
Priority to IL14957500A priority patent/IL149575A0/en
Priority to BR0016201-9A priority patent/BR0016201A/en
Priority to EA200200463A priority patent/EA004984B1/en
Priority to DE60028076T priority patent/DE60028076T2/en
Publication of WO2001042190A1 publication Critical patent/WO2001042190A1/en
Anticipated expiration legal-status Critical
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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C271/00—Derivatives of carbamic acids, i.e. compounds containing any of the groups, the nitrogen atom not being part of nitro or nitroso groups
    • C07C271/06—Esters of carbamic acids
    • C07C271/08—Esters of carbamic acids having oxygen atoms of carbamate groups bound to acyclic carbon atoms
    • C07C271/10—Esters of carbamic acids having oxygen atoms of carbamate groups bound to acyclic carbon atoms with the nitrogen atoms of the carbamate groups bound to hydrogen atoms or to acyclic carbon atoms
    • C07C271/12—Esters of carbamic acids having oxygen atoms of carbamate groups bound to acyclic carbon atoms with the nitrogen atoms of the carbamate groups bound to hydrogen atoms or to acyclic carbon atoms to hydrogen atoms or to carbon atoms of unsubstituted hydrocarbon radicals
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
    • A61P25/00—Drugs for disorders of the nervous system
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
    • A61P25/00—Drugs for disorders of the nervous system
    • A61P25/08—Antiepileptics; Anticonvulsants
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C227/00—Preparation of compounds containing amino and carboxyl groups bound to the same carbon skeleton
    • C07C227/30—Preparation of optical isomers
    • C07C227/32—Preparation of optical isomers by stereospecific synthesis
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C229/00—Compounds containing amino and carboxyl groups bound to the same carbon skeleton
    • C07C229/02—Compounds containing amino and carboxyl groups bound to the same carbon skeleton having amino and carboxyl groups bound to acyclic carbon atoms of the same carbon skeleton
    • C07C229/28—Compounds containing amino and carboxyl groups bound to the same carbon skeleton having amino and carboxyl groups bound to acyclic carbon atoms of the same carbon skeleton the carbon skeleton being saturated and containing rings
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C255/00—Carboxylic acid nitriles
    • C07C255/01—Carboxylic acid nitriles having cyano groups bound to acyclic carbon atoms
    • C07C255/31—Carboxylic acid nitriles having cyano groups bound to acyclic carbon atoms having cyano groups bound to acyclic carbon atoms of a carbon skeleton containing rings other than six-membered aromatic rings
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C255/00—Carboxylic acid nitriles
    • C07C255/01—Carboxylic acid nitriles having cyano groups bound to acyclic carbon atoms
    • C07C255/32—Carboxylic acid nitriles having cyano groups bound to acyclic carbon atoms having cyano groups bound to acyclic carbon atoms of a carbon skeleton containing at least one six-membered aromatic ring
    • C07C255/41—Carboxylic acid nitriles having cyano groups bound to acyclic carbon atoms having cyano groups bound to acyclic carbon atoms of a carbon skeleton containing at least one six-membered aromatic ring the carbon skeleton being further substituted by carboxyl groups, other than cyano groups
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C265/00—Derivatives of isocyanic acid
    • C07C265/02—Derivatives of isocyanic acid having isocyanate groups bound to acyclic carbon atoms
    • C07C265/06—Derivatives of isocyanic acid having isocyanate groups bound to acyclic carbon atoms of an unsaturated carbon skeleton
    • C07C265/08—Derivatives of isocyanic acid having isocyanate groups bound to acyclic carbon atoms of an unsaturated carbon skeleton the carbon skeleton containing rings
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
    • C07C51/08—Preparation of carboxylic acids or their salts, halides or anhydrides from nitriles
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
    • C07C51/41—Preparation of salts of carboxylic acids
    • C07C51/412—Preparation of salts of carboxylic acids by conversion of the acids, their salts, esters or anhydrides with the same carboxylic acid part
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
    • C07C51/42—Separation; Purification; Stabilisation; Use of additives
    • C07C51/43—Separation; Purification; Stabilisation; Use of additives by change of the physical state, e.g. crystallisation
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C69/00—Esters of carboxylic acids; Esters of carbonic or haloformic acids
    • C07C69/608—Esters of carboxylic acids having a carboxyl group bound to an acyclic carbon atom and having a ring other than a six-membered aromatic ring in the acid moiety
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C69/00—Esters of carboxylic acids; Esters of carbonic or haloformic acids
    • C07C69/612—Esters of carboxylic acids having a carboxyl group bound to an acyclic carbon atom and having a six-membered aromatic ring in the acid moiety
    • C07C69/616—Esters of carboxylic acids having a carboxyl group bound to an acyclic carbon atom and having a six-membered aromatic ring in the acid moiety polycyclic
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07B—GENERAL METHODS OF ORGANIC CHEMISTRY; APPARATUS THEREFOR
    • C07B2200/00—Indexing scheme relating to specific properties of organic compounds
    • C07B2200/07—Optical isomers
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C2601/00—Systems containing only non-condensed rings
    • C07C2601/06—Systems containing only non-condensed rings with a five-membered ring
    • C07C2601/08—Systems containing only non-condensed rings with a five-membered ring the ring being saturated

Definitions

  • R] is hydrogen or a lower alkyl radical and n is 4, 5, or 6 are known in
  • the uses disclosed are: protective effect against cramp induced by thiosemicarbazide; protective action against cardiazole cramp; the cerebral diseases, epilepsy, faintness attacks, hypokinesia, and cranial traumas; and improvement in cerebral functions.
  • the compounds are useful in geriatric patients.
  • the patents are hereby inco ⁇ orated by reference.
  • R is hydrogen or a lower alkyl
  • R ⁇ to Rg are each independently selected from hydrogen, straight or branched alkyl of from 1 to 6 carbon atoms, phenyl, benzyl, fluorine, chlorine, bromine, hydroxy, hydroxymethyl, amino, aminomethyl, trifluoromethyl, -CO2H,
  • Ri5 is a straight or branched alkyl of from 1 to 6 carbons, phenyl, or benzyl, and R ⁇ to Rg are not simultaneously hydrogen.
  • Rl is -X(CH 2 ) n Ar
  • R2 is Ar
  • P 1 is -X(CH 2 ) n R8; P is -X(CH 2 ) n Rg, or -XR 9 Y;
  • R3 and R5 are independently hydrogen, Ri 1 , OH, Cj.g alkoxy, S(O) ⁇ R ⁇ ⁇ , N(Rg)2, Br, F, I, Cl, CF3, NHCOR 6 , -Ri 1 CO2R7, -XR9-Y, or -X(CH2) n Rg wherein each methylene group within -X(CH2) n Rg may be unsubstituted or substituted by one or two -(CH2) n Ar groups;
  • R4 is hydrogen, R n , OH, C ⁇ _ 5 alkoxy, S(O) q R ⁇ 1, N(R 6 ) 2 , -X(R ⁇ 1), Br, F, I, Cl, or NHCORg wherein the C1.5 alkoxy may be unsubstituted or substituted by OH, methoxy, or halogen;
  • Rg is independently hydrogen or C1.4 alkyl;
  • R7 is independently hydrogen, C . alkyl, or (CH2) n Ar;
  • Rg is hydrogen, R u , CO2R7, PO 3 H 2 , SO2NR 7 R! ] , NR 7 SO 2 R ⁇ 1 , P(O)(OH)R 7 ,
  • XC 1.5 alkyl RI Q is R ⁇ or R4; R ⁇ ⁇ is C1 _g alkyl, C2-g alkenyl, C2- alkynyl, all of which may be unsubstituted or substituted by one or more OH, CH2OH, N(Rg)2, or halogen; X is (CH 2 ) n , O, NR 6 , or S(O) q ; Y is CH3 or X(CH 2 ) n Ar; Ar is:
  • B is -CH 2 - or -O-;
  • Z ⁇ , ⁇ 2, Z3, and Z4 are independently hydrogen, C1 _g alkyl, C2_ alkenyl,
  • Pi, and P 2 is not NRgRoY; • X is not NRg, and Z3 is not OH or N(Rg)2 in Formula (III);
  • a compound comprised of two or more stereoisomers frequently resides in just one ofthe stereoisomers.
  • the other stereoisomer(s) typically is inactive at best or exhibits undesirable side effects such as, for example, toxicity. Therefore where a compound is comprised of two or more stereoisomers, it is important, and sometimes mandatory, to develop a method of selectively preparing the beneficial stereoisomer in a form that is free from, or almost free from, contamination by the other inactive or harmful stereoisomer(s). However, usually it is very difficult to discover a method for the preparation of a beneficial stereoisomer in a form that is free from, or almost free from, contamination by the other inactive or harmful stereoisomer(s).
  • the instant invention encompasses novel synthetic routes for the preparation of important 3-substituted cyclopentyl-based analogs of gabapentin and pharmaceutically acceptable salts thereof.
  • Gabapentin marketed under the trade name Neurontin® for the treatment of seizure disorders, particularly epilepsy, provides well-known medical benefits to patients in need of such treatment.
  • the instant invention encompasses novel synthetic routes for the preparation of 3-substituted cyclopentyl-based analogs of gabapentin and pharmaceutically acceptable salts thereof that enable the synthesis of each stereoisomer of these analogs with a high degree of stereochemical purity. These routes provide access to pure stereoisomers of Formulas I, II, III, and IV
  • the invention encompasses the key intermediates of formulas (6) and (26). Still further, the invention provides novel synthetic routes for the preparation of compounds of formulas (6) and (26). The routes enable the synthesis of each stereoisomer of compounds of formulas (6) and (26) with a high degree of stereochemical purity. These routes provide access to pure stereoisomers of formulas (6) and (26) wherein R is C]-C ⁇ o alkyl or C3-C10 cycloalkyl.
  • the invention provides a process for the preparation of a compound of Formula I
  • R is C[-C ⁇ Q alkyl or C3-C1 o cycloalkyl, and pharmaceutically acceptable salts thereof, which comprises: a) adding a cyanoacetate of formula (A) is alkyl or benzyl, to a mixture of a chiral cyclopentanone of formula (1)
  • Step b) adding the products of Step b) above to a mixture of a base selected from potassium hydroxide, sodium hydroxide, lithium hydroxide, or cesium hydroxide in a solvent and stirring, and then acidifying to produce the carboxylic acids of formulas (4a) and (4b)
  • Step e) adding the product of Step e) to a mixture of iodomethane, a solvent, and a
  • Step e) or adding the product of Step e) to methanol and an acid to produce the
  • Step f) adding the product of Step f) to a mixture of carbon tetrachloride or ethyl acetate, and acetonitrile, water, sodium periodate, and ruthenium(III) chloride, and stirring to produce the carboxylic acid of formula (8)
  • Step g) adding the product of Step g) to a mixture of a tertiary amine base, a solvent, and diphenylphosphoryl azide (DPP A), and stirring to produce the
  • Step a) adding the product of Step a) above to a mixture of benzylmagnesium chloride, benzylmagnesium bromide, or benzylmagnesium iodide in a solvent selected from tetrahydrofuran, benzene, 1 ,4-dioxane, hexanes, ⁇ -heptane, toluene, diethyl ether, and tert-butyl methyl ether to produce
  • Step b) adding the products of Step b) above to a mixture of a base selected from potassium hydroxide, sodium hydroxide, lithium hydroxide, and cesium hydroxide in a solvent selected from ethylene glycol, 2-methoxyethyl ether, 1 ,4-dioxane, and diethylene glycol, and stirring the mixture, and then acidifying to produce the carboxylic acids of formulas (4a)
  • a base selected from potassium hydroxide, sodium hydroxide, lithium hydroxide, and cesium hydroxide
  • a solvent selected from ethylene glycol, 2-methoxyethyl ether, 1 ,4-dioxane, and diethylene glycol
  • Step b) adding the products of Step b) above to an acid mixture selected from 6-12 M HCl, 12 M H 2 SO 4 , 10%-48% wt/wt hydrobromic acid, and HBr in aqueous acetic acid, and stirring to produce the carboxylic acids of
  • Step d) adding the product of Step d) to a mixture selected from aqueous hydrochloric acid, aqueous sulfuric acid, aqueous acetic acid, hydrochloric acid dissolved in acetic acid, or hydrochloric acid dissolved in acetic acid to which water is added and stirring to produce the carboxylic acid of
  • Step d) partitioning the product of Step d) between a mixture of aqueous hydrochloric acid and a solvent selected from chloroform, dichloromethane, ethyl acetate, ethyl ether, tetrahydrofuran, 1 ,4-dioxane, toluene, and tert-butylmethylether, and drying and evaporating the organic
  • triethylamine triethylamine
  • Step e) or adding the product of Step e) above to a mixture of methanol and concentrated sulphuric acid, concentrated hydrochloric acid, or hydrogen chloride at a temperature of from 0°C to 100°C to produce the ester of
  • Step f) adding the product of Step f) to a mixture of carbon tetrachloride or ethyl acetate, and acetonitrile, water, sodium periodate, and ruthenium(III) chloride, and stirring at a temperature from -40°C to 80°C to produce the
  • R chloroformate or isobutyl chloroformate a base selected from triethylamine and diisopropylethylamine, and a solvent selected from tetrahydrofuran, acetone, and diethyl ether at a temperature of from -40°C to 78°C, followed by adding a solution of sodium azide in water and tetrahydrofuran or acetone, followed by adding toluene or benzene, and
  • Step i) adding the product of Step i) to a mixture of a solvent selected from water, acetic acid, and 1 ,4-dioxane, and aqueous hydrochloric acid at a concentration of from 0.01 M to 12 M, and stirring at a temperature from 0°C to 115°C to produce a compound of formula la
  • R acceptable salt by known means. More preferred is a process for the preparation of a compound of Formula I wherein R is Ci -C J Q alkyl or C3-C10 cycloalkyl, and pharmaceutically acceptable salts thereof, which comprises: a) adding a cyanoacetate of formula (A) , wherein R ⁇ is
  • Step b) adding the products of Step b) above to a mixture of potassium hydroxide in ethylene glycol, and heating the mixture at 100°C to 200°C, and then acidifying to produce the hydrolysis products of
  • Step d) adding the product of Step d) to aqueous hydrochloric acid and stirring to
  • Step e) adding the product of Step e) to a mixture of iodomethane, dichloromethane, and l,8-diazabicyclo[5.4.0]undec-7-ene (DBU), and stirring to produce the ester of formula (7) ; or addin
  • Step f) adding the product of Step f) to a mixture of carbon tetrachloride or ethyl acetate, and acetonitrile, water, sodium periodate, and ruthenium(III) chloride, and stirring to produce the carboxylic acid of formula (8)
  • Step i) adding the product of Step i) to a mixture of 1 ,4-dioxane and aqueous hydrochloric acid at a concentration of 6 M, and stirring to produce a
  • R acceptable salt by known means. Also preferred is a process for the preparation of a compound of Formula I as described above, further characterized in that the intermediate
  • product (9) formed is reacted, without isolation, with
  • the invention provides a process for the preparation of a compound of Formula II
  • R is Ci -CI Q alkyl or C3-C10 cycloalkyl, and pharmaceutically acceptable salts thereof, which comprises: a) adding a cyanoacetate of formula (A) NC ⁇ / - L> Kj ⁇ wn erein R ⁇ is alkyl or benzyl, to a mixture of a chiral cyclopentanone of
  • Step b) adding the products of Step b) above to a mixture of a base selected from potassium hydroxide, sodium hydroxide, lithium hydroxide, and cesium hydroxide and a solvent, and stirring, and then acidifying to produce the
  • Step e) adding the product of Step e) to a mixture of a tertiary amine base, a solvent, and diphenylphosphoryl azide (DPP A), and stirring to produce the
  • Step f) adding the product of Step f) to a mixture of a solvent and methanol, and
  • Step g) adding the product of Step g) to a mixture of carbon tetrachloride or ethyl acetate, and acetonitrile, water, sodium periodate, and ruthenium(III) chloride, and stirring to produce the carboxylic acid of
  • Step b) adding the product of Step a) above to a mixture of benzylmagnesium chloride, benzylmagnesium bromide, or benzylmagnesium iodide in a solvent selected from tetrahydrofuran, benzene, 1 ,4-dioxane, hexanes, ⁇ -heptane, toluene, diethyl ether, and tert-butyl methyl ether to produce the addition products of formulas (3 a) and
  • Step b) adding the products of Step b) above to a mixture of a base selected from potassium hydroxide, sodium hydroxide, lithium hydroxide, and cesium hydroxide in a solvent selected from ethylene glycol, 2-methoxyethyl ether, 1,4-dioxane, and diethylene glycol, and stirring the mixture and then acidifying to produce the carboxylic acids of formulas (4a)
  • a base selected from potassium hydroxide, sodium hydroxide, lithium hydroxide, and cesium hydroxide
  • a solvent selected from ethylene glycol, 2-methoxyethyl ether, 1,4-dioxane, and diethylene glycol
  • Step b) adding the products of Step b) above to an acid mixture selected from 6-12 M HCl, 12 M H2SO4, 10%-48% wt/wt hydrobromic acid, and HBr in aqueous acetic acid, and stirring to produce the carboxylic acids of
  • Step c) contacting the products of Step c) above with an amine selected from (S)- ⁇ -mefhyl-benzylamine, (R)- ⁇ -methyl-benzylamine, (R)-(+)-l- (naphthyl)ethylamine, (S)-(+)- 1 -(naphthyl)ethylamine, triethylamine, diisopropylethylamine, dicyclohexylamine, benzylamine, dibenzylamine, morpholine, N-methylmorpholine, piperidine, N-methylpiperidine, and pyridine in a solvent selected from N,N-dimethylformamide, chloroform, benzene,, xylenes, hexanes, acetone, ethanol, methanol, z ' s ⁇ -propanol, diethyl ether, dichloromethane, benzene, toluene,
  • Step d) adding the product of Step d) to a mixture selected from aqueous hydrochloric acid, aqueous sulfuric acid, aqueous acetic acid, hydrochloric acid dissolved in acetic acid, and hydrochloric acid dissolved in acetic acid and water, and stirring to produce the carboxylic acid of formula (6)
  • Step d) partitioning the product of Step d) between a mixture of aqueous hydrochloric acid and a solvent selected from chloroform, dichloromethane, ethyl acetate, ethyl ether, tetrahydrofuran, 1 ,4-dioxane, toluene, and tert-butylmethylether, and drying and evaporating the organic
  • Step e) adding the product of Step e) above to a mixture of a base selected from triethylamine and diisopropylethylamine, a solvent selected from toluene, benzene, xylenes, tetrahydrofuran, diethyl ether and »-heptane, and diphenylphosphoryl azide (DPP A), and stirring at a temperature of from 0°C to 150°C to produce the isocyanate of formula (1 1)
  • Step e) ethyl chloroformate or isobutyl chloroformate and a base selected from triethylamine and diisopropylethylamine, and a solvent selected from tetrahydrofuran, acetone, and diethyl ether at a temperature of from -40°C to 78°C, followed by adding a solution of sodium azide in water and tetrahydrofuran or acetone, followed by adding toluene or benzene, and
  • Step f) adding the product of Step f) to a solvent selected from toluene, benzene, xylenes, and ⁇ -heptane, and methanol, and stirring at a temperature from 0°C to 150°C to produce the carbamate of formula (12)
  • Step g) adding the product of Step g) to a mixture of carbon tetrachloride or ethyl acetate, and acetonitrile, water, sodium periodate, and ruthenium(III) chloride, and stirring at a temperature from -40°C to 80°C to produce the
  • Step h) adding the product of Step h) to a mixture of a solvent selected from water, acetic acid, and 1 ,4-dioxane, and aqueous hydrochloric acid at a concentration of from 0.01 M to 12 M, and stirring at a temperature from 0°C to 115°C to produce a compound of formula Ila
  • Step b) adding the products of Step b) above to a mixture of potassium hydroxide in ethylene glycol, and heating the mixture at 100°C to 200°C, and then acidifying to produce the hydrolysis products of formulas (4a)
  • Step d) adding the product of Step d) to aqueous hydrochloric acid and stirring to
  • Step e) adding the product of Step e) to a mixture of triethylamine, toluene, and diphenylphosphoryl azide (DPP A), and refluxing to produce the isocyanate of formula (1 1) ; or adding the product of
  • Step g) adding the product of Step g) to a mixture of carbon tetrachloride or ethyl acetate, and acetonitrile, water, sodium periodate, and ruthenium(III) chloride, and stirring to produce the carboxylic acid of
  • R acceptable salt by known means. Also preferred is a process for the preparation of a compound of Formula II as described above, further characterized in that the intermediate
  • product (11) formed is further reacted, without isolation, with
  • the invention provides a process for the preparation of a compound of Formula II
  • R wherein R is C ⁇ -C ⁇ Q alkyl or C3-C10 cycloalkyl, and pharmaceutically acceptable salts thereof, which comprises: a) adding a cyanoacetate of formula (A) NC ⁇ /- ⁇ 2 1 , wherein R ⁇ is alkyl or benzyl, to a mixture of a chiral cyclopentanone of formula (1)
  • Step a) adding the product of Step a) above to a mixture of benzylmagnesium chloride, benzylmagnesium bromide, or benzylmagnesium iodide, in a solvent to produce the addition products of formulas (3 a)
  • Step b) adding the products of Step b) above to a mixture of a base selected from potassium hydroxide, sodium hydroxide, lithium hydroxide, and cesium hydroxide, in a solvent, and stirring, and then acidifying to produce the carboxylic acids of formulas (4a) (4b)
  • a base selected from potassium hydroxide, sodium hydroxide, lithium hydroxide, and cesium hydroxide
  • Step g) adding the product of Step g) to a mixture of carbon tetrachloride or ethyl acetate, and acetonitrile, water, sodium periodate, and ruthenium(III) chloride, and stirring to produce the carboxylic acid of formula (16)
  • Step j) adding the product of Step j) to a mixture of a tertiary amine base, a solvent, and diphenylphosphoryl azide (DPP A) is added, and stirring to
  • Step k adding the product of Step k) to a mixture of a solvent and methanol
  • Step b) adding the product of Step a) above to a mixture of benzylmagnesium chloride, benzylmagnesium bromide, or benzylmagnesium iodide in a solvent selected from tetrahydrofuran, benzene, 1 ,4-dioxane, hexanes, 77-heptane, toluene, diethyl ether, and tert-butyl methyl ether to produce the addition products of formulas (3 a) and (3b)
  • Step b) adding the products of Step b) above to a mixture of a base selected from potassium hydroxide, sodium hydroxide, lithium hydroxide, and cesium hydroxide in a solvent selected from ethylene glycol, 2-methoxyethyl ether, 1 ,4-dioxane, and diethylene glycol, and stirring the mixture and then acidifying to produce the carboxylic acids of formulas (4a)
  • a base selected from potassium hydroxide, sodium hydroxide, lithium hydroxide, and cesium hydroxide
  • a solvent selected from ethylene glycol, 2-methoxyethyl ether, 1 ,4-dioxane, and diethylene glycol
  • Step b) adding the products of Step b) above to an acid mixture selected from 6-12 M HCl, 12 M H2SO4, 10%-48% wt/wt hydrobromic acid, and HBr in aqueous acetic acid, and stirring to produce the carboxylic acids of
  • Step c) contacting the products of Step c) above with an amine selected from (S)- ⁇ -methyl-benzylamine, (R)- ⁇ -methyl-benzylamine, (R)-(+)-l- (naphthyl)ethylamine, (S)-(+)-l -(naphthyl)ethylamine, triethylamine, diisopropylethylamine, dicyclohexylamine, benzylamine, dibenzylamine, morpholine, N-methylmorpholine, piperidine, N-methylpiperidine, and pyridine in a solvent selected from N,N-dimethylformamide, chloroform, benzene, xylenes, hexanes, acetone, ethanol, methanol, z s -propanol, diethyl ether, dichloromethane, benzene, toluene, n-pentane,
  • Step d) adding the product of Step d) to a mixture selected from aqueous hydrochloric acid, aqueous sulfuric acid, aqueous acetic acid, hydrochloric acid dissolved in acetic acid, or hydrochloric acid dissolved in acetic acid and water, and stirring to produce the carboxylic acid of formula (6)
  • Step d) partitioning the product of Step d) between a mixture of aqueous hydrochloric acid and a solvent selected from chloroform, dichloromethane, ethyl acetate, ethyl ether, tetrahydrofuran, 1,4-dioxane, toluene, and tert-butylmethylether, and drying and evaporating the organic
  • Step e adding oxalyl chloride to a mixture ofthe product of Step e), a solvent selected from dichloromethane, chloroform, ethyl ether, toluene, and tert- butyl methyl ether, and 0.01 to 10 mole percent of N,N- dimethylformamide (DMF), and stirring at a temperature from -40°C to
  • Step f) adding the product of Step f) to a mixture of tert-butyl alcohol, a solvent selected from dichloromethane, chloroform, ethyl ether, toluene, and tert- butyl methyl ether, and NN-diisopropylethylamine (DIPEA) or triethylamine, and stirring at a temperature from -40°C to 110°C to
  • Step g) adding the product of Step g) to a mixture of carbon tetrachloride or ethyl acetate, and acetonitrile, water, sodium periodate, and rufhenium(III) chloride, and stirring at a temperature from -40°C to 80°C to produce the
  • Step h) adding the product of Step h) to a solvent selected from toluene, benzene, xylenes, and / ⁇ -heptane, methanol, and (trimethylsilyl)diazomethane, and stirring at a temperature from 0°C to 150°C to produce the bis ester of
  • R j) adding hydrochloric acid or trifluoroacetic acid (TFA) to a mixture ofthe product from Step i) and a solvent selected from dichloromethane, chloroform, 1 ,4-dioxane, tetrahydrofuran, ethyl ether, and tert-butyl methyl ether, and stirring at a temperature from -40°C to 110°C to produce
  • TFA trifluoroacetic acid
  • Step j) adding the product of Step j) to a mixture of a base selected from triethylamine and diisopropylethylamine, a solvent selected from toluene, benzene, xylenes, and «-heptane, and diphenylphosphoryl azide (DPPA), and stirring at a temperature from 0°C to 150°C to produce the isocyanate
  • a base selected from triethylamine and diisopropylethylamine
  • a solvent selected from toluene, benzene, xylenes, and «-heptane
  • DPPA diphenylphosphoryl azide
  • Step k 1) adding the product of Step k) to a mixture of a solvent selected from toluene, benzene, xylenes, and rc-heptane, and methanol, and stirring at a temperature from 0°C to 150°C to produce the carbamate of formula (20)
  • Step 1) adding the product of Step 1) to a mixture of a solvent selected from water, acetic acid, and 1 ,4-dioxane, and aqueous hydrochloric acid at a concentration of from 0.01 M to 12 M, and stirring at a temperature from 0°C to 115°C to produce a compound of formula Ila
  • Step d) adding the product of Step d) to aqueous hydrochloric acid and stirring to
  • Step f) adding the product of Step f) to a mixture of tert-butyl alcohol, dichloromethane, and NN-diisopropylethylamine (DIPEA), and stirring to
  • Step j) adding the product of Step j) to a mixture of triethylamine, toluene, and diphenylphosphoryl azide (DPP A), and refluxing to produce the
  • Step 1) adding the product of Step 1) to a mixture of 1 ,4-dioxane and aqueous hydrochloric acid at a concentration of 6 M, and stirring to produce a
  • product (19) formed is further reacted, without isolation, with
  • R is Ci -C ⁇ Q alkyl or C3-C1 o cycloalkyl, and pharmaceutically acceptable salts thereof, which comprises: a) adding a cyanoacetate of formula (A) C ⁇ / ⁇ 2 1 , wherein R is alkyl or benzyl, to a mixture of a chiral cyclopentanone of formula (21)
  • Step b) adding the products of Step b) above to a mixture of a base selected from potassium hydroxide, sodium hydroxide, lithium hydroxide, and cesium hydroxide, in a solvent, and stirring, and then acidifying to produce the
  • Step e) adding the product of Step e) to a mixture of iodomethane, a solvent, and l,8-diazabicyclo[5.4.0]undec-7-ene (DBU), and stirring to produce the
  • Step f) adding the product of Step f) to a mixture of carbon tetrachloride or ethyl acetate, and acetonitrile, water, sodium periodate, and ruthenium(III) chloride, and stirring to produce the carboxylic acid of formula (28)
  • Step g) adding the product of Step g) to a mixture of a tertiary amine base, a solvent, and diphenylphosphoryl azide (DPP A), and stirring to produce the
  • Step i) adding the product of Step i) to a mixture of a solvent and aqueous hydrochloric acid, and stirring to produce a compound of formula (Ilia)
  • the invention provides a process for the preparation of a compound of Formula IV
  • R is C]-C ⁇ Q alkyl or C3-C10 cycloalkyl, and pharmaceutically acceptable salts thereof, which comprises: a) adding a cyanoacetate of formula (A) NC ⁇ ⁇ / ⁇ 2 1 , wherein R ⁇ is alkyl or benzyl, to a mixture of a chiral cyclopentanone of formula (21)
  • Step b) adding the product of Step a) above to a mixture of benzylmagnesium chloride or benzylmagnesium iodide, in a solvent to produce the addition
  • Step b) adding the products of Step b) above to a mixture of a base selected from potassium hydroxide, sodium hydroxide, lithium hydroxide, and cesium hydroxide, in a solvent, and stirring, and then acidifying to produce the
  • Step e) adding the product of Step e) to a mixture of a tertiary amine base, a solvent, and diphenylphosphoryl azide (DPP A) is added, and stirring to
  • Step f) adding the product of Step f) to a mixture of a solvent and methanol, and
  • Step g) adding the product of Step g) to a mixture of carbon tetrachloride or ethyl acetate, and acetonitrile, water, sodium periodate, and ruthenium(III) chloride, and stirring to produce the carboxylic acid of formula (33)
  • Step e) adding the product of Step e) to a mixture of a base selected from triethylamine or diisopropylethylamine and a solvent selected from toluene, benzene, xylenes, or ⁇ -heptane to which diphenylphosphoryl azide (DPP A) was added, and stirring at a temperature from 0°C to 150°C to produce the isocyanate of formula (31); g) adding the product of Step f) to a solvent selected from toluene, benzene, xylenes, or r ⁇ -heptane to which methanol was added and stirring at a temperature from 0°C to 150°C to produce the carbamate of formula (32); h) adding the product of Step g) to a mixture of carbon tetrachloride and acetonitrile to which water, sodium periodate, and ruthenium(III) chloride were added, and stirring at a temperature from -40°
  • R is Ci -Ci Q alkyl or C3-C10 cycloalkyl, and pharmaceutically acceptable salts thereof, which comprises: a) adding ethyl cyanoacetate to a mixture of a chiral cyclopentanone of formula (21) in toluene to which acetic acid and ammonium acetate were added, and heating the mixture at reflux to produce the alkene of formula (22); b) adding the product of Step a) above to a mixture of benzylmagnesium chloride in dry tetrahydrofuran at -100°C to -20°C to produce the addition products of formulas (23a) and (23b); c) adding the products of Step b) above to a mixture of potassium hydroxide in ethylene glycol, and heating the mixture at 100°C to 200°C to produce the hydrolysis products of formulas (24a) and (24b); d) contacting the products of Step c) above with (R)- ⁇ -methyl-
  • the invention provides a process for the preparation of a compound of Formula IV
  • R is Ci -Ci Q alkyl or C3-C1 Q cycloalkyl, and pharmaceutically acceptable salts thereof, which comprises: a) adding a cyanoacetate of formula (A) NC ⁇ / ⁇ - ⁇ 1 , wherein R ⁇ is alkyl or benzyl, to a mixture of a chiral cyclopentanone of formula (21) , a solvent, a carboxylic acid, and a Knoevenagel reaction
  • Step b) adding the product of Step a) above to a mixture of benzylmagnesium chloride or benzylmagnesium iodide, in a solvent to produce the addition
  • Step b) adding the products of Step b) above to a mixture of a base selected from potassium hydroxide, sodium hydroxide, lithium hydroxide, and cesium hydroxide, in a solvent, and stirring, and then acidifying to produce the
  • Step g) adding the product of Step g) to a mixture of carbon tetrachloride or ethyl acetate, and acetonitrile, water, sodium periodate, and ruthenium(III) chloride, and stirring to produce the carboxylic acid of formula (36)
  • Step h) adding the product of Step h) to a mixture of a solvent, methanol, and (trimethylsilyl)diazomethane, and stirring to produce the bis ester of
  • Step j) adding the product of Step j) to a mixture of a tertiary amine base, a solvent, and diphenylphosphoryl azide (DPP A), and stirring to produce the
  • Step k 1) adding the product of Step k) to a mixture of a solvent and methanol, and
  • Step k) 1) adding the product of Step k) to a solvent selected from toluene, benzene, xylenes, or ⁇ -heptane to which methanol was added and stirring at a temperature from 0°C to 150°C to produce the carbamate of formula (40); m) adding the product of Step 1) to a solvent selected from water, acetic acid, or 1 ,4-dioxane to which aqueous hydrochloric acid at a concentration of from
  • product (39) formed is further reacted, without isolation, with
  • the invention provides a process for the preparation of a compound of formula (6)
  • R wherein R is Ci -Ci Q alkyl or C3-C1 Q cycloalkyl, and pharmaceutically acceptable salts thereof, which comprises: a) adding a cyanoacetate of formula (A) NC ⁇ / ⁇ ⁇ 2 1 , wherein R ⁇ is alkyl or benzyl, to a mixture of a chiral cyclopentanone of formula (1)
  • Step b) adding the products of Step b) above to a mixture of a base selected from potassium hydroxide, sodium hydroxide, lithium hydroxide, and cesium hydroxide, and a solvent, and stirring, and then acidifying to produce the carboxylic acids of formulas (4a) and (4b)
  • Step b) adding the product of Step a) above to a mixture of benzylmagnesium chloride, benzylmagnesium bromide, or benzylmagnesium iodide in a solvent selected from tetrahydrofuran, benzene, 1 ,4-dioxane, hexanes, ⁇ -heptane, toluene, diethyl ether, and tert-butyl methyl ether to produce
  • Step b) adding the products of Step b) above to a mixture of a base selected from potassium hydroxide, sodium hydroxide, lithium hydroxide, and cesium hydroxide in a solvent selected from ethylene glycol, 2-methoxyethyl ether, 1 ,4-dioxane, and diethylene glycol, and stirring the mixture, and then acidifying to produce the carboxylic acids of formulas (4a) and (4b) ; 0 r adding the products of
  • Step c) contacting the products of Step c) above with an amine selected from (S)- ⁇ -methyl-benzylamine, (R)- -methyl-benzylamine, (R)-(+)-l- (naphthyl)ethylamine, (S)-(+)- 1 -(naphthyl)ethylamine, triethylamine, diisopropylethylamine, dicyclohexylamine, benzylamine, dibenzylamine, morpholine, N-methylmorpholine, piperidine, N-methylpiperidine, and pyridine in a solvent selected from N,N-dimethylformamide, chloroform, benzene, xylenes, hexanes, acetone, ethanol, methanol, /so-propanol, diethyl ether, dichloromethane, benzene, toluene, n-pentane,
  • Step d) adding the product of Step d) to a mixture selected from aqueous hydrochloric acid, aqueous sulfuric acid, aqueous acetic acid, hydrochloric acid dissolved in acetic acid, and hydrochloric acid dissolved in acetic acid and water, and stirring to produce the carboxylic acid of formula (6)
  • Step d) partitioning the product of Step d) between a mixture of aqueous hydrochloric acid and a solvent selected from chloroform, dichloromethane, ethyl acetate, ethyl ether, tetrahydrofuran, 1 ,4-dioxane, toluene, and tert-butylmethylether, and drying and evaporating the organic
  • Step b) adding the products of Step b) above to a mixture of potassium hydroxide in ethylene glycol, and heating the mixture at 100°C to 200°C, and then acidifying to produce the hydrolysis products of formulas (4a)
  • Step d) adding the product of Step d) to aqueous hydrochloric acid and stirring to
  • the invention provides a process for the preparation of a compound of formula (26)
  • R is C J -CJ O alkyl or C3-C10 cycloalkyl, and pharmaceutically acceptable salts thereof, which comprises: a) adding a cyanoacetate of formula (A) NC ⁇ /' , -' u 2 1 , wherein R ⁇ is alkyl or benzyl, to a mixture of a chiral cyclopentanone of formula (21)
  • Step b) adding the product of Step a) above to a mixture of benzylmagnesium chloride or benzylmagnesium iodide, in a solvent to produce the addition
  • Step b) adding the products of Step b) above to a mixture of a base selected from potassium hydroxide, sodium hydroxide, lithium hydroxide, and cesium hydroxide, and a solvent, and stirring, and then acidifying to produce the
  • Step b) adding the product of Step a) above to a mixture of benzylmagnesium chloride, benzylmagnesium bromide, or benzylmagnesium iodide in a solvent selected from tetrahydrofuran, 1 ,4-dioxane, hexanes, r ⁇ -heptane, toluene, diethyl ether, and tert-butyl methyl ether to produce the addition
  • a solvent selected from tetrahydrofuran, 1 ,4-dioxane, hexanes, r ⁇ -heptane, toluene, diethyl ether, and tert-butyl methyl ether
  • Step b) adding the products of Step b) above to a mixture of a base selected from potassium hydroxide, sodium hydroxide, lithium hydroxide, and cesium hydroxide in a solvent selected from ethylene glycol, 2-methoxyethyl ether, 1 ,4-dioxane, and diethylene glycol, and stirring the mixture, and then acidifying to produce the carboxylic acids of formulas (24a)
  • a base selected from potassium hydroxide, sodium hydroxide, lithium hydroxide, and cesium hydroxide
  • a solvent selected from ethylene glycol, 2-methoxyethyl ether, 1 ,4-dioxane, and diethylene glycol
  • Step b) adding the products of Step b) above to an acid mixture selected from 6-12 M HCl, 12 M H2SO4, 10%-48% wt/wt hydrobromic acid, and HBr in aqueous acetic acid, and stirring to produce the carboxylic acids of
  • Step c) contacting the products of Step c) above with an amine selected from (S)- ⁇ -methyl-benzylamine, (R)- ⁇ -methyl-benzylamine, (R)-(+)-l- (naphthyl)ethylamine, (S)-(+)-l-(naphthyl)ethylamine, triethylamine, diisopropylethylamine, dicyclohexylamine, benzylamine, dibenzylamine, morpholine, N-methylmorpholine, piperidine, N-methylpiperidine, and pyridine in a solvent selected from N,N-dimethylformamide, chloroform, hexanes, acetone, ethanol, methanol, zso-propanol, diethyl ether, dichloromethane, benzene, toluene, n-pentane, n-hexane, n-h
  • Step d) adding the product of Step d) to a mixture selected from aqueous hydrochloric acid, aqueous sulfuric acid, aqueous acetic acid, hydrochloric acid dissolved in acetic acid, and hydrochloric acid dissolved in acetic acid and water, and stirring to produce the carboxylic acid of formula (26)
  • Step d) partitioning the product of Step d) between a mixture of aqueous hydrochloric acid and a solvent selected from chloroform, dichloromethane, ethyl acetate, ethyl ether, tetrahydrofuran, 1 ,4-dioxane, toluene, and tert-butylmethylether, and drying and evaporating the organic
  • a process for the preparation of a compound of formula (26) wherein R is Ci -CJ O alkyl or C3-C1 Q cycloalkyl, and pharmaceutically acceptable salts thereof which comprises: a) adding a cyanoacetate of formula (A) NC V ⁇ / -' L '' J 2 1 , wherein Ri is
  • Step b) adding the products of Step b) above to a mixture of potassium hydroxide in ethylene glycol, and heating the mixture at 100°C to 200°C, and then acidifying to produce the hydrolysis products of formulas (24a)
  • Step d) adding the product of Step d) to aqueous hydrochloric acid and stirring to
  • R wherein R is Ci -Ci Q alkyl or C3-C1 Q cycloalkyl, and pharmaceutically acceptable salts thereof.
  • Preferred is a compound of formula (6) and pharmaceutically acceptable salts thereof wherein R is CI -CJ Q alkyl.
  • More preferred is a compound of formula (6) and pharmaceutically acceptable salts thereof wherein R is selected from methyl, ethyl, and n-propyl.
  • R is Cj-Ci Q alkyl or C3-C1 Q cycloalkyl and pharmaceutically acceptable salts thereof.
  • Preferred is a compound of formula (26) and pharmaceutically acceptable salts thereof wherein R is C ⁇ -C ⁇ Q alkyl .
  • More preferred is a compound of formula (26) and pharmaceutically acceptable salts thereof wherein R is selected from methyl, ethyl, and n-propyl.
  • a compound of formula (26) named ((1R,3S)-1- benzyl-3-methyl-cyclopentyl)-acetic acid.
  • the invention provides a compound of Formula I, wherein R is as defined above, prepared according to any one ofthe processes for the preparation of a compound of Formula I described above.
  • R is CJ -CI Q alkyl, prepared according to any one ofthe processes for the preparation of a compound of Formula I described above.
  • R is selected from methyl, ethyl, and w-propyl, prepared according to any one ofthe processes for the preparation of a compound of Formula I described above.
  • a compound of Formula I selected from: ((lR,3S)-l-aminomethyl-3-methyl-cyclopentyl)-acetic acid; and ((lR,3S)-l-aminomethyl-3-methyl-cyclopentyl)-acetic acid hydrochloride, prepared according to any one ofthe processes for the preparation of a compound of Formula I described above.
  • the invention provides a compound of Formula II, wherein R is as defined above, prepared according to any one ofthe processes for the preparation of a compound of Formula II described above.
  • R is as defined above, prepared according to any one ofthe processes for the preparation of a compound of Formula II described above.
  • Preferred is a compound of Formula II, wherein R is C ⁇ -C ⁇ o alkyl, prepared according to any one ofthe processes for the preparation of a compound of Formula II described above.
  • R is selected from methyl, ethyl, and «-propyl, prepared according to any one ofthe processes for the preparation of a compound of Formula II described above.
  • a compound of Formula II selected from: ((lS,3R)-l-aminomethyl-3-methyl-cyclopentyl)-acetic acid; and ((1 S,3R)-l-aminomethyl-3-methyl-cyclopentyl)-acetic acid hydrochloride, prepared according to any one ofthe processes for the preparation of a compound of Formula II described above.
  • the invention provides a compound of Formula III, wherein R is as defined above, prepared according to any one ofthe processes for the preparation of a compound of Formula III described above.
  • the invention provides a compound of Formula IV, wherein R is as defined above, prepared according to any one ofthe processes for the preparation of a compound of Formula IV described above. Further, the invention provides a compound of formula (6), wherein R is as defined above, prepared according to any one ofthe processes for the preparation of a compound of formula (6) described above.
  • the invention provides a compound of formula (26), wherein R is as defined above, prepared according to any one ofthe processes for the preparation of a compound of formula (26) described above.
  • the invention provides a compound of Formula II selected from: ((lS,3R)-l-aminomethyl-3-methyl-cyclopentyl)-acetic acid; ((1 S,3R)-1 -aminomethyl-3-methyl-cyclopentyl)-acetic acid hydrochloride; ((lS,3R)-l-aminomethyl-3-ethyl-cyclopentyl)-acetic acid;
  • R ⁇ is H, alkyl, or benzyl.
  • Rj is H, alkyl, or benzyl.
  • R is Ci -C J Q alkyl or C3-C1 Q cycloalkyl.
  • R is Ci -Ci Q alkyl or C3-C10 cycloalkyl.
  • R is CJ -CI Q alkyl or C3-C10 cycloalkyl
  • R is C J -CJ O alkyl or C3-C10 cycloalkyl
  • R is Ci -Ci Q alkyl or C3-C10 cycloalkyl
  • R is Ci -Cj Q alkyl or C3-C1 Q cycloalkyl
  • the instant invention is an important process as it permits the synthesis of single isomers; it is a route to stereospecific 3-substituted 5-membered rings of formula
  • a key feature ofthe invention is the stereoselective preparation of a compound of formula (6) by selective fractional crystallization of a salt of formula (5) from a mixture of compounds of formulas (4a) and (4b), and conversion of a salt of formula (5) to a compound of formula (6).
  • Another feature ofthe invention is the conversion of a compound of formula (2) to a mixture of compounds of formulas (3a) and (3b) wherein the yield of a compound of formula (3 a) over a diastereomer of formula (3 b) may be enhanced by optimizing certain reaction parameters such as, for example, temperature.
  • Reaction of a compound of formula (2) at a relatively low temperature generally provides for a relatively higher yield of a compound of formula (3a) over (3b) than when the reaction is run at a higher temperature.
  • the invention also provides for translation ofthe stereochemistry at the two chiral carbons ofthe cyclopentane ring ofthe resulting pure enantiomer of formula (6) into enantiomerically pure compounds of
  • Another key feature ofthe invention is the stereoselective preparation of a compound of formula (26) by selective fractional crystallization of salt of formula (25) from a mixture of compounds of formulas (24a) and (24b), and conversion of a salt of formula (25) to a compound of formula (26).
  • Another feature ofthe invention is the conversion of a compound of formula (22) to a mixture of compounds of formulas (23a) and (23b) wherein the yield of a compound of formula (23a) over a diastereomer of formula (23b) may be enhanced by optimizing certain reaction parameters such as, for example, temperature.
  • Reaction of a compound of formula (22) at a relatively low temperature generally provides for a relatively higher yield of a compound of formula (23a) over (23b) than when the reaction is run at a higher temperature.
  • the invention also provides for translation ofthe stereochemistry at the two chiral carbons ofthe cyclopentane ring ofthe resulting pure enantiomer of formula (26) into enantiomerically pure compounds of Formulas III or IV with little or no racemization.
  • the final products are useful as agents in the treatment of epilepsy, faintness attacks, hypokinesia, cranial disorders, neurodegenerative disorders, depression, anxiety, panic, pain, neuropathological disorders, gastrointestinal disorders such as irritable bowel syndrome (IBS), inflammation especially arthritis, sleep disorders, premenstrual syndrome, and hot flashes.
  • IBS irritable bowel syndrome
  • R is Ci -Ci Q alkyl or C3-C1 Q cycloalkyl.
  • Examples 1 and 3 below each show a synthesis of a compound of Formula II wherein R is methyl.
  • Example 2 shows a synthesis of a compound of Formula I wherein R is methyl. It is understood that compounds of Formulas I, II, III, or IV, or a pharmaceutically acceptable salt thereof, produced by a hydrolysis reaction such as, for example, step j) in the above process for the preparation of a compound of Formula I, or a pharmaceutically acceptable salt thereof, or the process described above wherein a compound of formula (41) is hydrolyzed, may be formed as an acid or base salt thereof, which salt may be optionally converted to a free amino acid form or a pharmaceutically acceptable salt form thereof by methods well known to a skilled person in the pharmaceutical or chemical arts.
  • Cj-Ci Q alkyl means a straight or branched alkyl group or radical containing from 1 to 10 carbon atoms.
  • CI-CJ O alkyl include methyl, ethyl, 1-propyl, 2-propyl, 1 -butyl, 2-butyl, 2- methyl-1-propyl, 1,1-dimethylethyl, 1-pentyl, 2-pentyl, 3-pentyl, 2,2- dimefhylpropyl, 1-hexyl, 2-hexyl, 3-hexyl, 4-methyl- 1-pentyl, 1-heptyl, 2-heptyl, 3-heptyl, 4-heptyl, 5 -methyl- 1-hexyl, 1-octyl, 2-octyl, 3-octyl, 4-octyl, 6-methyl- 1-heptyl, 5,5-dimethylhexyl, 1-nonyl, 2-nonyl, 1-decyl, and 2-decyl.
  • C3-C10 cycloalkyl means a cycloalkyl group or radical having from 3 to 10 carbon atoms.
  • Illustrative examples of a C3-C1 Q cycloalkyl include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl and cyclodecyl.
  • stereoisomer means any of a group of isomers in which identical atoms are linked in the same order but differ in their spatial arrangement.
  • NCCH 2 CO2Et (i) NCCH 2 CO2Et, catalyst (e.g., NH 4 OAc, ACOH);
  • (x) conversion to the free amino acid using, for example, H2O and alkali hydroxide (e.g., NaOH).
  • alkali hydroxide e.g., NaOH
  • NCCH 2 CO2Et (i) NCCH 2 CO2Et, catalyst (e.g., NH 4 OAc, ACOH);
  • hydrolysis using, for example, alkali hydroxide (e.g., KOH);
  • a) resolution using a resolving agent e.g., (R)- or (S)- ⁇ - methylbenzylamine);
  • conversion of salt of enriched stereoisomer to the free acid using, for example, hydrochloric acid;
  • chlorination using, for example, (COCl)2 or SOCI2;
  • tBuOH and base e.g., Et3N);
  • oxidation using, for example, RUCI3 and NaIO4;
  • esterification using, for example, (CH3)3SiCHN2 and MeOH;
  • dealkylation using, for example, CF3CO2H;
  • (x) (PhO)2P(O)N3 and a base e.g., Et3N);
  • the aqueous layer was acidified to pH 1 with 4N hydrochloric acid and re-extracted with ethyl acetate (200 mL), dried (MgSO4), and the solvent was evaporated under reduced pressure. The residue was purified by chromatography
  • IR thin film (cm" 1 ) 1710 (C O); iH-NMR (400 MHz; DMSO-tt ⁇ ): ⁇ 2.96 (IH, d, J 12.8, CH4H B NH ), 2.90 (IH, d, J 12.8, CH A H#NH2), 2.40 (2H, s, CH 2 COOH), 2.04 (IH, m, CHMe), 1.81-1.61, 1.51-1.43, 1.21-1.11 (5H, m), 1.06 (IH, dd, J 12.8, 10.4), 0.97 (3H, d, J6.35, Me);
  • Trimethylsilyldiazomethane (31.5 mL of a 2 M solution in hexanes, 63 mmol) was added dropwise to a stirring solution of ((lS,3R)-l-benzyl-3-methyl-cyclopentyl)- acetic acid (10 g, 43 mmol) in toluene (80 mL) and methanol (20 mL) at 0°C under argon, and the mixture was allowed to warm to room temperature. The mixture was stirred for 1 hour, and then the solvent was evaporated under reduced pressure.
  • Diphenylphosphoryl azide (8.07 mL, 37.4 mmol), triethylamine (5.36 mL, 39 mmol), and ((lS,3R)-l-methoxycarbonylmethyl-3-methyl-cyclopentyl)-acetic acid (7.93 g, 37 mmol) were refluxed in toluene (80 mL) for 17 hours. The mixture was allowed to cool and then taken up in ethyl acetate (250 mL), washed with saturated aqueous sodium hydrogen carbonate (250 mL), brine (100 mL), and dried (MgSO4). The solvent was removed under reduced pressure to give
  • Oxalyl chloride (4.14 mL, 47 mmol) was added dropwise to a stirring solution of ((lS,3R)-l-benzyl-3-methyl-cyclopentyl)-acetic acid (10 g, 43 mmol) in dichloromethane under argon at room temperature.
  • the reaction mixture was cooled to 5°C, dimethylformamide (1 mL) was carefully added, and the mixture was allowed to warm to room temperature and stirred for a further 2 hours.
  • the solvent was removed in vacuo and the residue diluted with dichloromethane (60 mL).
  • 1,1-Dimethylethanol (15 mL) was carefully added to the reaction mixture under argon followed by diisopropylethylamine (11.5 mL, 65 mmol). The mixture was stirred for 17 hours and then taken up in ethyl acetate, washed with saturated aqueous sodium hydrogen carbonate (2 x 200 mL), and dried (MgSO4).
  • Trimethylsilyldiazomethane 14 mL of a 2 M solution in hexanes, 26.9 mmol was added dropwise to a stirring solution of [(lS,3R)-l-carboxymethyl-3-methyl- cyclopentyl] -acetic acid tert-butyl ester (6.9 g, 26.9 mmol) in toluene (60 mL) and methanol (15 mL) at 10°C under argon, and the mixture was allowed to warm to room temperature. The mixture was stirred for 2 hours, and then the solvent was evaporated under reduced pressure. The residue was taken up in ethyl acetate

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Abstract

The instant invention is a route to stereospecific 3-substituted 5-membered ring isomers of Formula (A). The final products are useful as agents in the treatment of epilepsy, faintness attacks, hypokinesia, cranial disorders, neurodegenerative disorders, depression, anxiety, panic, pain, neuropathological disorders, gastrointestinal disorders such as irritable bowel syndrome (IBS), inflammation especially arthritis, sleep disorders, premenstrual syndrome, and hot flashes. The invention provides novel routes to synthesize stereoselectively analogs of gabapentin (Neurontin®) of Formulas (I), (II), (III) and (IV) wherein R is C1-C10 alkyl or C3-C10 cycloalkyl and pharmaceutically acceptable salts thereof.

Description

METHOD FOR THE STEREOSELECTIVE SYNTHESIS OF CYCLIC AMINO ACIDS
BACKGROUND OF THE INVENTION
Compounds of formula
H^-CT^-C-C^-COOR,
(CH2)n
wherein R] is hydrogen or a lower alkyl radical and n is 4, 5, or 6 are known in
United States Patent Number 4,024,175 and its divisional United States Patent Number 4,087,544. The uses disclosed are: protective effect against cramp induced by thiosemicarbazide; protective action against cardiazole cramp; the cerebral diseases, epilepsy, faintness attacks, hypokinesia, and cranial traumas; and improvement in cerebral functions. The compounds are useful in geriatric patients. The patents are hereby incoφorated by reference.
United States Serial Number 09/485,382 filed February 8, 2000 teaches in part compounds of Formula I
Figure imgf000002_0001
or a pharmaceutically acceptable salt thereof wherein R is hydrogen or a lower alkyl; and R\ to Rg are each independently selected from hydrogen, straight or branched alkyl of from 1 to 6 carbon atoms, phenyl, benzyl, fluorine, chlorine, bromine, hydroxy, hydroxymethyl, amino, aminomethyl, trifluoromethyl, -CO2H,
-CO Ri5, -CH2CO2H, -CH2CO2R15, -OR15 wherein Ri 5 is a straight or branched alkyl of from 1 to 6 carbons, phenyl, or benzyl, and R\ to Rg are not simultaneously hydrogen. This patent application is hereby incorporated by reference.
United States Patent Number 5,929,116 describes endothelin antagonists of formulas
Figure imgf000003_0001
wherein Rl is -X(CH2)nAr;
R2 is Ar;
P1 is -X(CH2)nR8; P is -X(CH2)nRg, or -XR9Y;
R3 and R5 are independently hydrogen, Ri 1 , OH, Cj.g alkoxy, S(O)ςRι \, N(Rg)2, Br, F, I, Cl, CF3, NHCOR6, -Ri 1 CO2R7, -XR9-Y, or -X(CH2)nRg wherein each methylene group within -X(CH2)nRg may be unsubstituted or substituted by one or two -(CH2)nAr groups; R4 is hydrogen, Rn, OH, Cι_5 alkoxy, S(O)qRι 1, N(R6)2, -X(Rι 1), Br, F, I, Cl, or NHCORg wherein the C1.5 alkoxy may be unsubstituted or substituted by OH, methoxy, or halogen; Rg is independently hydrogen or C1.4 alkyl;
R7 is independently hydrogen, C . alkyl, or (CH2)nAr; Rg is hydrogen, Ru, CO2R7, PO3H2, SO2NR7R! ] , NR7SO2Rι 1 , P(O)(OH)R7,
CN, -C(O)N(R6) , tetrazole, or ORg; R9 is C1.10 alkyl, C2-10 alkenyl, or phenyl, all of which may be unsubstituted or substituted by one or more OH, N(Rg)2, COOH, >C=O, halogen, or
XC 1.5 alkyl; RI Q is Rβ or R4; R\ \ is C1 _g alkyl, C2-g alkenyl, C2- alkynyl, all of which may be unsubstituted or substituted by one or more OH, CH2OH, N(Rg)2, or halogen; X is (CH2)n, O, NR6, or S(O)q; Y is CH3 or X(CH2)nAr; Ar is:
Figure imgf000004_0001
(a) (b) naphthyl, indolyl, pyridyl, thienyl, oxazolidinyl, oxazolyl, thiazolyl, isothiazolyl, pyrazolyl, triazolyl, tetrazolyl, imidazolyl, imidazolidinyl, thiazolidinyl, isoxazolyl, oxadiazolyl, thiadiazolyl, morpholinyl, piperidinyl, piperazinyl, pyrrolyl, or pyrimidyl; all of which may be unsubstituted or substituted by one or more R3 or R4 groups;
A is >C=O, or [C(R6)2]m;
B is -CH2- or -O-; Z\, ∑2, Z3, and Z4 are independently hydrogen, C1 _g alkyl, C2_ alkenyl,
C2.g alkynyl, OH, Cμg alkoxy, S(O)qCι _8 alkyl, N(R6)2, Br, F, I, Cl, NHCORg, -X(CH2)nRg, XR9Y, phenyl, benzyl, or C3.6 cycloalkyl wherein the C1.g alkyl, C2- alkenyl, or C2_g alkynyl may be optionally substituted by COOH, OH, CO(CH2)nCH3, CO(CH2)nCH2N(R6)2, or halogen; q is zero, one, or two; n is an integer from 0 to 6; m is 1, 2, or 3; and the dotted line in Formula (I) indicates the optional presence of a double bond; or a pharmaceutically acceptable salt thereof; provided that
• when the optional double bond is present, there is only one R] Q, there is no
Pi, and P2 is not NRgRoY; • X is not NRg, and Z3 is not OH or N(Rg)2 in Formula (III);
• Zi and Z3 are not OH, N(Rg)2, or Iodine in Formula (II);
• when the optional double bond is present in Formula (I) and X-R2 is attached to the double bond, X is not NRg; • when the optional double bond is present in Formula (I) and Ri is attached directly to the double bond, R\ is not NRgAr;
• when R3, R5, Z1 , Z2, or Z3 is X(CH2)nRg and n is not zero, X is oxygen or NRg when Rg is ORg or CO H.
Also included in the invention are pharmaceutically acceptable salts ofthe active compounds.
Most or all ofthe desired pharmacological activity of a compound comprised of two or more stereoisomers frequently resides in just one ofthe stereoisomers. The other stereoisomer(s) typically is inactive at best or exhibits undesirable side effects such as, for example, toxicity. Therefore where a compound is comprised of two or more stereoisomers, it is important, and sometimes mandatory, to develop a method of selectively preparing the beneficial stereoisomer in a form that is free from, or almost free from, contamination by the other inactive or harmful stereoisomer(s). However, usually it is very difficult to discover a method for the preparation of a beneficial stereoisomer in a form that is free from, or almost free from, contamination by the other inactive or harmful stereoisomer(s). Unexpectedly, we have invented novel preparations of certain important 3-substituted cyclopentyl-containing, amino acid analogs of gabapentin, a marketed anticonvulsant, which provide the desirable stereoisomers with a high degree of stereochemical purity. None of the above teach the synthesis ofthe instant invention.
SUMMARY OF THE INVENTION
The instant invention encompasses novel synthetic routes for the preparation of important 3-substituted cyclopentyl-based analogs of gabapentin and pharmaceutically acceptable salts thereof. Gabapentin, marketed under the trade name Neurontin® for the treatment of seizure disorders, particularly epilepsy, provides well-known medical benefits to patients in need of such treatment. The instant invention encompasses novel synthetic routes for the preparation of 3-substituted cyclopentyl-based analogs of gabapentin and pharmaceutically acceptable salts thereof that enable the synthesis of each stereoisomer of these analogs with a high degree of stereochemical purity. These routes provide access to pure stereoisomers of Formulas I, II, III, and IV
Figure imgf000006_0001
wherein R is CI -CI Q alkyl or C3-C10 cycloalkyl. Further, the invention encompasses the key intermediates of formulas (6) and (26). Still further, the invention provides novel synthetic routes for the preparation of compounds of formulas (6) and (26). The routes enable the synthesis of each stereoisomer of compounds of formulas (6) and (26) with a high degree of stereochemical purity. These routes provide access to pure stereoisomers of formulas (6) and (26) wherein R is C]-Cιo alkyl or C3-C10 cycloalkyl.
Figure imgf000006_0002
(6) (26)
The invention provides a process for the preparation of a compound of Formula I
Figure imgf000007_0001
wherein R is C[-Cι Q alkyl or C3-C1 o cycloalkyl, and pharmaceutically acceptable salts thereof, which comprises: a) adding a cyanoacetate of formula (A)
Figure imgf000007_0002
is alkyl or benzyl, to a mixture of a chiral cyclopentanone of formula (1)
a solvent, a carboxylic acid, and a Knoevenagel reaction
Figure imgf000007_0003
R catalyst, and stirring the mixture in the presence of a means of removing
water to produce the alkene of formula (2)
Figure imgf000007_0004
R b) adding the product of Step a) above to a mixture of benzylmagnesium chloride, benzylmagnesium bromide, or benzylmagnesium iodide, in a solvent to produce the addition products of formulas (3 a)
Figure imgf000007_0005
c) adding the products of Step b) above to a mixture of a base selected from potassium hydroxide, sodium hydroxide, lithium hydroxide, or cesium hydroxide in a solvent and stirring, and then acidifying to produce the carboxylic acids of formulas (4a) and (4b)
Figure imgf000008_0001
R
Figure imgf000008_0002
R adding the products of Step b) above to an acid mixture and stirring to
produce the carboxylic acids of formulas (4a) and (4b)
Figure imgf000008_0003
R
Figure imgf000008_0004
d) contacting the products of Step c) above with an amine in a solvent, and recrystallizing the salt so formed to produce the enriched diastereomer of
formula (5) the amine salt;
Figure imgf000008_0005
e) converting the product of Step d) to a carboxylic acid of formula (6)
Figure imgf000008_0006
f) adding the product of Step e) to a mixture of iodomethane, a solvent, and a
base, and stirring to produce the ester of formula (7)
Figure imgf000009_0001
or adding the product of Step e) to methanol and an acid to produce the
ester of formula (7)
Figure imgf000009_0002
R or adding the product of Step e) above to trimethylsilyldiazo-methane and methanol in a solvent to produce the ester of formula (7)
Figure imgf000009_0003
R or adding the product of Step e) to a solution of diazomethane or trimethylsilyl-diazomethane in a solvent to produce ester of formula (7)
Figure imgf000009_0004
g) adding the product of Step f) to a mixture of carbon tetrachloride or ethyl acetate, and acetonitrile, water, sodium periodate, and ruthenium(III) chloride, and stirring to produce the carboxylic acid of formula (8)
Figure imgf000010_0001
R h) adding the product of Step g) to a mixture of a tertiary amine base, a solvent, and diphenylphosphoryl azide (DPP A), and stirring to produce the
isocyanate of formula (9) ; or adding the product of
Figure imgf000010_0002
R
Step g) above to ethyl chloroformate or isobutyl chloroformate and a base in a solvent at a temperature of from -40°C to 78°C, followed by adding a solution of sodium azide in water and tetrahydrofuran or acetone, followed by adding toluene or benzene, and refluxing to produce the isocyanate of
formula (9)
Figure imgf000010_0003
i) adding the product of Step h) to a mixture of a solvent and methanol, and stirring to produce the carbamate of formula (10)
Figure imgf000010_0004
R j) adding the product of Step i) to a mixture of a solvent and aqueous hydrochloric acid, and stirring to produce a compound of formula (la)
Figure imgf000011_0001
R k) converting the product of Step j) to a compound of formula (I)
? an£j further converting, if desired, to a
Figure imgf000011_0002
pharmaceutically acceptable salt by known means.
This process is outlined in Scheme 1.
Scheme 1
Figure imgf000012_0001
(1 ) (2) (3a) (3b)
Figure imgf000012_0002
Figure imgf000012_0003
(I) (la) (10)
Preferred is a process for the preparation of a compound of Formula I wherein R is Ci -Ci Q alkyl or C3-C10 cycloalkyl, and pharmaceutically acceptable salts thereof, which comprises: a) adding a cyanoacetate of formula (A)
Figure imgf000012_0004
wherein R\ is selected from methyl, ethyl, «-propyl, w -propyl, rø-butyl, »o-butyl, sec-butyl, tert-butyl, and benzyl to a mixture of a chiral cyclopentanone of formula (1) a solvent selected from tetrahydrofuran, 1 ,4-
Figure imgf000013_0001
R dioxane, tert-butylmethylether, chloroform, dichloromethane, acetonitrile, ethyl ether, ethyl acetate, hexanes, N,N-dimethylformamide, dimethylsulfoxide, ethanol, tert-butanol, toluene, benzene, xylenes, and «-heptane, acetic acid, and a Knoevenagel reaction catalyst selected from β-alanine, ammonium acetate, and piperidine, and stirring the mixture in the presence of a means of removing water selected from azeotropic distillation, activated molecular sieves, anhydrous magnesium sulfate, anhydrous sodium sulfate, anhydrous sodium carbonate, anhydrous potassium carbonate, anhydrous cesium carbonate, trimethyl orthoformate, and triethyl orthoformate to produce the alkene of formula (2)
Figure imgf000013_0002
R adding the product of Step a) above to a mixture of benzylmagnesium chloride, benzylmagnesium bromide, or benzylmagnesium iodide in a solvent selected from tetrahydrofuran, benzene, 1 ,4-dioxane, hexanes, ^-heptane, toluene, diethyl ether, and tert-butyl methyl ether to produce
the addition products of formulas (3 a) and
Figure imgf000013_0003
R
Figure imgf000013_0004
R c) adding the products of Step b) above to a mixture of a base selected from potassium hydroxide, sodium hydroxide, lithium hydroxide, and cesium hydroxide in a solvent selected from ethylene glycol, 2-methoxyethyl ether, 1 ,4-dioxane, and diethylene glycol, and stirring the mixture, and then acidifying to produce the carboxylic acids of formulas (4a)
Figure imgf000014_0001
adding the products of Step b) above to an acid mixture selected from 6-12 M HCl, 12 M H2SO4, 10%-48% wt/wt hydrobromic acid, and HBr in aqueous acetic acid, and stirring to produce the carboxylic acids of
formulas (4a)
Figure imgf000014_0002
d) contacting the products of Step c) above with an amine selected from
(S)-α-methyl-benzylamine, (R)-α-methyl-benzylamine, (R)-(+)-l- (naphthyl)ethylamine, (S)-(+)- 1 -(naphthyl)ethylamine, triethylamine, diisopropylethylamine, dicyclohexylamine, benzylamine, dibenzyl amine, morpholine, N-methylmorpholine, piperidine, N-methylpiperidine, and pyridine in a solvent selected from N,N-dimethylformamide, chloroform, benzene, xylenes, hexanes, acetone, ethanol, methanol, /so-propanol, diethyl ether, dichloromethane, benzene, toluene, n-pentane, n-hexane, n-heptane, ethyl acetate, acetonitrile, tert-butyl methyl ether, tetrahydrofuran, and 1 ,4-dioxane, and recrystallizing the salt so formed to produce the enriched diastereomer of formula (5)
Figure imgf000015_0001
as the amine salt; e) adding the product of Step d) to a mixture selected from aqueous hydrochloric acid, aqueous sulfuric acid, aqueous acetic acid, hydrochloric acid dissolved in acetic acid, or hydrochloric acid dissolved in acetic acid to which water is added and stirring to produce the carboxylic acid of
formula (6) or
Figure imgf000015_0002
partitioning the product of Step d) between a mixture of aqueous hydrochloric acid and a solvent selected from chloroform, dichloromethane, ethyl acetate, ethyl ether, tetrahydrofuran, 1 ,4-dioxane, toluene, and tert-butylmethylether, and drying and evaporating the organic
layer to produce the carboxylic acid of formula (6)
Figure imgf000015_0003
f) adding the product of Step e) above to a mixture of iodomethane, a solvent selected from dichloromethane, chloroform, tetrahydrofuran, toluene, and 1,4-dioxane, and a base selected from l,8-diazabicyclo[5.4.0]undec-7-ene (DBU), diisopropylethylamine, triethylamine, and 1,5- diazabicyclo[4.3.0]non-5-ene (DBN), and stirring at a temperature of from
-40°C to 1 10°C to produce the ester of formula (7)
Figure imgf000015_0004
or adding the product of Step e) above to a mixture of methanol and concentrated sulphuric acid, concentrated hydrochloric acid, or hydrogen chloride at a temperature of from 0°C to 100°C to produce the ester of
formula (7) ; or adding the product of Step e) above to
Figure imgf000016_0001
R trimethylsilyldiazomethane and methanol in benzene or toluene at a temperature of from -40°C to 100°C to produce the ester of formula (7)
; or adding the product of Step e) above to
Figure imgf000016_0002
R diazomethane or trimethylsilyldiazomethane in a solvent selected from benzene, toluene, dichloromethane, and diethyl ether at a temperature of from -40°C to 40°C to give a compound of formula (7)
Figure imgf000016_0003
g) adding the product of Step f) to a mixture of carbon tetrachloride or ethyl acetate, and acetonitrile, water, sodium periodate, and ruthenium(III) chloride, and stirring at a temperature from -40°C to 80°C to produce the
carboxylic acid of formula (8)
Figure imgf000016_0004
R h) adding the product of Step g) above. to a mixture of a base selected from triethylamine and diisopropylethylamine, a solvent selected from toluene, benzene, xylenes, tetrahydrofuran, diethyl ether and «-heptane, and diphenylphosphoryl azide (DPP A), and stirring at a temperature of from 0°C to 150°C to produce the isocyanate of formula (9)
or adding the product of Step g) above to ethyl
Figure imgf000017_0001
R chloroformate or isobutyl chloroformate, a base selected from triethylamine and diisopropylethylamine, and a solvent selected from tetrahydrofuran, acetone, and diethyl ether at a temperature of from -40°C to 78°C, followed by adding a solution of sodium azide in water and tetrahydrofuran or acetone, followed by adding toluene or benzene, and
refluxing to produce the isocyanate of formula (9)
Figure imgf000017_0002
R i) adding the product of Step h) to a mixture of a solvent selected from toluene, benzene, xylenes and w-heptane, and methanol, and stirring at a temperature from 0°C to 150°C to produce the carbamate of formula (10)
Figure imgf000017_0003
R j) adding the product of Step i) to a mixture of a solvent selected from water, acetic acid, and 1 ,4-dioxane, and aqueous hydrochloric acid at a concentration of from 0.01 M to 12 M, and stirring at a temperature from 0°C to 115°C to produce a compound of formula la
Figure imgf000018_0001
R and k) converting the product of Step j) to a compound of Formula I
N"2 , and further converting, if desired, to a pharmaceutically
Figure imgf000018_0002
R acceptable salt by known means. More preferred is a process for the preparation of a compound of Formula I wherein R is Ci -C J Q alkyl or C3-C10 cycloalkyl, and pharmaceutically acceptable salts thereof, which comprises: a) adding a cyanoacetate of formula (A)
Figure imgf000018_0003
, wherein R\ is
ethyl, to a mixture of a chiral cyclopentanone of formula (1)
Figure imgf000018_0004
R toluene, acetic acid, and a Knoevenagel reaction catalyst which is ammonium acetate, and heating the mixture at reflux over a Dean- Stark
trap to produce the alkene of formula (2)
Figure imgf000018_0005
R b) adding the product of Step a) above to a mixture of benzylmagnesium chloride in dry tetrahydrofuran at -100°C to 25°C to produce the addition products of formulas (3a) and (3b)
Figure imgf000019_0001
R
Figure imgf000019_0002
R c) adding the products of Step b) above to a mixture of potassium hydroxide in ethylene glycol, and heating the mixture at 100°C to 200°C, and then acidifying to produce the hydrolysis products of
formulas (4a)
Figure imgf000019_0003
d) contacting the products of Step c) above with (S)-α-methyl-benzylamine in ethyl acetate, and recrystallizing the salt so formed from ethyl acetate to
produce the enriched diastereomer of formula (5)
Figure imgf000019_0004
as the (S)-α-methyl-benzylamine salt; e) adding the product of Step d) to aqueous hydrochloric acid and stirring to
produce the carboxylic acid of formula (6)
Figure imgf000019_0005
f) adding the product of Step e) to a mixture of iodomethane, dichloromethane, and l,8-diazabicyclo[5.4.0]undec-7-ene (DBU), and stirring to produce the ester of formula (7) ; or addin
Figure imgf000020_0001
R the product of Step e) to methanol and concentrated sulfuric acid to
produce the ester of formula (1) , ' or adding the
Figure imgf000020_0002
product of Step e) to a solution of diazomethane or trimethylsilyldiazomethane in dichloromethane to produce the ester of formula (7)
Figure imgf000020_0003
g) adding the product of Step f) to a mixture of carbon tetrachloride or ethyl acetate, and acetonitrile, water, sodium periodate, and ruthenium(III) chloride, and stirring to produce the carboxylic acid of formula (8)
Figure imgf000020_0004
R h) adding the product of Step g) to a mixture of triethylamine, toluene, and diphenylphosphoryl azide (DPP A), and refluxing to produce the
isocyanate of formula (9) ; 0r adding the product of
Figure imgf000020_0005
R Step g) above to ethyl chloroformate or isobutyl chloroformate and triethylamine in tetrahydrofuran at a temperature of from -40°C to 78°C, followed by adding a solution of sodium azide in water and tetrahydrofuran, followed by adding toluene or benzene, and refluxing to
produce ester of formula (9)
Figure imgf000021_0001
R i) adding the product of Step h) to a mixture of methanol and toluene, and refluxing to produce the carbamate of formula (10)
Figure imgf000021_0002
j) adding the product of Step i) to a mixture of 1 ,4-dioxane and aqueous hydrochloric acid at a concentration of 6 M, and stirring to produce a
compound of formula la
Figure imgf000021_0003
R k) converting the product of Step j) to a compound of Formula I
, and further converting, if desired, to a pharmaceutically
Figure imgf000021_0004
R acceptable salt by known means. Also preferred is a process for the preparation of a compound of Formula I as described above, further characterized in that the intermediate
product (9) formed is reacted, without isolation, with
Figure imgf000022_0001
R methanol to produce the carbamate of formula (10)
Figure imgf000022_0002
Further, the invention provides a process for the preparation of a compound of Formula II
Figure imgf000022_0003
R wherein R is Ci -CI Q alkyl or C3-C10 cycloalkyl, and pharmaceutically acceptable salts thereof, which comprises: a) adding a cyanoacetate of formula (A) NC^/- L> Kj ^ wnerein R\ is alkyl or benzyl, to a mixture of a chiral cyclopentanone of
formula (1) a solvent, a carboxylic acid, and a Knoevenagel
Figure imgf000022_0004
R reaction catalyst, and stirring the mixture in the presence of a means of
removing water to produce the alkene of formula (2)
Figure imgf000023_0001
R b) adding the product of Step a) above to a mixture of benzylmagnesium chloride, benzylmagnesium bromide, or benzylmagnesium iodide, in a solvent to produce the addition products of formulas (3 a)
Figure imgf000023_0002
R R c) adding the products of Step b) above to a mixture of a base selected from potassium hydroxide, sodium hydroxide, lithium hydroxide, and cesium hydroxide and a solvent, and stirring, and then acidifying to produce the
carboxylic acids of formulas (4a) and (4b)
Figure imgf000023_0003
R
Figure imgf000023_0004
R adding the products of Step b) above to an acid mixture and stirring to
produce the carboxylic acids of formulas (4a) and (4b)
Figure imgf000024_0001
R
Figure imgf000024_0002
R d) contacting the products of Step c) above with an amine in a solvent, and recrystallizing the salt so formed to produce the enriched diastereomer of
formula (5) the amine salt; and
Figure imgf000024_0003
e) converting the product of Step d) to a carboxylic acid of formula (6)
Figure imgf000024_0004
f) adding the product of Step e) to a mixture of a tertiary amine base, a solvent, and diphenylphosphoryl azide (DPP A), and stirring to produce the
isocyanate of formula (1 1) ; or adding the product of Step
Figure imgf000024_0005
R e) above to ethyl chloroformate or isobutyl chloroformate and a base in a solvent at a temperature of from -40°C to 78°C, followed by adding a solution of sodium azide in water and tetrahydrofuran or acetone, followed by adding toluene or benzene, and refluxing to produce isocyanate of
formula (11)
Figure imgf000025_0001
g) adding the product of Step f) to a mixture of a solvent and methanol, and
stirring to produce the carbamate of formula (12)
Figure imgf000025_0002
h) adding the product of Step g) to a mixture of carbon tetrachloride or ethyl acetate, and acetonitrile, water, sodium periodate, and ruthenium(III) chloride, and stirring to produce the carboxylic acid of
formula (13)
Figure imgf000025_0003
R i) adding the product of Step h) to a mixture of a solvent and aqueous hydrochloric acid, and stirring to produce a compound of formula (Ila)
Figure imgf000025_0004
R j) converting the product of Step i) to a compound of formula (II)
, and further converting, if desired, to a pharmaceutically
Figure imgf000026_0001
R acceptable salt by known means.
This process is outlined below in Scheme 2.
Scheme 2
Figure imgf000026_0002
(1) (2) (3a) (3b)
amine
[amine-H]
Figure imgf000026_0003
Figure imgf000026_0004
(5a) (4a) (4b)
Figure imgf000026_0005
(6) ( I I) ( 12)
Figure imgf000026_0006
(ii) (Ila) ( 13) Preferred is a process for the preparation of a compound of Formula II wherein R is CI -CJ Q alkyl or C3-C10 cycloalkyl, and pharmaceutically acceptable salts thereof, which comprises: a) adding a cyanoacetate of formula (A) NC^^/- U2K1 wherein Ri is selected from methyl, ethyl, rø-propyl, / ø-propyl, rø-butyl, iso-butyl, sec-butyl, tert-butyl, and benzyl to a mixture of a chiral cyclopentanone of
formula (1) , a solvent selected from tetrahydrofuran, 1 ,4-
Figure imgf000027_0001
R dioxane, tert-butylmethylether, chloroform, dichloromethane, acetonitrile, ethyl ether, ethyl acetate, hexanes, N,N-dimethylformamide, dimethylsulfoxide, ethanol, tert-butanol, toluene, benzene, xylenes, and w-heptane, acetic acid, and a Knoevenagel reaction catalyst selected from β-alanine, ammonium acetate, and piperidine, and stirring the mixture in the presence of a means of removing water selected from azeotropic distillation, activated molecular sieves, anhydrous magnesium sulfate, anhydrous sodium sulfate, anhydrous sodium carbonate, anhydrous potassium carbonate, anhydrous cesium carbonate, trimethyl orthoformate, and triethyl orthoformate to produce the alkene of formula (2)
Figure imgf000027_0002
R b) adding the product of Step a) above to a mixture of benzylmagnesium chloride, benzylmagnesium bromide, or benzylmagnesium iodide in a solvent selected from tetrahydrofuran, benzene, 1 ,4-dioxane, hexanes, ^-heptane, toluene, diethyl ether, and tert-butyl methyl ether to produce the addition products of formulas (3 a) and
Figure imgf000028_0001
Figure imgf000028_0002
R c) adding the products of Step b) above to a mixture of a base selected from potassium hydroxide, sodium hydroxide, lithium hydroxide, and cesium hydroxide in a solvent selected from ethylene glycol, 2-methoxyethyl ether, 1,4-dioxane, and diethylene glycol, and stirring the mixture and then acidifying to produce the carboxylic acids of formulas (4a)
Figure imgf000028_0003
adding the products of Step b) above to an acid mixture selected from 6-12 M HCl, 12 M H2SO4, 10%-48% wt/wt hydrobromic acid, and HBr in aqueous acetic acid, and stirring to produce the carboxylic acids of
formulas (4a)
Figure imgf000028_0004
d) contacting the products of Step c) above with an amine selected from (S)-α-mefhyl-benzylamine, (R)-α-methyl-benzylamine, (R)-(+)-l- (naphthyl)ethylamine, (S)-(+)- 1 -(naphthyl)ethylamine, triethylamine, diisopropylethylamine, dicyclohexylamine, benzylamine, dibenzylamine, morpholine, N-methylmorpholine, piperidine, N-methylpiperidine, and pyridine in a solvent selected from N,N-dimethylformamide, chloroform, benzene,, xylenes, hexanes, acetone, ethanol, methanol, z'sø-propanol, diethyl ether, dichloromethane, benzene, toluene, n-pentane, n-hexane, n-heptane, ethyl acetate, acetonitrile, tert-butyl methyl ether, tetrahydrofuran, and 1 ,4-dioxane, and recrystallizing the salt so formed to
produce the enriched diastereomer of formula (5)
Figure imgf000029_0001
as the amine salt; e) adding the product of Step d) to a mixture selected from aqueous hydrochloric acid, aqueous sulfuric acid, aqueous acetic acid, hydrochloric acid dissolved in acetic acid, and hydrochloric acid dissolved in acetic acid and water, and stirring to produce the carboxylic acid of formula (6)
Figure imgf000029_0002
partitioning the product of Step d) between a mixture of aqueous hydrochloric acid and a solvent selected from chloroform, dichloromethane, ethyl acetate, ethyl ether, tetrahydrofuran, 1 ,4-dioxane, toluene, and tert-butylmethylether, and drying and evaporating the organic
layer to produce the carboxylic acid of formula (6)
Figure imgf000029_0003
f) adding the product of Step e) above to a mixture of a base selected from triethylamine and diisopropylethylamine, a solvent selected from toluene, benzene, xylenes, tetrahydrofuran, diethyl ether and »-heptane, and diphenylphosphoryl azide (DPP A), and stirring at a temperature of from 0°C to 150°C to produce the isocyanate of formula (1 1)
Figure imgf000030_0001
R or adding the product of Step e) above to ethyl chloroformate or isobutyl chloroformate and a base selected from triethylamine and diisopropylethylamine, and a solvent selected from tetrahydrofuran, acetone, and diethyl ether at a temperature of from -40°C to 78°C, followed by adding a solution of sodium azide in water and tetrahydrofuran or acetone, followed by adding toluene or benzene, and
refluxing to produce the isocyanate of formula (11)
Figure imgf000030_0002
g) adding the product of Step f) to a solvent selected from toluene, benzene, xylenes, and ^-heptane, and methanol, and stirring at a temperature from 0°C to 150°C to produce the carbamate of formula (12)
Figure imgf000030_0003
h) adding the product of Step g) to a mixture of carbon tetrachloride or ethyl acetate, and acetonitrile, water, sodium periodate, and ruthenium(III) chloride, and stirring at a temperature from -40°C to 80°C to produce the
carboxylic acid of formula (13)
Figure imgf000030_0004
R i) adding the product of Step h) to a mixture of a solvent selected from water, acetic acid, and 1 ,4-dioxane, and aqueous hydrochloric acid at a concentration of from 0.01 M to 12 M, and stirring at a temperature from 0°C to 115°C to produce a compound of formula Ila
Figure imgf000031_0001
R j) converting the product of Step i) to a compound of Formula II
' anc* fisher converting, if desired, to a pharmaceutically
Figure imgf000031_0002
acceptable salt by known means. More preferred is a process for the preparation of a compound of Formula II wherein R is Cj-Cio alkyl or C3-C1 Q cycloalkyl, and pharmaceutically acceptable salts thereof, which comprises: a) adding a cyanoacetate of formula (A) NC ^/-(-u2Kl , wherein Ri is
ethyl, to a mixture of a chiral cyclopentanone of formula (1)
Figure imgf000031_0003
R toluene, acetic acid, and a Knoevenagel reaction catalyst which is ammonium acetate, and heating the mixture at reflux over a Dean-Stark
trap to produce the alkene of formula (2)
Figure imgf000031_0004
R b) adding the product of Step a) above to a mixture of benzylmagnesium chloride in dry tetrahydrofuran at -100°C to 25°C to produce the addition
products of formulas (3 a)
Figure imgf000032_0001
c) adding the products of Step b) above to a mixture of potassium hydroxide in ethylene glycol, and heating the mixture at 100°C to 200°C, and then acidifying to produce the hydrolysis products of formulas (4a)
Figure imgf000032_0002
d) contacting the products of Step c) above with (S)-α-methyl-benzylamine in ethyl acetate, and recrystallizing the salt so formed from ethyl acetate to
produce the enriched diastereomer of formula (5)
Figure imgf000032_0003
as the (S)-ct-methyl-benzylamine salt; e) adding the product of Step d) to aqueous hydrochloric acid and stirring to
produce the carboxylic acid of formula (6)
Figure imgf000032_0004
f) adding the product of Step e) to a mixture of triethylamine, toluene, and diphenylphosphoryl azide (DPP A), and refluxing to produce the isocyanate of formula (1 1) ; or adding the product of
Figure imgf000033_0001
R
Step e) above to ethyl chloroformate or isobutyl chloroformate and triethylamine in tetrahydrofuran at a temperature of from -40°C to 78°C, followed by adding a solution of sodium azide in water and tetrahydrofuran or acetone, followed by adding toluene or benzene, and
refluxing to produce isocyanate of formula (1 1)
Figure imgf000033_0002
R g) adding the product of Step f) to a mixture of methanol and toluene, and refluxing to produce the carbamate of formula (12)
Figure imgf000033_0003
h) adding the product of Step g) to a mixture of carbon tetrachloride or ethyl acetate, and acetonitrile, water, sodium periodate, and ruthenium(III) chloride, and stirring to produce the carboxylic acid of
formula (13)
Figure imgf000033_0004
R i) adding the product of Step h) to a mixture of 1 ,4-dioxane and aqueous hydrochloric acid at a concentration of 6 M, and stirring to produce a
compound of formula Ila " l
Figure imgf000034_0001
R j) converting the product of Step i) to a compound of Formula II
and further converting, if desired, to a pharmaceutically
Figure imgf000034_0002
R acceptable salt by known means. Also preferred is a process for the preparation of a compound of Formula II as described above, further characterized in that the intermediate
product (11) formed is further reacted, without isolation, with
Figure imgf000034_0003
R
methanol to produce the carbamate of formula ( 12)
Still further, the invention provides a process for the preparation of a compound of Formula II
Figure imgf000035_0001
R wherein R is C\ -C\ Q alkyl or C3-C10 cycloalkyl, and pharmaceutically acceptable salts thereof, which comprises: a) adding a cyanoacetate of formula (A) NC^/- υ2 1 , wherein R\ is alkyl or benzyl, to a mixture of a chiral cyclopentanone of formula (1)
Figure imgf000035_0002
R catalyst, and stirring the mixture in the presence of a means of removing
water to produce the alkene of formula (2)
Figure imgf000035_0003
b) adding the product of Step a) above to a mixture of benzylmagnesium chloride, benzylmagnesium bromide, or benzylmagnesium iodide, in a solvent to produce the addition products of formulas (3 a)
Figure imgf000035_0004
R R c) adding the products of Step b) above to a mixture of a base selected from potassium hydroxide, sodium hydroxide, lithium hydroxide, and cesium hydroxide, in a solvent, and stirring, and then acidifying to produce the carboxylic acids of formulas (4a) (4b)
Figure imgf000036_0001
R
Figure imgf000036_0002
R adding the products of Step b) above to an acid mixture and stirring to
produce the carboxylic acids of formulas (4a) (4b)
Figure imgf000036_0003
Figure imgf000036_0004
R d) contacting the products of Step c) above with an amine in a solvent, and recrystallizing the salt so formed to produce the enriched diastereomer of
formula (5) as the amine salt;
Figure imgf000036_0005
e) converting the product of Step d) to a carboxylic acid of formula (6)
Figure imgf000036_0006
f) adding oxalyl chloride to a mixture ofthe product of Step e), a solvent, and N,N-dimefhylformamide (DMF), and stirring to produce the acid chloride
of formula (14)
Figure imgf000037_0001
g) adding the product of Step f) to a mixture of tert-butyl alcohol, a solvent, and a tertiary amine base, and stirring to produce the ester of formula (15)
Figure imgf000037_0002
h) adding the product of Step g) to a mixture of carbon tetrachloride or ethyl acetate, and acetonitrile, water, sodium periodate, and ruthenium(III) chloride, and stirring to produce the carboxylic acid of formula (16)
Figure imgf000037_0003
R i) adding the product of Step h) to a mixture of a solvent, methanol, and (trimethylsilyl)diazomethane, and stirring to produce the bis ester of
formula (17) . or a(jding me product of Step h) to a
Figure imgf000037_0004
R mixture of iodomethane, a solvent, and a base, and stirring to produce the
bis ester of formula (17)
Figure imgf000038_0001
R j) adding an acid to a mixture ofthe product from Step i) and a solvent, and
stirring to produce the carboxylic acid of formula (18)
Figure imgf000038_0002
k) adding the product of Step j) to a mixture of a tertiary amine base, a solvent, and diphenylphosphoryl azide (DPP A) is added, and stirring to
produce the isocyanate of formula (19) or adding the
Figure imgf000038_0003
R product of Step j) above to ethyl chloroformate or isobutyl chloroformate and a base in a solvent at a temperature of from -40°C to 78°C, followed by adding a solution of sodium azide in water and tetrahydrofuran or acetone, followed by adding toluene or benzene, and refluxing to produce
isocyanate of formula (19)
Figure imgf000038_0004
R 1) adding the product of Step k) to a mixture of a solvent and methanol, and
stirring to produce the carbamate of formula (20)
Figure imgf000039_0001
R m) adding the product of Step 1) to a mixture of a solvent and aqueous hydrochloric acid is added, and stirring to produce a compound of
formula (Ila) -HC1 ; and
Figure imgf000039_0002
R n) converting the product of Step m) to a compound of formula (II)
, and further converting, if desired, to a pharmaceutically
Figure imgf000039_0003
R acceptable salt by known means. This process is outlined in Scheme 3.
Scheme 3
Figure imgf000040_0001
( I ) (2) (3a) (3b)
amine
[amine-H]
Figure imgf000040_0003
Figure imgf000040_0002
(5a) (4a) (4b)
Figure imgf000040_0004
(6) (14) (15) ( 16)
Figure imgf000040_0005
(20) (Ila) (ID
Preferred is a process for the preparation of a compound of Formula II wherein R is Cj-Cio alkyl or C3-C10 cycloalkyl, and pharmaceutically acceptable salts thereof, which comprises: a) adding a cyanoacetate of formula (A) NC^^/- u2 1 wherein Rj is selected from methyl, ethyl, «-propyl, z'so-propyl, rø-butyl, /so-butyl, sec-butyl, tert-butyl, and benzyl to a mixture of a chiral cyclopentanone of
formula (1) , a solvent selected from tetrahydrofuran, 1 ,4-
Figure imgf000041_0001
R dioxane, tert-butylmethylether, chloroform, dichloromethane, acetonitrile, ethyl ether, ethyl acetate, hexanes, N,N-dimethylformamide, dimethylsulfoxide, ethanol, tert-butanol, toluene, benzene, xylenes, and rz-heptane, acetic acid, and a Knoevenagel reaction catalyst selected from β-alanine, ammonium acetate, and piperidine, and stirring the mixture in the presence of a means of removing water selected from azeotropic distillation, activated molecular sieves, anhydrous magnesium sulfate, anhydrous sodium sulfate, anhydrous sodium carbonate, anhydrous potassium carbonate, anhydrous cesium carbonate, trimethyl orthoformate, and triethyl orthoformate to produce the alkene of formula (2)
Figure imgf000041_0002
R b) adding the product of Step a) above to a mixture of benzylmagnesium chloride, benzylmagnesium bromide, or benzylmagnesium iodide in a solvent selected from tetrahydrofuran, benzene, 1 ,4-dioxane, hexanes, 77-heptane, toluene, diethyl ether, and tert-butyl methyl ether to produce the addition products of formulas (3 a) and (3b)
Figure imgf000042_0001
R
Figure imgf000042_0002
R c) adding the products of Step b) above to a mixture of a base selected from potassium hydroxide, sodium hydroxide, lithium hydroxide, and cesium hydroxide in a solvent selected from ethylene glycol, 2-methoxyethyl ether, 1 ,4-dioxane, and diethylene glycol, and stirring the mixture and then acidifying to produce the carboxylic acids of formulas (4a)
Figure imgf000042_0003
adding the products of Step b) above to an acid mixture selected from 6-12 M HCl, 12 M H2SO4, 10%-48% wt/wt hydrobromic acid, and HBr in aqueous acetic acid, and stirring to produce the carboxylic acids of
formulas (4a)
Figure imgf000042_0004
d) contacting the products of Step c) above with an amine selected from (S)-α-methyl-benzylamine, (R)-α-methyl-benzylamine, (R)-(+)-l- (naphthyl)ethylamine, (S)-(+)-l -(naphthyl)ethylamine, triethylamine, diisopropylethylamine, dicyclohexylamine, benzylamine, dibenzylamine, morpholine, N-methylmorpholine, piperidine, N-methylpiperidine, and pyridine in a solvent selected from N,N-dimethylformamide, chloroform, benzene, xylenes, hexanes, acetone, ethanol, methanol, z's -propanol, diethyl ether, dichloromethane, benzene, toluene, n-pentane, n-hexane, n-heptane, ethyl acetate, acetonitrile, tert-butyl methyl ether, tetrahydrofuran, and 1 ,4-dioxane, and recrystallizing the salt so formed to
produce the enriched diastereomer of formula (5)
Figure imgf000043_0001
as the amine salt; e) adding the product of Step d) to a mixture selected from aqueous hydrochloric acid, aqueous sulfuric acid, aqueous acetic acid, hydrochloric acid dissolved in acetic acid, or hydrochloric acid dissolved in acetic acid and water, and stirring to produce the carboxylic acid of formula (6)
Figure imgf000043_0002
partitioning the product of Step d) between a mixture of aqueous hydrochloric acid and a solvent selected from chloroform, dichloromethane, ethyl acetate, ethyl ether, tetrahydrofuran, 1,4-dioxane, toluene, and tert-butylmethylether, and drying and evaporating the organic
layer to produce the carboxylic acid of formula (6) ;
Figure imgf000043_0003
f) adding oxalyl chloride to a mixture ofthe product of Step e), a solvent selected from dichloromethane, chloroform, ethyl ether, toluene, and tert- butyl methyl ether, and 0.01 to 10 mole percent of N,N- dimethylformamide (DMF), and stirring at a temperature from -40°C to
110°C to produce the acid chloride of formula (14)
Figure imgf000044_0001
g) adding the product of Step f) to a mixture of tert-butyl alcohol, a solvent selected from dichloromethane, chloroform, ethyl ether, toluene, and tert- butyl methyl ether, and NN-diisopropylethylamine (DIPEA) or triethylamine, and stirring at a temperature from -40°C to 110°C to
produce the ester of formula (15)
Figure imgf000044_0002
h) adding the product of Step g) to a mixture of carbon tetrachloride or ethyl acetate, and acetonitrile, water, sodium periodate, and rufhenium(III) chloride, and stirring at a temperature from -40°C to 80°C to produce the
carboxylic acid of formula (16) .
Figure imgf000044_0003
R i) adding the product of Step h) to a solvent selected from toluene, benzene, xylenes, and /ϊ-heptane, methanol, and (trimethylsilyl)diazomethane, and stirring at a temperature from 0°C to 150°C to produce the bis ester of
formula (17) . or ad ing the product of Step h) to a
Figure imgf000044_0004
R mixture of iodomethane, a solvent selected from dichloromethane, chloroform, tetrahydrofuran, toluene and 1 ,4-dioxane, and a base selected from l,8-diazabicyclo[5.4.0]undec-7-ene (DBU), diisopropylethylamine, triethylamine, or l,5-diazabicyclo[4.3.0]non-5-ene (DBN), and stirring at a temperature of from -40°C to 110°C to produce the bis ester of
formula (17) .
Figure imgf000045_0001
R j) adding hydrochloric acid or trifluoroacetic acid (TFA) to a mixture ofthe product from Step i) and a solvent selected from dichloromethane, chloroform, 1 ,4-dioxane, tetrahydrofuran, ethyl ether, and tert-butyl methyl ether, and stirring at a temperature from -40°C to 110°C to produce
the carboxylic acid of formula (18)
Figure imgf000045_0002
R k) adding the product of Step j) to a mixture of a base selected from triethylamine and diisopropylethylamine, a solvent selected from toluene, benzene, xylenes, and «-heptane, and diphenylphosphoryl azide (DPPA), and stirring at a temperature from 0°C to 150°C to produce the isocyanate
of formula (19) ; or adding the product of Step j) above to
Figure imgf000045_0003
R ethyl chloroformate or isobutyl chloroformate, a base selected from triethylamine and diisopropylethylamine, and a solvent selected from tetrahydrofuran, acetone, and diethyl ether at a temperature of from -40°C to 78°C, followed by adding a solution of sodium azide in water and tetrahydrofuran or acetone, followed by adding toluene or benzene, and
refluxing to produce isocyanate of formula (19)
Figure imgf000046_0001
R
1) adding the product of Step k) to a mixture of a solvent selected from toluene, benzene, xylenes, and rc-heptane, and methanol, and stirring at a temperature from 0°C to 150°C to produce the carbamate of formula (20)
Figure imgf000046_0002
m) adding the product of Step 1) to a mixture of a solvent selected from water, acetic acid, and 1 ,4-dioxane, and aqueous hydrochloric acid at a concentration of from 0.01 M to 12 M, and stirring at a temperature from 0°C to 115°C to produce a compound of formula Ila
Figure imgf000046_0003
R n) converting the product of Step m) to a compound of Formula II
5 and further converting, if desired, to a pharmaceutically
Figure imgf000046_0004
acceptable salt by known means. More preferred is a process for the preparation of a compound of Formula II wherein R is Cj-Cι Q alkyl or C3-C10 cycloalkyl, and pharmaceutically acceptable salts thereof, which comprises: a) adding a cyanoacetate of formula (A) NC^ C02R1 , wherein R] is
ethyl, to a mixture of a chiral cyclopentanone of formula (1)
Figure imgf000047_0001
R toluene, acetic acid, and a Knoevenagel reaction catalyst which is ammonium acetate, and heating the mixture at reflux over a Dean-Stark
trap to produce the alkene of formula (2)
Figure imgf000047_0002
R b) adding the product of Step a) above to a mixture of benzylmagnesium chloride in dry tetrahydrofuran at -100°C to 25°C to produce the addition
products of formulas (3a) and
Figure imgf000047_0003
Figure imgf000047_0004
R c) adding the products of Step b) above to a mixture of potassium hydroxide in ethylene glycol and heating the mixture at 100°C to 200°C, and then acidifying to produce the hydrolysis products of formulas
Figure imgf000048_0001
R R d) contacting the products of Step c) above with (S)-α-methyl-benzylamine in ethyl acetate, and recrystallizing the salt so formed from ethyl acetate to
Ph coo-
produce the enriched diastereomer of formula (5)
Figure imgf000048_0002
as the (S)-α-methyl-benzylamine salt; e) adding the product of Step d) to aqueous hydrochloric acid and stirring to
produce the carboxylic acid of formula (6)
Figure imgf000048_0003
f) adding oxalyl chloride to a mixture ofthe product of Step e), dichloromethane, and a catalytic amount of N,N-dimethylformamide
(DMF), and stirring to produce the acid chloride of formula (14)
Figure imgf000048_0004
g) adding the product of Step f) to a mixture of tert-butyl alcohol, dichloromethane, and NN-diisopropylethylamine (DIPEA), and stirring to
produce the ester of formula (15)
Figure imgf000049_0001
R h) adding the product of Step g) to a mixture of carbon tetrachloride or ethyl acetate, and acetonitrile, water, sodium periodate, and ruthenium(III) chloride, and stirring to produce the carboxylic acid of formula (16)
Figure imgf000049_0002
R i) adding the product of Step h) to a mixture of methanol, toluene, and (trimethylsilyl)diazomethane, and stirring to produce the bis ester of
formula (17) . or adding the product of Step h) to a
Figure imgf000049_0003
R mixture of iodomethane, dichloromethane, triethylamine, and stirring to
produce the bis ester of formula (17) .
Figure imgf000049_0004
R j) adding hydrochloric acid or trifluoroacetic acid (TFA) to a mixture of the product from Step i) and dichloromethane, and stirring to produce the
carboxylic acid of formula (18)
Figure imgf000050_0001
k) adding the product of Step j) to a mixture of triethylamine, toluene, and diphenylphosphoryl azide (DPP A), and refluxing to produce the
isocyanate of formula (19) or adding the product of
Figure imgf000050_0002
R
Step j) above to ethyl chloroformate or isobutyl chloroformate, triethylamine, and tetrahydrofuran at a temperature of from -40°C to 78°C, followed by adding a solution of sodium azide in water and tetrahydrofuran or acetone, followed by adding toluene or benzene, and
refluxing to produce isocyanate of formula (19)
Figure imgf000050_0003
R
1) adding the product of Step k) to a mixture of methanol and toluene, and refluxing to produce the carbamate of formula (20)
Figure imgf000050_0004
R m) adding the product of Step 1) to a mixture of 1 ,4-dioxane and aqueous hydrochloric acid at a concentration of 6 M, and stirring to produce a
compound of formula Ila HC1
Figure imgf000051_0001
R n) converting the product of Step m) to a compound of Formula II
5 an further converting, if desired, to a
Figure imgf000051_0002
pharmaceutically acceptable salt by known means. Also preferred is a process for the preparation of a compound of Formula II, further characterized in that the intermediate product (14)
formed is further reacted, without isolation, with tert-butyl alcohol
Figure imgf000051_0003
to produce the ester of formula ( 15)
Figure imgf000051_0004
Also preferred is a process for the preparation of a compound of Formula II, further characterized in that the intermediate product (19) formed is further reacted, without isolation, with methanol to
Figure imgf000052_0001
R
produce the carbamate of formula (20)
Figure imgf000052_0002
R
Also preferred is a process for the preparation of a compound of Formula II, further characterized in that the intermediate product (14)
formed is further reacted, without isolation, with tert-butyl alcohol
Figure imgf000052_0003
to produce the ester of Formula (15) , and the intermediate
Figure imgf000052_0004
product (19) formed is further reacted, without isolation, with
Figure imgf000052_0005
R
methanol to produce the carbamate of formula (20)
Figure imgf000052_0006
R Further, the invention provides a process for the preparation of a compound of Formula III
Figure imgf000053_0001
wherein R is Ci -C^Q alkyl or C3-C1 o cycloalkyl, and pharmaceutically acceptable salts thereof, which comprises: a) adding a cyanoacetate of formula (A) C^/^2 1 , wherein R is alkyl or benzyl, to a mixture of a chiral cyclopentanone of formula (21)
, a solvent, a carboxylic acid, and a Knoevenagel reaction
Figure imgf000053_0002
catalyst, and stirring the mixture in the presence of a means of removing water to produce the alkene of
formula (22)
Figure imgf000053_0003
b) adding the product of Step a) above to a mixture of benzylmagnesium chloride or benzylmagnesium iodide, in a solvent to produce the addition of products of formulas (23a) and (23b)
Figure imgf000054_0001
Figure imgf000054_0002
adding the products of Step b) above to a mixture of a base selected from potassium hydroxide, sodium hydroxide, lithium hydroxide, and cesium hydroxide, in a solvent, and stirring, and then acidifying to produce the
carboxylic acids of formulas (24a) and (24b)
Figure imgf000054_0003
Figure imgf000054_0004
adding the products of Step b) above to an acid mixture, and stirring to
produce the carboxylic acids of formulas (24a)
Figure imgf000054_0005
Figure imgf000054_0006
d) contacting the products of Step c) above with an amine in a solvent, and recrystallizing the salt so formed to produce the enriched diastereomer of
Figure imgf000055_0001
e) converting the product of Step d) to a carboxylic acid of formula (26)
Figure imgf000055_0002
f) adding the product of Step e) to a mixture of iodomethane, a solvent, and l,8-diazabicyclo[5.4.0]undec-7-ene (DBU), and stirring to produce the
ester of formula (27) ; or adding the product of Step e)
Figure imgf000055_0003
to methanol and an acid to produce the ester of formula (27)
or adding the product of Step e) to a solution of
Figure imgf000055_0004
diazomethane or trimethylsilyl-diazomethane in a solvent to produce ester
of formula (27)
Figure imgf000055_0005
g) adding the product of Step f) to a mixture of carbon tetrachloride or ethyl acetate, and acetonitrile, water, sodium periodate, and ruthenium(III) chloride, and stirring to produce the carboxylic acid of formula (28)
Figure imgf000056_0001
h) adding the product of Step g) to a mixture of a tertiary amine base, a solvent, and diphenylphosphoryl azide (DPP A), and stirring to produce the
isocyanate of formula (29) product of
Figure imgf000056_0002
Step g) above to ethyl chloroformate or isobutyl chloroformate and a base in a solvent at a temperature of from -40°C to 78°C, followed by adding a solution of sodium azide in water and tetrahydrofuran or acetone, followed by adding toluene or benzene, and refluxing to produce isocyanate of
formula (29)
Figure imgf000056_0003
i) adding the product of Step h) to a mixture of a solvent and methanol, and stirring to produce the carbamate of formula (30)
Figure imgf000056_0004
j) adding the product of Step i) to a mixture of a solvent and aqueous hydrochloric acid, and stirring to produce a compound of formula (Ilia)
Figure imgf000057_0001
k) converting the product of Step j) to a compound of formula (III)
; an further converting, if desired, to a
Figure imgf000057_0002
pharmaceutically acceptable salt by known means.
This process is outlined in Scheme 4.
Scheme 4
Figure imgf000058_0001
(III) (Ilia) (30)
Preferred is a process for the preparation of a compound of Formula III wherein R is Ci -Ci Q alkyl or C3-C10 cycloalkyl, and pharmaceutically acceptable salts thereof, which comprises: a) adding ethyl cyanoacetate to a mixture of a chiral cyclopentanone of formula (21) in a solvent selected from toluene, benzene, xylenes, or rc-heptane to which acetic acid and β-alanine or ammonium acetate were added, and stirring the mixture at a temperature from 0°C to 150°C to produce the alkene of formula (22); b) adding the product of Step a) above to a mixture of benzylmagnesium chloride in a dry solvent selected from tetrahydrofuran, 1,4-dioxane, n-heptane, toluene, ethyl ether, or tert-butyl methyl ether at a temperature from -100°C to 110°C to produce the addition products of formulas (23a) and (23b); c) adding the products of Step b) above to a mixture of a base selected from potassium hydroxide, sodium hydroxide, lithium hydroxide, or cesium hydroxide in a solvent selected from ethylene glycol, 2-methoxyethyl ether, 1 ,4-dioxane, or diethylene glycol and stirring the mixture at a temperature from 25°C to 250°C to produce the carboxylic acids of formulas (24a) and
(24b); d) contacting the products of Step c) above with (R)-α-mefhyl-benzylamine in a solvent selected from ethyl acetate, acetonitrile, tetrahydrofuran, or 1,4-dioxane at a temperature from -40°C to 105°C, and recrystallizing the salt so formed from a solvent selected from ethyl acetate, acetonitrile, tetrahydrofuran, 1 ,4-dioxane, tert-butyl methyl ether, toluene, or rc-heptane to produce the enriched diastereomer of formula (25a) as the (R)-α-methyl- benzylamine salt; e) adding the product of Step d) to a mixture selected from aqueous hydrochloric acid, hydrochloric acid dissolved in acetic acid, or hydrochloric acid dissolved in acetic acid to which water was added and stirring at a temperature from -40°C to 115°C to produce the carboxylic acid of formula (26); f) adding the product of Step e) to a mixture of iodomethane in a solvent selected from dichloromethane, chloroform, tetrahydrofuran, toluene, or
1,4-dioxane to which l,8-diazabicyclo[5.4.0]undec-7-ene (DBU) was added, and stirring at a temperature from -40°C to 110°C to produce the ester of formula (27); g) adding the product of Step f) to a mixture of carbon tetrachloride and acetonitrile to which water, sodium periodate, and ruthenium(III) chloride were added, and stirring at a temperature from -40°C to 80°C to produce the carboxylic acid of formula (28); h) adding the product of Step g) to a mixture of a base selected from triethylamine or diisopropylethylamine and a solvent selected from toluene, benzene, xylenes, or n-heptane to which diphenylphosphoryl azide (DPPA) was added, and stirring at a temperature from 0°C to 150°C to produce the isocyanate of formula (29); i) adding the product of Step h) to a solvent selected from toluene, benzene, xylenes, or ^-heptane to which methanol was added and stirring at a temperature from 0°C to 150°C to produce the carbamate of formula (30); j) adding the product of Step i) to a solvent selected from water, acetic acid, or 1,4-dioxane to which aqueous hydrochloric acid at a concentration of from
0.01 M to 12 M was added, and stirring at a temperature from 0°C to 115°C to produce a compound of Formula Ilia; k) converting the product of Step j) to a compound of Formula III, and further converting, if desired, to a pharmaceutically acceptable salt by known means.
More preferred is a process for the preparation of a compound of Formula III wherein R is Cj-Ci Q alkyl or C3-C1 o cycloalkyl, and pharmaceutically acceptable salts thereof, which comprises: a) adding ethyl cyanoacetate to a mixture of a chiral cyclopentanone of formula (21) in toluene to which acetic acid and ammonium acetate were added, and heating the mixture at reflux to produce the alkene of formula (22); b) adding the product of Step a) above to a mixture of benzylmagnesium chloride in dry tetrahydrofuran at -100°C to -20°C to produce the addition products of formulas (23a) and (23b); c) adding the products of Step b) above to a mixture of potassium hydroxide in ethylene glycol, and heating the mixture at 100°C to 200°C to produce the hydrolysis products of formulas (24a) and (24b); d) contacting the products of Step c) above with (R)-α-mefhyl-benzylamine in ethyl acetate, and recrystallizing the salt so formed from ethyl acetate to produce the enriched diastereomer of formula (25 a) as the (R)-α-methyl- benzylamine salt; e) adding the product of Step d) to aqueous hydrochloric acid and stirring to produce the carboxylic acid of formula (26); f) adding the product of Step e) to a mixture of iodomethane in dichloromethane to which l,8-diazabicyclo[5.4.0]undec-7-ene (DBU) was added, and stirring to produce the ester of formula (27); g) adding the product of Step f) to a mixture of carbon tetrachloride and acetonitrile to which water, sodium periodate, and ruthenium(III) chloride were added, and stirring to produce the carboxylic acid of formula (28); h) adding the product of Step g) to a mixture of triethylamine and toluene to which diphenylphosphoryl azide (DPP A) was added, and refluxing to produce the isocyanate of formula (29); i) adding the product of Step h) to a mixture of methanol and toluene, and refluxing to produce the carbamate of formula (30); j) adding the product of Step i) to 1,4-dioxane to which aqueous hydrochloric acid at a concentration of 6 M was added, and stirring to produce a compound of Formula Ilia; k) converting the product of Step j) to a compound of Formula III, and further converting, if desired, to a pharmaceutically acceptable salt by known means. Also preferred is a process for the preparation of a compound of
Formula III, further characterized in that the intermediate product (29)
formed is further reacted, without isolation, with methanol to
Figure imgf000061_0001
produce the carbamate of formula (30)
Figure imgf000061_0002
Further, the invention provides a process for the preparation of a compound of Formula IV
Figure imgf000062_0001
wherein R is C]-Cι Q alkyl or C3-C10 cycloalkyl, and pharmaceutically acceptable salts thereof, which comprises: a) adding a cyanoacetate of formula (A) NC^^/^^2 1 , wherein R^ is alkyl or benzyl, to a mixture of a chiral cyclopentanone of formula (21)
a solvent, a carboxylic acid, and a Knoevenagel reaction
Figure imgf000062_0002
catalyst, and stirring the mixture in the presence of a means of removing
water to produce the alkene of formula (22)
Figure imgf000062_0003
b) adding the product of Step a) above to a mixture of benzylmagnesium chloride or benzylmagnesium iodide, in a solvent to produce the addition
of products of formulas (23a) and (23b)
Figure imgf000063_0001
Figure imgf000063_0002
adding the products of Step b) above to a mixture of a base selected from potassium hydroxide, sodium hydroxide, lithium hydroxide, and cesium hydroxide, in a solvent, and stirring, and then acidifying to produce the
carboxylic acids of formulas (24a) (24b)
Figure imgf000063_0003
Figure imgf000063_0004
adding the products of Step b) above to an acid mixture, and stirring to
produce the carboxylic acids of formulas (24a)
Figure imgf000063_0005
Figure imgf000063_0006
d) contacting the products of Step c) above with an amine in a solvent, and recrystallizing the salt so formed to produce the enriched diastereomer of
Figure imgf000064_0001
e) converting the product of Step d) to a carboxylic acid of formula (26)
Figure imgf000064_0002
f) adding the product of Step e) to a mixture of a tertiary amine base, a solvent, and diphenylphosphoryl azide (DPP A) is added, and stirring to
produce the isocyanate of formula (31) ; or adding the
Figure imgf000064_0003
product of Step g) above to ethyl chloroformate or isobutyl chloroformate and a base in a solvent at a temperature of from -40°C to 78°C, followed by adding a solution of sodium azide in water and tetrahydrofuran or acetone, followed by adding toluene or benzene, and refluxing to produce
the isocyanate of formula (31)
Figure imgf000064_0004
g) adding the product of Step f) to a mixture of a solvent and methanol, and
stirring to produce the carbamate of formula (32)
Figure imgf000065_0001
h) adding the product of Step g) to a mixture of carbon tetrachloride or ethyl acetate, and acetonitrile, water, sodium periodate, and ruthenium(III) chloride, and stirring to produce the carboxylic acid of formula (33)
Figure imgf000065_0002
i) adding the product of Step h) to a mixture of a solvent and aqueous hydrochloric acid, and stirring to produce a compound of formula (IVa)
Figure imgf000065_0003
j) converting the product of Step i) to a compound of formula (IV)
, and further converting, if desired, to a pharmaceutically
Figure imgf000065_0004
acceptable salt by known means.
This process is outlined in Scheme 5. Scheme 5
Figure imgf000066_0001
Preferred is a process for the preparation of a compound of Formula IV wherein R is Cj-Ci Q alkyl or C3-C10 cycloalkyl, and pharmaceutically acceptable salts thereof, which comprises: a) adding ethyl cyanoacetate to a mixture of a chiral cyclopentanone of formula (21) in a solvent selected from toluene, benzene, xylenes, or 77-heptane to which acetic acid and β-alanine or ammonium acetate were added, and stirring the mixture at a temperature from 0°C to 150°C to produce the alkene of formula (22); b) adding the product of Step a) above to a mixture of benzylmagnesium chloride in a dry solvent selected from tetrahydrofuran, 1 ,4-dioxane, π-heptane, toluene, ethyl ether, or tert-butyl methyl ether at a temperature from -100°C to 110°C to produce the addition products of formulas (23a) and (23b); c) adding the products of Step b) above to a mixture of a base selected from potassium hydroxide, sodium hydroxide, lithium hydroxide, or cesium hydroxide in a solvent selected from ethylene glycol, 2-methoxyethyl ether, 1 ,4-dioxane, or diethylene glycol and stirring the mixture at a temperature from 25°C to 250°C to produce the carboxylic acids of formulas (24a) and (24b); d) contacting the products of Step c) above with (R)-α-methyl-benzylamine in a solvent selected from ethyl acetate, acetonitrile, tetrahydrofuran, or 1,4-dioxane at a temperature from -40°C to 105°C, and recrystallizing the salt so formed from a solvent selected from ethyl acetate, acetonitrile, tetrahydrofuran, 1 ,4-dioxane, tert-butyl methyl ether, toluene, or rc-heptane to produce the enriched diastereomer of formula (25a) as the (R)-α-methyl- benzylamine salt; e) adding the product of Step d) to a mixture selected from aqueous hydrochloric acid, hydrochloric acid dissolved in acetic acid, or hydrochloric acid dissolved in acetic acid to which water was added and stirring at a temperature from -40°C to 115°C to produce the carboxylic acid of formula
(26); f) adding the product of Step e) to a mixture of a base selected from triethylamine or diisopropylethylamine and a solvent selected from toluene, benzene, xylenes, or ^-heptane to which diphenylphosphoryl azide (DPP A) was added, and stirring at a temperature from 0°C to 150°C to produce the isocyanate of formula (31); g) adding the product of Step f) to a solvent selected from toluene, benzene, xylenes, or rø-heptane to which methanol was added and stirring at a temperature from 0°C to 150°C to produce the carbamate of formula (32); h) adding the product of Step g) to a mixture of carbon tetrachloride and acetonitrile to which water, sodium periodate, and ruthenium(III) chloride were added, and stirring at a temperature from -40°C to 80°C to produce the carboxylic acid of formula (33); i) adding the product of Step h) to a solvent selected from water, acetic acid, or 1,4-dioxane to which aqueous hydrochloric acid at a concentration of from 0.01 M to 12 M was added, and stirring at a temperature from 0°C to 115°C to produce a compound of Formula IVa; j) converting the product of Step i) to a compound of Formula IV, and further converting, if desired, to a pharmaceutically acceptable salt by known means. More preferred is a process for the preparation of a compound of
Formula IV wherein R is Ci -Ci Q alkyl or C3-C10 cycloalkyl, and pharmaceutically acceptable salts thereof, which comprises: a) adding ethyl cyanoacetate to a mixture of a chiral cyclopentanone of formula (21) in toluene to which acetic acid and ammonium acetate were added, and heating the mixture at reflux to produce the alkene of formula (22); b) adding the product of Step a) above to a mixture of benzylmagnesium chloride in dry tetrahydrofuran at -100°C to -20°C to produce the addition products of formulas (23a) and (23b); c) adding the products of Step b) above to a mixture of potassium hydroxide in ethylene glycol, and heating the mixture at 100°C to 200°C to produce the hydrolysis products of formulas (24a) and (24b); d) contacting the products of Step c) above with (R)-α-methyl-benzylamine in ethyl acetate, and recrystallizing the salt so formed from ethyl acetate to produce the enriched diastereomer of formula (25a) as the (R)-α-methyl- benzylamine salt; e) adding the product of Step d) to aqueous hydrochloric acid and stirring to produce the carboxylic acid of formula (26); f) adding the product of Step e) to a mixture of triethylamine and toluene to which diphenylphosphoryl azide (DPP A) was added, and refluxing to produce the isocyanate of formula (31 ); g) adding the product of Step f) to a mixture of methanol and toluene, and refluxing to produce the carbamate of formula (32); h) adding the product of Step g) to a mixture of carbon tetrachloride and acetonitrile to which water, sodium periodate, and ruthenium(III) chloride were added, and stirring to produce the carboxylic acid of formula (33); i) adding the product of Step h) to 1 ,4-dioxane to which aqueous hydrochloric acid at a concentration of 6 M was added, and stirring to produce a compound of Formula IVa; j) converting the product of Step i) to a compound of Formula IV, and further converting, if desired, to a pharmaceutically acceptable salt by known means. Also preferred is a process for the preparation of a compound of
Formula IV, further characterized in that the intermediate product (31 )
formed is further reacted, without isolation, with methanol to
Figure imgf000069_0001
produce the carbamate of formula (32)
Figure imgf000069_0002
Still further, the invention provides a process for the preparation of a compound of Formula IV
Figure imgf000069_0003
wherein R is Ci -Ci Q alkyl or C3-C1 Q cycloalkyl, and pharmaceutically acceptable salts thereof, which comprises: a) adding a cyanoacetate of formula (A) NC^^/^-^ 1 , wherein R\ is alkyl or benzyl, to a mixture of a chiral cyclopentanone of formula (21) , a solvent, a carboxylic acid, and a Knoevenagel reaction
Figure imgf000070_0001
catalyst, and stirring the mixture in the presence of a means of removing
water to produce the alkene of formula (22)
Figure imgf000070_0002
b) adding the product of Step a) above to a mixture of benzylmagnesium chloride or benzylmagnesium iodide, in a solvent to produce the addition
of products of formulas (23a) and (23b)
Figure imgf000070_0003
Figure imgf000070_0004
c) adding the products of Step b) above to a mixture of a base selected from potassium hydroxide, sodium hydroxide, lithium hydroxide, and cesium hydroxide, in a solvent, and stirring, and then acidifying to produce the
carboxylic acids of formulas (24a) and (24b)
Figure imgf000071_0001
Figure imgf000071_0002
adding the products of Step b) above to an acid mixture, and stirring to
produce the carboxylic acids of formulas (24a)
Figure imgf000071_0003
Figure imgf000071_0004
d) contacting the products of Step c) above with an amine in a solvent, and recrystallizing the salt so formed to produce the enriched diastereomer of
formula (25) as he amine salt; and
Figure imgf000071_0005
e) converting the product of Step d) to a carboxylic acid of formula (26)
Figure imgf000071_0006
f) adding oxalyl chloride to a mixture ofthe product of Step e), a solvent, and N,N-dimethylformamide (DMF), and stirring to produce the acid chloride
of formula (34)
Figure imgf000072_0001
g) adding the product of Step f) to a mixture of tert-butyl alcohol, a solvent, and a tertiary amine base, and stirring to produce the ester of formula (35)
Figure imgf000072_0002
h) adding the product of Step g) to a mixture of carbon tetrachloride or ethyl acetate, and acetonitrile, water, sodium periodate, and ruthenium(III) chloride, and stirring to produce the carboxylic acid of formula (36)
Figure imgf000072_0003
i) adding the product of Step h) to a mixture of a solvent, methanol, and (trimethylsilyl)diazomethane, and stirring to produce the bis ester of
formula (37) . or adding the product of Step h) to a
Figure imgf000072_0004
mixture of iodomethane, a solvent, and a base, and stirring to produce the
bis ester of formula (37)
Figure imgf000073_0001
j) adding an acid to a mixture ofthe product from Step i) and a solvent and
stirring to produce the carboxylic acid of formula (38) .
Figure imgf000073_0002
k) adding the product of Step j) to a mixture of a tertiary amine base, a solvent, and diphenylphosphoryl azide (DPP A), and stirring to produce the
isocyanate of formula (39) ; or adding the product of
Figure imgf000073_0003
Step j) above to ethyl chloroformate or isobutyl chloroformate and a base in a solvent at a temperature of from -40°C to 78°C, followed by adding a solution of sodium azide in water and tetrahydrofuran or acetone, followed by adding toluene or benzene, and refluxing to produce isocyanate of
formula (39)
Figure imgf000073_0004
1) adding the product of Step k) to a mixture of a solvent and methanol, and
stirring to produce the carbamate of formula (40)
Figure imgf000074_0001
m) adding the product of Step 1) to a mixture of a solvent and hydrochloric acid, and stirring to produce a compound of formula (IVa)
Figure imgf000074_0002
n) converting the product of Step m) to a compound of Formula IV
and further converting, if desired, to a pharmaceutically
Figure imgf000074_0003
acceptable salt by known means.
This process is outlined in Scheme 6.
Scheme 6
Figure imgf000075_0001
(21) (22) (23a) (23b)
Figure imgf000075_0002
(26) (34) (35) (36)
Figure imgf000075_0003
(39) (38) (37)
Figure imgf000075_0004
(40) (IVa) (IV)
Preferred is a process for the preparation of a compound of Formula IV wherein R is Cj-Ci Q alkyl or C3-C10 cycloalkyl, and pharmaceutically acceptable salts thereof, which comprises: a) adding ethyl cyanoacetate to a mixture of a chiral cyclopentanone of formula (21) in a solvent selected from toluene, benzene, xylenes, or n-heptane to which acetic acid and β-alanine or ammonium acetate were added, and stirring the mixture at a temperature from 0°C to 150°C to produce the alkene of formula (22); b) adding the product of Step a) above to a mixture of benzylmagnesium chloride in a dry solvent selected from tetrahydrofuran, 1,4-dioxane, ^-heptane, toluene, ethyl ether, or tert-butyl methyl ether at a temperature from -100°C to 110°C to produce the addition products of formulas (23a) and (23b); c) adding the products of Step b) above to a mixture of a base selected from potassium hydroxide, sodium hydroxide, lithium hydroxide, or cesium hydroxide in a solvent selected from ethylene glycol, 2-methoxyethyl ether, 1 ,4-dioxane, or diethylene glycol and stirring the mixture at a temperature from 25°C to 250°C to produce the carboxylic acids of formulas (24a) and
(24b); d) contacting the products of Step c) above with (R)- -methyl-benzylamine in a solvent selected from ethyl acetate, acetonitrile, tetrahydrofuran, or 1,4-dioxane at a temperature from -40°C to 105°C, and recrystallizing the salt so formed from a solvent selected from ethyl acetate, acetonitrile, tetrahydrofuran, 1 ,4-dioxane, tert-butyl methyl ether, toluene, or «-heptane to produce the enriched diastereomer of formula (25a) as the (R)-α-methyl- benzylamine salt; e) adding the product of Step d) to a mixture selected from aqueous hydrochloric acid, hydrochloric acid dissolved in acetic acid, or hydrochloric acid dissolved in acetic acid to which water was added and stirring at a temperature from -40°C to 115°C to produce the carboxylic acid of formula (26); f) adding oxalyl chloride to a mixture of the product of Step e) and a solvent selected from dichloromethane, chloroform, ethyl ether, toluene, or tert- butyl methyl ether to which 0.01 mol percent to 10 mol percent of N,N- dimethylformamide (DMF) was added, and stirring at a temperature from -40°C to 1 10°C to produce the acid chloride of formula (34); g) adding the product of Step f) to a mixture of tert-butyl alcohol in a solvent selected from dichloromethane, chloroform, ethyl ether, toluene, or tert- butyl methyl ether to which NN-diisopropylethylamine (DIPEA) or triethylamine was added, and stirring at a temperature from -40°C to 110°C to produce the ester of formula (35); h) adding the product of Step g) to a mixture of carbon tetrachloride and acetonitrile to which water, sodium periodate, and ruthenium(III) chloride were added, and stirring at a temperature from -40°C to 80°C to produce the carboxylic acid of formula (36); i) adding the product of Step h) to a solvent selected from toluene, benzene, xylenes, or «-heptane to which methanol and (trimethylsilyl)diazomethane were added, and stirring at a temperature from 0°C to 150°C to produce the bis ester of formula (37); j) adding trifluoroacetic acid (TFA) to a mixture of the product from Step i) and a solvent selected from dichloromethane, chloroform, 1 ,4-dioxane, tetrahydrofuran, ethyl ether, or tert-butyl methyl ether and stirring at a temperature from -40°C to 110°C to produce the carboxylic acid of formula (38); k) adding the product of Step j) to a mixture of a base selected from triethylamine or diisopropylethylamine and a solvent selected from toluene, benzene, xylenes, or w-heptane to which diphenylphosphoryl azide (DPP A) was added, and stirring at a temperature from 0°C to 150°C to produce the isocyanate of formula (39);
1) adding the product of Step k) to a solvent selected from toluene, benzene, xylenes, or ^-heptane to which methanol was added and stirring at a temperature from 0°C to 150°C to produce the carbamate of formula (40); m) adding the product of Step 1) to a solvent selected from water, acetic acid, or 1 ,4-dioxane to which aqueous hydrochloric acid at a concentration of from
0.01 M to 12 M was added, and stirring at a temperature from 0°C to 115°C to produce a compound of Formula IVa; n) converting the product of Step m) to a compound of Formula IV, and further converting, if desired, to a pharmaceutically acceptable salt by known means. More preferred is a process for the preparation of a compound of Formula IV wherein R is Ci -CJ O alkyl or C3-C10 cycloalkyl, and pharmaceutically acceptable salts thereof, which comprises: a) adding ethyl cyanoacetate to a mixture of a chiral cyclopentanone of formula
(21) in toluene to which acetic acid and ammonium acetate were added, and heating the mixture at reflux to produce the alkene of formula (22); b) adding the product of Step a) above to a mixture of benzylmagnesium chloride in dry tetrahydrofuran at -100°C to -20°C to produce the addition products of formulas (23a) and (23b); c) adding the products of Step b) above to a mixture of potassium hydroxide in ethylene glycol, and heating the mixture at 100°C to 200°C to produce the hydrolysis products of formulas (24a) and (24b); d) contacting the products of Step c) above with (R)-α-methyl-benzylamine in ethyl acetate, and recrystallizing the salt so formed from ethyl acetate to produce the enriched diastereomer of formula (25a) as the (R)-α-methyl- benzylamine salt; e) adding the product of Step d) to aqueous hydrochloric acid and stirring to produce the carboxylic acid of formula (26); f) adding oxalyl chloride to a mixture ofthe product of Step e) and dichloromethane to which a catalytic amount of N,N-dimethylformamide
(DMF) was added, and stirring to produce the acid chloride of formula (34); g) adding the product of Step f) to a mixture of tert-butyl alcohol in dichloromethane to which NN-diisopropylethylamine (DIPEA) was added, and stirring to produce the ester of formula (35); h) adding the product of Step g) to a mixture of carbon tetrachloride and acetonitrile to which water, sodium periodate, and ruthenium(III) chloride were added, and stirring to produce the carboxylic acid of formula (36); i) adding the product of Step h) to a mixture of methanol and toluene to which (trimethylsilyl)diazomethane was added, and stirring to produce the bis ester of formula (37); j) adding trifluoroacetic acid (TFA) to a mixture ofthe product from Step i) and dichloromethane, and stirring to produce the carboxylic acid of formula
(38); k) adding the product of Step j) to a mixture of triethylamine and toluene to which diphenylphosphoryl azide (DPP A) was added, and refluxing to produce the isocyanate of formula (39); 1) adding the product of Step k) to a mixture of methanol and toluene, and refluxing to produce the carbamate of formula (40); m) adding the product of Step 1) to 1 ,4-dioxane to which aqueous hydrochloric acid at a concentration of 6 M was added, and stirring to produce a compound of Formula IVa; n) converting the product of Step m) to a compound of Formula IV, and further converting, if desired, to a pharmaceutically acceptable salt by known means. Also preferred is a process for the preparation of a compound of Formula IV, further characterized in that the intermediate product (34)
formed is further reacted, without isolation, with tert-butyl alcohol
Figure imgf000079_0001
to produce the ester of formula (35)
Figure imgf000079_0002
Also preferred is a process for the preparation of a compound of Formula IV, further characterized in that the intermediate product (39) formed is further reacted, without isolation, with methanol to
Figure imgf000080_0001
produce the carbamate of formula (40)
Figure imgf000080_0002
Also preferred is a process for the preparation of a compound of Formula IV, further characterized in that the intermediate product (34)
formed is further reacted, without isolation, with tert-butyl alcohol
Figure imgf000080_0003
to produce the ester of formula (35) ntermediate
Figure imgf000080_0004
product (39) formed is further reacted, without isolation, with
Figure imgf000080_0005
methanol to produce the carbamate of formula (40)
Figure imgf000080_0006
Further, the invention provides a process for the preparation of a compound of formula (6)
Figure imgf000081_0001
R wherein R is Ci -Ci Q alkyl or C3-C1 Q cycloalkyl, and pharmaceutically acceptable salts thereof, which comprises: a) adding a cyanoacetate of formula (A) NC ^/^υ2 1 , wherein R\ is alkyl or benzyl, to a mixture of a chiral cyclopentanone of formula (1)
, a solvent, a carboxylic acid, and a Knoevenagel reaction
Figure imgf000081_0002
catalyst, and stirring the mixture in the presence of a means of removing
water to produce the alkene of formula
Figure imgf000081_0003
R b) adding the product of Step a) above to a mixture of benzylmagnesium chloride, benzylmagnesium bromide, or benzylmagnesium iodide, in a solvent to produce the addition products of formulas (3 a)
Figure imgf000081_0004
c) adding the products of Step b) above to a mixture of a base selected from potassium hydroxide, sodium hydroxide, lithium hydroxide, and cesium hydroxide, and a solvent, and stirring, and then acidifying to produce the carboxylic acids of formulas (4a) and (4b)
Figure imgf000082_0001
R
Figure imgf000082_0002
R adding the products of Step b) above to an acid mixture and stirring to
produce the carboxylic acids of formulas (4a) (4b)
Figure imgf000082_0003
R
Figure imgf000082_0004
R contacting the products of Step c) above with an amine in a solvent, and recrystallizing the salt so formed to produce the enriched diastereomer of
formula (5) the amine salt; and
Figure imgf000082_0005
converting the product of Step d) to a carboxylic acid of formula (6)
Figure imgf000082_0006
This process is outlined in Scheme 7.
Scheme 7
Figure imgf000083_0001
(1 ) (2) (3a) (3b)
Figure imgf000083_0002
(4a) (4b)
Amine
Figure imgf000083_0003
(6) (5)
Preferred is a process for the preparation of a compound of formula (6) wherein R is Ci -Ci Q alkyl or C3-C10 cycloalkyl, and pharmaceutically acceptable salts thereof, which comprises: a) adding a cyanoacetate of formula (A)
Figure imgf000083_0004
wherein Ri is selected from methyl, ethyl, «-propyl, z'so-propyl, «-butyl, iso-butyl, sec-butyl, tert-butyl, and benzyl to a mixture of a chiral cyclopentanone of
formula (1) , a solvent selected from tetrahydrofuran, 1 ,4-
Figure imgf000083_0005
R dioxane, tert-butylmethylether, chloroform, dichloromethane, acetonitrile, ethyl ether, ethyl acetate, hexanes, N,N-dimethylformamide, dimethylsulfoxide, ethanol, tcrt-butanol, toluene, benzene, xylenes, and «-heptane, acetic acid, and a Knoevenagel reaction catalyst selected from β-alanine, ammonium acetate, and piperidine, and stirring the mixture in the presence of a means of removing water selected from azeotropic distillation, activated molecular sieves, anhydrous magnesium sulfate, anhydrous sodium sulfate, anhydrous sodium carbonate, anhydrous potassium carbonate, anhydrous cesium carbonate, trimethyl orthoformate, and triethyl orthoformate to produce the alkene of formula (2)
Figure imgf000084_0001
R b) adding the product of Step a) above to a mixture of benzylmagnesium chloride, benzylmagnesium bromide, or benzylmagnesium iodide in a solvent selected from tetrahydrofuran, benzene, 1 ,4-dioxane, hexanes, ^-heptane, toluene, diethyl ether, and tert-butyl methyl ether to produce
the addition products of formulas (3 a) and (3b)
Figure imgf000084_0002
Figure imgf000084_0003
c) adding the products of Step b) above to a mixture of a base selected from potassium hydroxide, sodium hydroxide, lithium hydroxide, and cesium hydroxide in a solvent selected from ethylene glycol, 2-methoxyethyl ether, 1 ,4-dioxane, and diethylene glycol, and stirring the mixture, and then acidifying to produce the carboxylic acids of formulas (4a) and (4b) ; 0r adding the products of
Figure imgf000085_0002
Figure imgf000085_0001
R R
Step b) above to an acid mixture selected from 6-12 M HCl, 12 M H2SO4, 10%-48% wt/wt hydrobromic acid, and HBr in aqueous acetic acid, and
stirring to produce the carboxylic acids of formulas (4a)
Figure imgf000085_0003
R
Figure imgf000085_0004
R contacting the products of Step c) above with an amine selected from (S)-α-methyl-benzylamine, (R)- -methyl-benzylamine, (R)-(+)-l- (naphthyl)ethylamine, (S)-(+)- 1 -(naphthyl)ethylamine, triethylamine, diisopropylethylamine, dicyclohexylamine, benzylamine, dibenzylamine, morpholine, N-methylmorpholine, piperidine, N-methylpiperidine, and pyridine in a solvent selected from N,N-dimethylformamide, chloroform, benzene, xylenes, hexanes, acetone, ethanol, methanol, /so-propanol, diethyl ether, dichloromethane, benzene, toluene, n-pentane, n-hexane, n-heptane, ethyl acetate, acetonitrile, tert-butyl methyl ether, tetrahydrofuran, and 1 ,4-dioxane, and recrystallizing the salt so formed to
produce the enriched diastereomer of formula (5)
Figure imgf000085_0005
as the amine salt; and e) adding the product of Step d) to a mixture selected from aqueous hydrochloric acid, aqueous sulfuric acid, aqueous acetic acid, hydrochloric acid dissolved in acetic acid, and hydrochloric acid dissolved in acetic acid and water, and stirring to produce the carboxylic acid of formula (6)
Figure imgf000086_0001
partitioning the product of Step d) between a mixture of aqueous hydrochloric acid and a solvent selected from chloroform, dichloromethane, ethyl acetate, ethyl ether, tetrahydrofuran, 1 ,4-dioxane, toluene, and tert-butylmethylether, and drying and evaporating the organic
layer to produce the carboxylic acid of formula (6)
Figure imgf000086_0002
More preferred is a process for the preparation of a compound of formula (6) wherein R is Ci -Ci Q alkyl or C3-C1 Q cycloalkyl, and pharmaceutically acceptable salts thereof, which comprises: a) adding a cyanoacetate of formula (A)
Figure imgf000086_0003
vs>
ethyl, to a mixture of a chiral cyclopentanone of formula (1 )
Figure imgf000086_0004
R toluene, acetic acid, and a Knoevenagel reaction catalyst which is ammonium acetate, and heating the mixture at reflux over a Dean-Stark
trap to produce the alkene of formula (2)
Figure imgf000087_0001
R b) adding the product of Step a) above to a mixture of benzylmagnesium chloride in dry tetrahydrofuran at -100°C to 25°C to produce the addition
products of formulas (3a) and
Figure imgf000087_0002
R
Figure imgf000087_0003
c) adding the products of Step b) above to a mixture of potassium hydroxide in ethylene glycol, and heating the mixture at 100°C to 200°C, and then acidifying to produce the hydrolysis products of formulas (4a)
Figure imgf000087_0004
R R d) contacting the products of Step c) above with (S)-α-methyl-benzylamine in ethyl acetate, and recrystallizing the salt so formed from ethyl acetate to produce the enriched diastereomer of formula (5)
Figure imgf000088_0001
as the (S)-α-methyl-benzylamine salt; e) adding the product of Step d) to aqueous hydrochloric acid and stirring to
produce the carboxylic acid of formula (6)
Figure imgf000088_0002
Further, the invention provides a process for the preparation of a compound of formula (26)
Figure imgf000088_0003
wherein R is C J -CJ O alkyl or C3-C10 cycloalkyl, and pharmaceutically acceptable salts thereof, which comprises: a) adding a cyanoacetate of formula (A) NC ^/',-'u2 1 , wherein R\ is alkyl or benzyl, to a mixture of a chiral cyclopentanone of formula (21)
, a solvent, a carboxylic acid, and a Knoevenagel reaction
Figure imgf000088_0004
catalyst, and stirring the mixture in the presence of a means of removing
water to produce the alkene of formula (22)
Figure imgf000089_0001
b) adding the product of Step a) above to a mixture of benzylmagnesium chloride or benzylmagnesium iodide, in a solvent to produce the addition
of products of formulas (23a) and (23b)
Figure imgf000089_0002
Figure imgf000089_0003
c) adding the products of Step b) above to a mixture of a base selected from potassium hydroxide, sodium hydroxide, lithium hydroxide, and cesium hydroxide, and a solvent, and stirring, and then acidifying to produce the
carboxylic acids of formulas (24a) (24b)
Figure imgf000089_0004
Figure imgf000089_0005
adding the products of Step b) above to an acid mixture, and stirring to
produce the carboxylic acids of formulas (24a)
Figure imgf000090_0001
Figure imgf000090_0002
d) contacting the products of Step c) above with an amine in a solvent, and recrystallizing the salt so formed to produce the enriched diastereomer of
formula (25) as the amine salt; and
Figure imgf000090_0003
e) converting the product of Step d) to a carboxylic acid of formula (26)
Figure imgf000090_0004
This process is outlined in Scheme 8.
Scheme 8
Figure imgf000091_0001
Amine
Figure imgf000091_0002
(26) (25)
Preferred is a process for the preparation of a compound of formula (26) wherein R is Ci -CJ O alkyl or C3-C1 Q cycloalkyl, and pharmaceutically acceptable salts thereof, which comprises: a) adding a cyanoacetate of formula (A) NC^/" 2 1 , wherein R is selected from methyl, ethyl, «-propyl, z'so-propyl, rø-butyl, z'so-butyl, sec-butyl, tert-butyl, and benzyl, to a mixture of a chiral cyclopentanone of
formula (21) a solvent selected from tetrahydrofuran, 1 ,4-
Figure imgf000091_0003
dioxane, tert-butylmethylether, chloroform, dichloromethane, acetonitrile, ethyl ether, ethyl acetate, hexanes, N,N-dimethylformamide, dimethylsulfoxide, ethanol, tert-butanol, toluene, benzene, xylenes, and ^-heptane, acetic acid, and a Knoevenagel reaction catalyst selected from β-alanine, ammonium acetate, and piperidine, and stirring the mixture in the presence of a means of removing water selected from azeotropic distillation, activated molecular sieves, anhydrous magnesium sulfate, anhydrous cesium carbonate, trimethyl orthoformate, and triethyl
orthoformate to produce the alkene of formula (22)
Figure imgf000092_0001
b) adding the product of Step a) above to a mixture of benzylmagnesium chloride, benzylmagnesium bromide, or benzylmagnesium iodide in a solvent selected from tetrahydrofuran, 1 ,4-dioxane, hexanes, rø-heptane, toluene, diethyl ether, and tert-butyl methyl ether to produce the addition
products of formulas (23a) and (23b)
Figure imgf000092_0002
Figure imgf000092_0003
c) adding the products of Step b) above to a mixture of a base selected from potassium hydroxide, sodium hydroxide, lithium hydroxide, and cesium hydroxide in a solvent selected from ethylene glycol, 2-methoxyethyl ether, 1 ,4-dioxane, and diethylene glycol, and stirring the mixture, and then acidifying to produce the carboxylic acids of formulas (24a)
Figure imgf000092_0004
adding the products of Step b) above to an acid mixture selected from 6-12 M HCl, 12 M H2SO4, 10%-48% wt/wt hydrobromic acid, and HBr in aqueous acetic acid, and stirring to produce the carboxylic acids of
formulas (24a) and (24b)
Figure imgf000093_0001
Figure imgf000093_0002
d) contacting the products of Step c) above with an amine selected from (S)- α-methyl-benzylamine, (R)-α-methyl-benzylamine, (R)-(+)-l- (naphthyl)ethylamine, (S)-(+)-l-(naphthyl)ethylamine, triethylamine, diisopropylethylamine, dicyclohexylamine, benzylamine, dibenzylamine, morpholine, N-methylmorpholine, piperidine, N-methylpiperidine, and pyridine in a solvent selected from N,N-dimethylformamide, chloroform, hexanes, acetone, ethanol, methanol, zso-propanol, diethyl ether, dichloromethane, benzene, toluene, n-pentane, n-hexane, n-heptane, ethyl acetate, acetonitrile, tert-butyl methyl ether, tetrahydrofuran, and 1 ,4- dioxane, and recrystallizing the salt so formed to produce the enriched
Figure imgf000093_0003
and e) adding the product of Step d) to a mixture selected from aqueous hydrochloric acid, aqueous sulfuric acid, aqueous acetic acid, hydrochloric acid dissolved in acetic acid, and hydrochloric acid dissolved in acetic acid and water, and stirring to produce the carboxylic acid of formula (26)
Figure imgf000093_0004
partitioning the product of Step d) between a mixture of aqueous hydrochloric acid and a solvent selected from chloroform, dichloromethane, ethyl acetate, ethyl ether, tetrahydrofuran, 1 ,4-dioxane, toluene, and tert-butylmethylether, and drying and evaporating the organic
layer to produce the carboxylic acid of formula (26)
Figure imgf000094_0001
More preferred is a process for the preparation of a compound of formula (26) wherein R is Ci -CJ O alkyl or C3-C1 Q cycloalkyl, and pharmaceutically acceptable salts thereof, which comprises: a) adding a cyanoacetate of formula (A) NCV^/-'L''J2 1 , wherein Ri is
ethyl, to a mixture of a chiral cyclopentanone of formula (21 )
Figure imgf000094_0002
toluene, acetic acid, and a Knoevenagel reaction catalyst which is ammonium acetate, and heating the mixture at reflux over a Dean-Stark
trap to produce the alkene of formula (22)
Figure imgf000094_0003
b) adding the product of Step a) above to a mixture of benzylmagnesium chloride in dry tetrahydrofuran at -100°C to -20°C to produce the addition products of formulas (23 a) and (23b)
Figure imgf000095_0001
Figure imgf000095_0002
c) adding the products of Step b) above to a mixture of potassium hydroxide in ethylene glycol, and heating the mixture at 100°C to 200°C, and then acidifying to produce the hydrolysis products of formulas (24a)
Figure imgf000095_0003
d) contacting the products of Step c) above with (R)-α-methyl-benzylamine in ethyl acetate, and recrystallizing the salt so formed from ethyl acetate to produce the enriched diastereomer of formula (25)
as the (R)-α-methyl-benzylamine salt; and
Figure imgf000095_0004
e) adding the product of Step d) to aqueous hydrochloric acid and stirring to
produce the carboxylic acid of formula (26)
Figure imgf000095_0005
Further, the invention provides a key intermediate of formula (6)
Figure imgf000096_0001
R wherein R is Ci -Ci Q alkyl or C3-C1 Q cycloalkyl, and pharmaceutically acceptable salts thereof.
Preferred is a compound of formula (6) and pharmaceutically acceptable salts thereof wherein R is CI -CJ Q alkyl.
More preferred is a compound of formula (6) and pharmaceutically acceptable salts thereof wherein R is selected from methyl, ethyl, and n-propyl.
Still more preferred is a compound of formula (6) named ((1S,3R)-1- benzy 1-3 -methyl-cyclopenty l)-acetic acid. Further, the invention provides a key intermediate of formula (26)
Figure imgf000096_0002
wherein R is Cj-Ci Q alkyl or C3-C1 Q cycloalkyl and pharmaceutically acceptable salts thereof.
Preferred is a compound of formula (26) and pharmaceutically acceptable salts thereof wherein R is C \ -C \ Q alkyl .
More preferred is a compound of formula (26) and pharmaceutically acceptable salts thereof wherein R is selected from methyl, ethyl, and n-propyl.
Still more preferred is a compound of formula (26) named ((1R,3S)-1- benzyl-3-methyl-cyclopentyl)-acetic acid. Further, the invention provides a compound of Formula I, wherein R is as defined above, prepared according to any one ofthe processes for the preparation of a compound of Formula I described above. Preferred is a compound of Formula I, wherein R is CJ -CI Q alkyl, prepared according to any one ofthe processes for the preparation of a compound of Formula I described above.
More preferred is a compound of Formula I, wherein R is selected from methyl, ethyl, and w-propyl, prepared according to any one ofthe processes for the preparation of a compound of Formula I described above.
Still more preferred is a compound of Formula I selected from: ((lR,3S)-l-aminomethyl-3-methyl-cyclopentyl)-acetic acid; and ((lR,3S)-l-aminomethyl-3-methyl-cyclopentyl)-acetic acid hydrochloride, prepared according to any one ofthe processes for the preparation of a compound of Formula I described above.
Further, the invention provides a compound of Formula II, wherein R is as defined above, prepared according to any one ofthe processes for the preparation of a compound of Formula II described above. Preferred is a compound of Formula II, wherein R is C \ -C \ o alkyl, prepared according to any one ofthe processes for the preparation of a compound of Formula II described above.
More preferred is a compound of Formula II, wherein R is selected from methyl, ethyl, and «-propyl, prepared according to any one ofthe processes for the preparation of a compound of Formula II described above.
Still more preferred is a compound of Formula II selected from: ((lS,3R)-l-aminomethyl-3-methyl-cyclopentyl)-acetic acid; and ((1 S,3R)-l-aminomethyl-3-methyl-cyclopentyl)-acetic acid hydrochloride, prepared according to any one ofthe processes for the preparation of a compound of Formula II described above.
Further, the invention provides a compound of Formula III, wherein R is as defined above, prepared according to any one ofthe processes for the preparation of a compound of Formula III described above.
Further, the invention provides a compound of Formula IV, wherein R is as defined above, prepared according to any one ofthe processes for the preparation of a compound of Formula IV described above. Further, the invention provides a compound of formula (6), wherein R is as defined above, prepared according to any one ofthe processes for the preparation of a compound of formula (6) described above.
Preferred is a compound of formula (6), wherein R is Ci -Ci Q alkyl, prepared according to any one ofthe processes for the preparation of a compound of formula (6) described above.
More preferred is a compound of formula (6), wherein R is selected from methyl, ethyl, and rc-propyl, prepared according to any one ofthe processes for the preparation of a compound of formula (6) described above. Still more preferred is a compound of formula (6) named
((lS,3R)-l-benzyl-3-methyl-cyclopentyl)-acetic acid, prepared according to any one ofthe processes for the preparation of a compound of formula (6) described above.
Further, the invention provides a compound of formula (26), wherein R is as defined above, prepared according to any one ofthe processes for the preparation of a compound of formula (26) described above.
Preferred is a compound of formula (26), wherein R is Ci -C J Q alkyl, prepared according to any one ofthe processes for the preparation of a compound of formula (26) described above. More preferred is a compound of formula (26), wherein R is selected from methyl, ethyl, and /7-propyl, prepared according to any one ofthe processes for the preparation of a compound of formula (26) described above.
Still more preferred is a compound of formula (26) named
((lR,3S)-l-benzyl-3-methyl-cyclopentyl)-acetic acid, prepared according to any one ofthe processes for the preparation of a compound of formula (26) described above.
Further, the invention provides a compound of Formula I selected from:
(( 1 R,3R)- 1 -aminomethyl-3 -methyl-cyclopentyl)-acetic acid;
((lR,3R)-l-aminomethyl-3-methyl-cyclopentyl)-acetic acid hydrochloride; ((lR,3R)-l-aminomethyl-3-ethyl-cyclopentyl)-acetic acid;
((1R,3R)-1 -aminomethyl-3 -ethyl -cyclopentyl)-acetic acid hydrochloride;
((lR,3R)-l-aminomethyl-3-propyl-cyclopentyl)-acetic acid; and ((lR,3R)-l-aminomethyl-3-propyl-cyclopentyl)-acetic acid hydrochloride. Further, the invention provides a compound of Formula II selected from: ((lS,3R)-l-aminomethyl-3-methyl-cyclopentyl)-acetic acid; ((1 S,3R)-1 -aminomethyl-3-methyl-cyclopentyl)-acetic acid hydrochloride; ((lS,3R)-l-aminomethyl-3-ethyl-cyclopentyl)-acetic acid;
((1 S,3R)-l-aminomethyl-3-ethyl-cyclopentyl)-acetic acid hydrochloride; ((lS,3R)-l-aminomethyl-3-propyl-cyclopentyl)-acetic acid; and ((1 S,3R)-1 -aminomethyl-3-propyl-cyclopentyl)-acetic acid hydrochloride. Further, the invention provides compounds selected from: E-Cyano-((R)-3-methyl-cyclopentylidene)-acetic acid ethyl ester;
Z-Cyano-((R)-3-methyl-cyclopentylidene)-acetic acid ethyl ester; (R)-((l S,3R)-1 -Benzyl-3-methyl-cyclopentyl)-cyano-acetic acid ethyl ester;
(S)-((l S,3R)-1 -Benzyl-3-methyl-cyclopentyl)-cyano-acetic acid ethyl ester;
(R)-((1R,3R)-1 -Benzyl-3-methyl-cyclopentyl)-cyano-acetic acid ethyl ester;
(S)-((1R,3R)-1 -Benzyl-3-methyl-cyclopentyl)-cyano-acetic acid ethyl ester; ((1 S,3R)- 1 -Isocyanatomethyl-3-methyl-cyclopentylmethyl)-benzene;
((1 S,3R)-l-Benzyl-3-methyl-cyclopentylmethyl)-carbamic acid methyl ester;
[(l S,3R)-l-(Methoxycarbonylamino-methyl)-3-methyl-cyclopentyl]-acetic acid; ((1 S,3R)-1 -Benzyl-3-methyl-cyclopentyl)-acetic acid methyl ester;
(lS,3R)-l-Methoxycarbonylmethyl-3-methyl-cyclopentyl)-acetic acid;
((lR,3R)-l-Isocyanatomethyl-3-methyl-cyclopentyl)-acetic acid methyl ester;
[(lR,3R)-l-(Methoxycarbonylamino-methyl)-3-methyl-cyclopentyl]-acetic acid methyl ester;
((lS,3R)-l-Benzyl-3-methyl-cyclopentyl)-acetic acid tert-butyl ester;
[(lS,3R)-l-Carboxymethyl-3-methyl-cyclopentyl]-acetic acid tert-butyl ester; [( 1 S ,3 R)- 1 -Methoxycarbonylmethyl-3 -methyl-cyclopentyl] -acetic acid tert-butyl ester;
((lR,3R)-l-Methoxycarbonylmethyl-3-methyl-cyclopentyl)-acetic acid; ((lS,3R)-l-Isocyanatomethyl-3-methyl-cyclopentyl)-acetic acid methyl ester; and
[(lS,3R)-l-(Methoxycarbonylamino-methyl)-3-methyl-cyclopentyl]-acetic acid methyl ester.
More preferred is a process for the preparation of a compound of
formula (4a) wherein R is Ci -Cjo alkyl or C3-C10 cycloalkyl,
Figure imgf000100_0001
comprising, hydrolyzing a compound of formula (3a) , wherein
Figure imgf000100_0002
R\ is H, alkyl, or benzyl.
More preferred is a process for the preparation of a compound of
formula (24a) wherein R is C1 -C1 alkyl or C3-C10
Figure imgf000100_0003
cycloalkyl, comprising, hydrolyzing a compound of formula (23a)
wherein Rj is H, alkyl, or benzyl.
Figure imgf000100_0004
More preferred is a process for the preparation of a compound of
formula (6) wnerein R is CJ-CI Q alkyl or C3-C10 cycloalkyl,
Figure imgf000101_0001
comprising, resolving a
mixture containing compounds of formulas (4a) and (4b)
Figure imgf000101_0002
wherein R is Ci -C J Q alkyl or C3-C1 Q cycloalkyl.
Figure imgf000101_0003
More preferred is a process for the preparation of a compound of
formula (26) wherein R is CI-C I Q alkyl or C3-C1 Q cycloalkyl,
Figure imgf000101_0004
comprising, resolving a
mixture containing compounds of formulas (24a) and
Figure imgf000102_0001
(24b) wherein R is Ci -Ci Q alkyl or C3-C10 cycloalkyl.
Figure imgf000102_0002
More preferred is a process for the preparation of a compound of
Formula I wherein R is CJ -CI Q alkyl or C3-C10 cycloalkyl,
Figure imgf000102_0003
and pharmaceutically acceptable salt thereof, comprising, hydrolyzing a
compound of formula (41) ' wherem Rl is H, alkyl, or
Figure imgf000102_0004
benzyl, and contacting the product, if desired, with an acid or a base.
More preferred is a process for the preparation of a compound of
Formula II wherein R is C J -CJ O alkyl or C3-C10 cycloalkyl,
Figure imgf000102_0005
and pharmaceutically acceptable salt thereof, comprising, hydrolyzing a compound of formula (42) is H,
Figure imgf000103_0001
alkyl, or benzyl, and contacting the product, if desired, with an acid or a base.
More preferred is a process for the preparation of a compound of
Formula III wherein R is Ci -Ci Q alkyl or C3-C10 cycloalkyl,
Figure imgf000103_0002
and pharmaceutically acceptable salt thereof, comprising, hydrolyzing a
compound of formula (43) > wherein Rj is H, alkyl,
Figure imgf000103_0003
or benzyl, and contacting the product, if desired, with an acid or a base.
More preferred is a process for the preparation of a compound of
Formula IV wherein R is Ci -Cj Q alkyl or C3-C1 Q cycloalkyl,
Figure imgf000103_0004
and pharmaceutically acceptable salt thereof, comprising, hydrolyzing a compound of formula (44) is H, alkyl, or
Figure imgf000104_0001
benzyl, and contacting the product, if desired, with an acid or a base.
DETAILED DESCRIPTION OF THE INVENTION
The instant invention is an important process as it permits the synthesis of single isomers; it is a route to stereospecific 3-substituted 5-membered rings of formula
Figure imgf000104_0002
A key feature ofthe invention is the stereoselective preparation of a compound of formula (6) by selective fractional crystallization of a salt of formula (5) from a mixture of compounds of formulas (4a) and (4b), and conversion of a salt of formula (5) to a compound of formula (6). Another feature ofthe invention is the conversion of a compound of formula (2) to a mixture of compounds of formulas (3a) and (3b) wherein the yield of a compound of formula (3 a) over a diastereomer of formula (3 b) may be enhanced by optimizing certain reaction parameters such as, for example, temperature. Reaction of a compound of formula (2) at a relatively low temperature generally provides for a relatively higher yield of a compound of formula (3a) over (3b) than when the reaction is run at a higher temperature. The invention also provides for translation ofthe stereochemistry at the two chiral carbons ofthe cyclopentane ring ofthe resulting pure enantiomer of formula (6) into enantiomerically pure compounds of
Formulas I or II with little or no racemization. Another key feature ofthe invention is the stereoselective preparation of a compound of formula (26) by selective fractional crystallization of salt of formula (25) from a mixture of compounds of formulas (24a) and (24b), and conversion of a salt of formula (25) to a compound of formula (26). Another feature ofthe invention is the conversion of a compound of formula (22) to a mixture of compounds of formulas (23a) and (23b) wherein the yield of a compound of formula (23a) over a diastereomer of formula (23b) may be enhanced by optimizing certain reaction parameters such as, for example, temperature. Reaction of a compound of formula (22) at a relatively low temperature generally provides for a relatively higher yield of a compound of formula (23a) over (23b) than when the reaction is run at a higher temperature. The invention also provides for translation ofthe stereochemistry at the two chiral carbons ofthe cyclopentane ring ofthe resulting pure enantiomer of formula (26) into enantiomerically pure compounds of Formulas III or IV with little or no racemization.
The final products are useful as agents in the treatment of epilepsy, faintness attacks, hypokinesia, cranial disorders, neurodegenerative disorders, depression, anxiety, panic, pain, neuropathological disorders, gastrointestinal disorders such as irritable bowel syndrome (IBS), inflammation especially arthritis, sleep disorders, premenstrual syndrome, and hot flashes.
The following experimental procedures provide a novel route to be used to stereoselectively synthesize 3-substituted cyclopentyl-based analogs of gabapentin and pharmaceutically acceptable salts thereof. These routes provide access to pure stereoisomers of Formulas I, II, III, and IV
Figure imgf000105_0001
wherein R is Ci -Ci Q alkyl or C3-C1 Q cycloalkyl. Examples 1 and 3 below each show a synthesis of a compound of Formula II wherein R is methyl.
Example 2 below shows a synthesis of a compound of Formula I wherein R is methyl. It is understood that compounds of Formulas I, II, III, or IV, or a pharmaceutically acceptable salt thereof, produced by a hydrolysis reaction such as, for example, step j) in the above process for the preparation of a compound of Formula I, or a pharmaceutically acceptable salt thereof, or the process described above wherein a compound of formula (41) is hydrolyzed, may be formed as an acid or base salt thereof, which salt may be optionally converted to a free amino acid form or a pharmaceutically acceptable salt form thereof by methods well known to a skilled person in the pharmaceutical or chemical arts.
The following terms are defined as used herein.
As used herein the term "Cj-Ci Q alkyl" means a straight or branched alkyl group or radical containing from 1 to 10 carbon atoms. Illustrative examples of
CI-CJ O alkyl include methyl, ethyl, 1-propyl, 2-propyl, 1 -butyl, 2-butyl, 2- methyl-1-propyl, 1,1-dimethylethyl, 1-pentyl, 2-pentyl, 3-pentyl, 2,2- dimefhylpropyl, 1-hexyl, 2-hexyl, 3-hexyl, 4-methyl- 1-pentyl, 1-heptyl, 2-heptyl, 3-heptyl, 4-heptyl, 5 -methyl- 1-hexyl, 1-octyl, 2-octyl, 3-octyl, 4-octyl, 6-methyl- 1-heptyl, 5,5-dimethylhexyl, 1-nonyl, 2-nonyl, 1-decyl, and 2-decyl.
The term "C3-C10 cycloalkyl" means a cycloalkyl group or radical having from 3 to 10 carbon atoms. Illustrative examples of a C3-C1 Q cycloalkyl include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl and cyclodecyl. The term "stereoisomer" means any of a group of isomers in which identical atoms are linked in the same order but differ in their spatial arrangement.
* Asterisk symbol points out an enantiomerically enriched chiral carbon atom AcOH Acetic acid
Alkali hydroxide LiOH, NaOH, KOH, or CsOH NH4OAc Ammonium acetate
BnMgCl or PhCH2MgCl Benzylmagnesium chloride t-BuOH or tert-butyl alcohol 1 , 1 -Dimethylethanol teutyl 1,1-Dimethylethyl
CH2C12 Dichloromethane
CC14 Carbon tetrachloride
CDCI3 Deuterochloroform
(CH3)3SiCHN2 Trimethylsilyldiazomethane
CN Carbon-nitrogen triple bond (nitrile)
(COCl)2 Oxalyl chloride
CsOH Cesium hydroxide de Diastereomeric excess
DBU l,8-Diazabicyclo[5.4.0]undec-7-ene
DMF N,N-Dimethylformamide
DMSO Dimefhylsulfoxide
OMSO-d6 Deuterated dimethylsulfoxide ee Enantiomeric excess
Et Ethyl
EtOAc Ethyl acetate
Et3N Triethylamine
HCl Hydrogen chloride
HCl (aq) Hydrochloric acid
6NHC1 6 normal hydrochloric acid
HCl (g) Hydrogen chloride (gaseous)
*H-ΝMR Proton (nuclear) magnetic resonance spectroscopy
IR Infrared spectroscopy
J Coupling constant in Hz
KOH Potassium hydroxide
LCMS Liquid chromatography-mass spectrometry
LiOH Lithium hydroxide Me Methyl
MeO Methoxy
MeCN Acetonitrile
Mel Iodomethane
MeOH Methanol
MgSO4 Magnesium sulfate
MS (ES+) Positive ion electrospray mass spectrometry MS (ES") Negative ion electrospray mass spectrometry MS (CI+) Positive ion chemical ionization mass spectrometry
MS (CL) Negative ion chemical ionization mass spectrometry m/z mass per unit charge NCCH2CO2Et Ethyl cyanoacetate
NaIO4 Sodium periodate
NaOH Sodium hydroxide
ODS Octadecyl-functionalized silica gel
Ph Phenyl
(z-Pr)2NEt Diisopropylethylamine
Rf Rf value
RuCl3 Ruthenium(III) chloride
SOCl2 Thionyl chloride
TFA or CF3CO2H Trifluoroacetic acid
THF Tetrahydrofuran
General Route A
Figure imgf000109_0001
Reagents and Conditions:
(i) NCCH2CO2Et, catalyst (e.g., NH4OAc, ACOH);
(ii) BnMgCl;
(iii) hydrolysis using, for example, alkali hydroxide (e.g., KOH);
(iv) a) resolution using a resolving agent (e.g., (R)- or (S)-α- mefhylbenzylamine); b) conversion ofthe enriched stereoisomer to the free acid using, for example, hydrochloric acid; (v) esterifi cation using, for example, Mel and DBU; (vi) oxidation using, for example, RUCI3 and NaIO4; (vii) (PhO) P(O)N3 and a base (e.g., Et3N);
(viii) MeOH;
(ix) hydrolysis using HCl (aq);
(x) conversion to the free amino acid using, for example, H2O and alkali hydroxide (e.g., NaOH).
General Route B
Figure imgf000111_0001
Figure imgf000111_0003
Figure imgf000111_0002
, (vQ
' HCl
Figure imgf000111_0004
(ix)
Figure imgf000111_0005
Reagents and Conditions:
(i) NCCH2CO2Et, catalyst (e.g., NH4OAc, ACOH);
(ii) BnMgCl;
(iii) hydrolysis using, for example, alkali hydroxide (e.g., KOH); (iv) a) resolution using a resolving agent (e.g., (R)- or (S)-α- methylbenzylamine); b) conversion of salt of enriched stereoisomer to the free acid using, for example, hydrochloric acid; (v) (PhO)2P(O)N3 and base (e.g., Et3N);
(vi) MeOH;
(vii) oxidation using, for example, RUCI3 and NaIO4;
(viii) hydrolysis using HCl (aq);
(ix) conversion to the free amino acid using, for example, H2O and alkali hydroxide (e.g., NaOH).
General Route C
Figure imgf000113_0001
(vi)
Figure imgf000113_0002
(ix)
MeO Z H
Figure imgf000113_0003
(xii)
Figure imgf000113_0004
Reagents and Conditions: (i) NCCH2CO Et, catalyst (e.g., NH4OAc, ACOH);
(ii) BnMgCl;
(iii) hydrolysis using, for example, alkali hydroxide (e.g., KOH); (iv) a) resolution using a resolving agent (e.g., (R)- or (S)-α- methylbenzylamine); b) conversion of salt of enriched stereoisomer to the free acid using, for example, hydrochloric acid; (v) chlorination using, for example, (COCl)2 or SOCI2; (vi) tBuOH and base (e.g., Et3N); (vii) oxidation using, for example, RUCI3 and NaIO4;
(viii) esterification using, for example, (CH3)3SiCHN2 and MeOH; (ix) dealkylation using, for example, CF3CO2H; (x) (PhO)2P(O)N3 and a base (e.g., Et3N);
(xi) MeOH; (xii) hydrolysis using HCl (aq);
(xiii) conversion to the free amino acid using, for example, H2O and alkali hydroxide (e.g., NaOH).
EXAMPLE 1
Figure imgf000115_0001
(ϋ)
Figure imgf000115_0002
(iii)
Figure imgf000115_0003
(iv)
Figure imgf000115_0004
,(vi)
Figure imgf000115_0005
(viii)
Figure imgf000115_0006
(i) NCCH2CO2Et, NH4OAc, AcOH, toluene, reflux;
(ii) PhCH2MgCl, THF, -78°C;
(iii) KOH, ethylene glycol, 160°C;
(iv) (S)-(-)- -methyl benzylamine, EtOAc, 0°C; (v) HCl (aq);
(vi) (PhO)2P(O)N3, Et3N, toluene, reflux;
(vii) MeOH, toluene, reflux;
(viii) RuCl , NaIO4, CCI4, MeCN, H2O;
(ix) 6NHC1, 1,4-dioxane.
(E and Z)-Cyano-((R)-3-methyl-cyclopentylidene)-acetic acid ethyl ester
(R)-(+)-3-Methylcyclopentanone (5 g, 51.0 mmol), ethyl cyanoacetate (5.42 mL, 51.0 mmol), ammonium acetate (0.4 g, 5.1 mmol), and glacial acetic acid (0.58 mL, 10.2 mmol) were refluxed in toluene (30 mL) using a Dean-Stark trap. After 6 hours, the mixture was allowed to cool and diluted with ethyl acetate (100 mL), washed with water (3 x 80 mL), brine, and dried (MgSO4). The solvent was evaporated under reduced pressure. The residue was chromatographed (silica gel, heptane/ethyl acetate, 9:1) to give 8.87 g (90%) of a 1 :1 mixture of (E and Z)- cyano-((R)-3-methyl-cyclopentylidene)-acetic acid ethyl ester; Rf (heptane-ethyl acetate, 9:1) 0.28; IR thin
Figure imgf000116_0001
2225 (CΝ), 1724 (C=O), 1617 (C=C); iH-ΝMR (400 MHz; CDCI3): δ 4.27 (2H, q, J 7.2, CO2CH Me), 4.26 (2H, q,
J7.2, CO2 H2Me), 3.35 (1Η, dt, J7.1, 1.6), 3.30 (1Η, dt, J 7.1, 1.6), 3.23 (1Η, ddd, J8.1, 3.5, 1.7), 3.18 (lΗ, ddd, J8.1, 3.4, 1.7), 3.05-2.67 (4Η, m), 2.50-2.32 (2H, m), 2.29-1.96 (4H, m), 1.50-1.35 (2H, m), 1.34 (3H, t, J7.2, CO2CH2 e), 1.33 (3H, t, J7.1 , CO2CH2M?), 1.10 (3H, d, J 6.6, Me), 1.08 (3H, d, J6.6, Me);
MS (ES"): m/z 192 (M-H, 100%).
(R and S)-((l S.3R)-l-Benzyl-3-methyl-cyclopentyl)-cyano-acetic acid ethyl ester and (R and S)-((lR.3R)-l-Benzyl-3-methyl-cyclopentyl)-cyano-acetic acid ethyl ester A mixture of (E and Z)-cyano-((R)-3-methyl-cyclopentylidene)-acetic acid ethyl ester (4.13 g, 21.4 mmol) in THF (30 mL) was added over 1 hour to a stirring solution of benzylmagnesium chloride (27.7 mL of a 1 M solution in ether, 27.7 mmol) in THF (50 mL) at -78°C under argon. After stirring for a further 1 hour, the mixture was quenched by addition of saturated ammonium chloride solution (15 mL). The mixture was allowed to warm to room temperature, diluted with ether (30 mL), and dilute hydrochloric acid (20 mL) was added. The organic layer was separated, and the aqueous layer was further extracted with ether (2 x 40 mL). The combined ether layers were washed with brine, dried (MgSO4), and the solvent was evaporated under reduced pressure. The residue was chromatographed (silica gel, heptane-ethyl acetate, 95:5) to give 5.8 g (100%) of a 7:7:3:3 mixture of diastereomeric (R and S)-((lS,3R)-l-benzyl-3-methyl- cyclopentyl)-cyano-acetic acid ethyl ester and (R and S)-((lR,3R)-l-benzyl- 3-methyl-cyclopentyl)-cyano-acetic acid ethyl ester; Rf (heptane-ethyl acetate, 9:1) 0.32;
IR thin film (cm"1) 2246 (CN), 1740 (C=O), 1603 (C=C); MS (ES") m/z 284 (M-H, 100%).
((l S.3R)-l-Benzyl-3-methyl-cvclopentyl)-acetic acid and (( 1R,3R)-1 -Benzyl - 3-methyl-cyclopentyl)-acetic acid
The mixture of (R and S)-((lS,3R)-l-benzyl-3-methyl-cyclopentyl)-cyano-acetic acid ethyl ester and (R and S)-((lR,3R)-l-benzyl-3-methyl-cyclopentyl)-cyano- acetic acid ethyl ester (1 g, 3.5 mmol) and potassium hydroxide (1.2 g, 21.4 mmol) were heated to 160°C in ethylene glycol (5 mL) for 16 hours. After this time, the mixture was allowed to cool and dilute hydrochloric acid (150 mL) was added carefully. The mixture was extracted with ethyl acetate (3 x 50 mL), and the combined organic fractions were washed with brine, dried (MgSO4), and the solvent was evaporated under reduced pressure. The residue was chromatographed (silica gel, heptane/ethyl acetate, 98:2) to give 0.65 g (80%) of a 7:3 mixture of ((lS,3R)-l-benzyl-3-methyl-cyclopentyl)-acetic acid and ((1R,3R)- l-benzyl-3-methyl-cyclopentyl)-acetic acid as an oil; Rf (heptane-ethyl acetate, 98:2) 0.36;
IR thin film (cm'l) 1702 (C=O); iH-NMR (400 MHz; CDCI3) major isomer ((l S,3R)-l-benzyl-3-methyl- cyclopentyl)-acetic acid: δ 7.31-7.21 (5H, m, Ph), 2.82 (1H, d, J 13.4, CH^HBCO2H), 2.76 (1H, d, J 13.4, CHAHBC02H), 2.33 (2H, br s, CH2Ph),
2.19-1.66 (m), 1.62-1.52 (m), 1.1 1 (1H, dd, J 13.0, 9.9), 1.01 (3H, d, J 6.6, Me); minor isomer ((lR,3R)-l-benzyl-3-methyl-cyclopentyl)-acetic acid: δ 7.31-7.21 (5H, m, Ph), 2.89 (1H, d, J 13.2, CHAUBC02}ϊ), 2.84 (1H, d, J 13.4, CHAH5CO2H), 2.28 (2H, br s, CH2Ph), 2.19-1.66 (m), 1.62-1.52 (m), 1.30-1.17 (m), 1.00 (3H, d, J6.6, Me);
MS (CL): m/z 231 (M-H, 100%).
((1 S.3R)- 1 -Benzyl-3-methyl-cyclopentyl)-acetic acid
(s)-(-)- -Methyl benzylamine (8.8 g, 72.7 mmol) was added to a stirring solution ofthe diastereomeric mixture of ((lS,3R)-l-benzyl-3-methyl-cyclopentyl)-acetic acid and ((lR,3R)-l-benzyl-3-methyl-cyclopentyl)-acetic acid (16.9 g,
72.7 mmol) dissolved in the minimum quantity of ethyl acetate. The mixture was placed in the fridge and left for 1 hour. After this time, the acid salt had crystallised out and this was filtered off. The salt was recrystallized several times from ethyl acetate (to 95% de). The salt was taken up in ethyl acetate, washed with dilute hydrochloric acid, brine and dried (MgSO4). The solvent was evaporated under reduced pressure to give 6.8 g (40%) of ((lS,3R)-l-benzyl- 3-methyl-cyclopentyl)-acetic acid; LCMS (Prodigy® (Phenomenex, Ltd.) ODS 3 50 mm x 4.6 mm id column, 5-50% Acetonitrile/water) Retention Time = 2.01 min, 98% purity.
((l S.3R)-l-Isocvanatomethyl-3-methyl-cyclopentylmethyl)-benzene
Diphenylphosphoryl azide (4.48 g, 16 mmol), triethylamine (1.69 g, 16.8 mmol), and acid ((lS,3R)-l-benzyl-3-methyl-cyclopentyl)-acetic acid (3.74 g, 16 mmol) were refluxed in toluene (40 mL) for 17 hours. The mixture was allowed to cool and then taken up in ethyl acetate (150 mL), washed with saturated aqueous sodium hydrogen carbonate (200 mL), brine (150 mL), and dried (MgSO4). The solvent was removed under reduced pressure to give 3.69 g (100%) of ((1S,3R)- l-isocyanatomethyl-3-methyl-cyclopentylmethyl)-benzene, which was used without further purification;
Rf (heptane-ethyl acetate, 8:2) 0.36;
IR thin film (cm"1) 2262 (CN).
((lS,3R)-l-Benzyl-3-methyl-cyclopentylmethyl)-carbamic acid methyl ester
((1 S,3R)-1 -Isocyanatomethyl-3-methyl-cyclopentylmethyl)-benzene (3.69 g, 16 mmol) was refluxed in methanol (10 mL) and toluene (20 mL) for 16 hours and then allowed to cool to room temperature. The solvent was removed under reduced pressure, and the residue was purified by chromatography (silica gel, heptane-ethyl acetate 9:1) to give 2.66 g (63%) of ((lS,3R)-l-benzyl-3-methyl- cyclopentylmethyl)-carbamic acid methyl ester; Rf (heptane-ethyl acetate, 8:2) 0.28;
IR thin film (cm"1) 1709 (CO); iH-NMR (400 MHz; CDC13) δ 7.32-7.16 (5H, m, Ph), 4.60 (1H, bs, NH),
3.68 (3H, s, OMe), 3.18-3.00 (2H, m, CH NH), 2.62-2.60 (2H, s, CH2Ph),
0.99 (3Η, d, J6.8, Me), 2.05-1.92, 1.87-1.72, 1.60-1.40, 1.00-0.89 (7H, m); MS (ES+) m/z 262 (M+H, 90%), 302 (M+CH3CN+H,100%);
LCMS (Prodigy® ODS 3 50 mm x 4.6 mm id column, 5-50% Acetonitrile (0.05% formic acid)/water (0.05% formic acid)) Retention Time = 2.1 1, 94% de.
(l S,3R)-l-(Methoxycarbonylamino-methyl)-3-methyl-cvclopentyl]-acetic acid
((lS,3R)-l-Benzyl-3-methyl-cyclopentylmethyl)-carbamic acid methyl ester (2.6 g, 9.9 mmol) and sodium periodate (29.8 g, 140 mmol) were stirred together in carbon tetrachloride (30 mL), acetonitrile (30 mL), and water for 6 hours. The mixture was cooled to 0°C, and rufhenium(lll) chloride (0.04 g, 0.2 mmol) was added to the reaction mixture. The reaction was allowed to warm to room temperature and stirred for 20 hours. Diethyl ether (50 mL) was added, and the mixture was then extracted with saturated aqueous sodium hydrogen carbonate (200 mL). The aqueous layer was acidified to pH 1 with 4N hydrochloric acid and re-extracted with ethyl acetate (200 mL), dried (MgSO4), and the solvent was evaporated under reduced pressure. The residue was purified by chromatography
(silica gel, eluting with a gradient of heptane to 1 :1 heptane: ethyl acetate) to give 0.32 g (14%) of [(l S,3R)-l-(methoxycarbonylamino-methyl)-3-methyl- cyclopentyl] -acetic acid; Rf (heptane-ethyl acetate, 8:2) 0.30; IR thin film (cm"1) 3338 (NH), 1712 (C=O); iH-NMR (400 MHz; CDCI3): δ 9.29 (IH, s, COOH), 5.17 (IH, bs, NH), 3.71 (3H, s, OMe), 3.30 (IH, dd, J 14.4, 7.1, CHAH^N^), 3.17 (1Η, dd, J 14.4, 6.6, CH^ΗBNΗ2), 2.37 (2H, s, CH2COOH), 2.20-1.00 (7H, m), 1.01 (3H, d, J6.4, CH e); MS (ES+) m/z 230 (M+H, 63%), 481 (M+Na,100).
((1 S.3R)-l-Aminomethyl-3-methyl-cyclopentyl)-acetic acid hydrochloride
[(1 S,3R)-1 -(Methoxycarbonylamino-methyl)-3-methyl-cyclopentyl]-acetic acid (0.32 g, 1.4 mmol) was refluxed in a mixture of 1,4-dioxane (3 mL) and 6N Hydrochloric acid (8 mL) for 4 hours. The mixture was allowed to cool, diluted with water (200 mL), and washed with dichloromethane (2 x 200 mL). The aqueous layer was evaporated under reduced pressure, and the residue was recrystallized from ethyl acetate/methanol to give 0.17 g (59%) of ((1S,3R)- 1 -aminomethyl-3 -methyl-cyclopentyl)-acetic acid hydrochloride;
IR thin film (cm"1) 1710 (C=O); iH-NMR (400 MHz; DMSO-ttø): δ 2.96 (IH, d, J 12.8, CH4HBNH ), 2.90 (IH, d, J 12.8, CHAH#NH2), 2.40 (2H, s, CH2COOH), 2.04 (IH, m, CHMe), 1.81-1.61, 1.51-1.43, 1.21-1.11 (5H, m), 1.06 (IH, dd, J 12.8, 10.4), 0.97 (3H, d, J6.35, Me);
MS (ES+) m/z 173 (M+H, 100%), 196 (M+Na, 10%); LCMS (Prodigy® ODS 3 50 mm x 4.6 mm id column, 5% for 2 min, 5-50% over 1.5 min of Acetonitrile (0.05%> formic acidVwater (0.05% formic acid)) Retention Time = 0.92, 94% de.
EXAMPLE 2
Figure imgf000121_0001
(iii)
Figure imgf000121_0002
(i) (CH3)3SiCHN2, MeOH, toluene;
(ii) RuCl3 , NaIO4, CC14, MeCN, H2O;
(iii) (PhO)2P(O)N3, Et N, toluene, reflux;
(iv) MeOH, toluene, reflux;
(v) 6N HC1, 1,4-dioxane.
((l S.3R)-l-Benzyl-3-methyl-cyclopentyl)-acetic acid methyl ester
Trimethylsilyldiazomethane (31.5 mL of a 2 M solution in hexanes, 63 mmol) was added dropwise to a stirring solution of ((lS,3R)-l-benzyl-3-methyl-cyclopentyl)- acetic acid (10 g, 43 mmol) in toluene (80 mL) and methanol (20 mL) at 0°C under argon, and the mixture was allowed to warm to room temperature. The mixture was stirred for 1 hour, and then the solvent was evaporated under reduced pressure. The residue was taken up in ethyl acetate (50 mL), washed with saturated sodium hydrogen carbonate solution, dilute hydrochloric acid, dried (MgSO4), and the solvent removed in vacuo to give 10.6 g (100%) of ((1S,3R)- l-benzyl-3-methyl-cyclopentyl)-acetic acid methyl ester; Rf (heptane-ethyl acetate, 9:1) 0.40;
IR thin film (cm" 1) 1736 (C=O); iH-NMR (400 MHz; CDC13): δ 7.30-7.18 (5H, m, Ph), 3.69 (3H, s, OMe),
2.78 (IH, d, J 13.4, CH4HBCO Me), 2.72 (IH, d, J 13.4, CHAH5CO2Me), 2.28 (2Η, s, CH2Ph), 2.16-1.50 (5H, m), 1.30-1.03 (2H, m), 1.00 (3H, d, J6.6, Me).
((lS.3R)-l-Methoxycarbonylmethyl-3-methyl-cvclopentyl)-acetic acid
((lS,3R)-l-Benzyl-3-methyl-cyclopentyl)-acetic acid methyl ester (10.5 g,
43 mmol) and sodium periodate (128.0 g, 598 mmol) were stirred together in carbon tetrachloride (120 L), acetonitrile (120 mL), and water (210 mL) for 1 hour. The mixture was cooled to 10°C, and ruthenium(III) chloride (0.177 g, 0.86 mmol) was added to the reaction mixture. The reaction was allowed to warm to room temperature and stirred for 20 hours. Diethyl ether (100 mL) was added, and the mixture was acidified to pH 1 with concentrated hydrochloric acid and then extracted with ether (2 x 200 mL). The organic layer was extracted with saturated aqueous sodium hydrogen carbonate (2 x 200 mL) which was then acidified to pH 1 with 4N hydrochloric acid and re-extracted with ethyl acetate, dried (MgSO4), and concentrated in vacuo. The residue was purified by chromatography (silica gel, eluting with a gradient of heptane to 1 :1 heptane:ethyl acetate) to give 8.02 g (87.7%) of ((lS,3R)-l-methoxycarbonylmethyl-3-methyl- cyclopentyl)-acetic acid; Rf (heptane-ethyl acetate, 1 :1) 0.46; IR thin film (cm" 1) 3100 (OH), 1737 (C=O), 1705 (C=O); iH-NMR (400 MHz; CDCI3): δ 3.68 (3H, s, OMe), 2.67-2.51 (4H, m), 2.06 (IH, m), 1.97-1.79 (2H, m), 1.76-1.59 (2H, m), 1.29-1.08 (2H, m), 1.01 (3H, d, J6.6, Me);
MS (ES+) m/z 215 (M+H), 278 (M+Na, 100), 451 (2M+Na, 80%). ((lR,3R -l-Isocvanatomethyl-3-methyl-cyclopentyl)-acetic acid methyl ester
Diphenylphosphoryl azide (8.07 mL, 37.4 mmol), triethylamine (5.36 mL, 39 mmol), and ((lS,3R)-l-methoxycarbonylmethyl-3-methyl-cyclopentyl)-acetic acid (7.93 g, 37 mmol) were refluxed in toluene (80 mL) for 17 hours. The mixture was allowed to cool and then taken up in ethyl acetate (250 mL), washed with saturated aqueous sodium hydrogen carbonate (250 mL), brine (100 mL), and dried (MgSO4). The solvent was removed under reduced pressure to give
7.82 g (100%)) of ((lR,3R)-l-isocyanatomethyl-3-methyl-cyclopentyl)-acetic acid methyl ester which was used without further purification; IR thin film (cm" l ) 2264 (CN), 1732 (C=O).
(lR,3R)-l-(Methoxycarbonylamino-methyl)-3-methyl-cvclopentyll-acetic acid methyl ester
((lR,3R)-l-Isocyanatomethyl-3-methyl-cyclopentyl)-acetic acid methyl ester (7.82 g, 37 mmol) was refluxed in methanol (30 mL) and toluene (80 mL) for 17 hours and then allowed to cool to room temperature. The solvent was removed under reduced pressure, and the residue was purified by chromatography (silica gel, heptane to heptane:ether 8:2) to give 2.60 g (29%) of [(1R,3R)- 1 -(methoxycarbonylamino-methyl)-3-methyl-cyclopentyl]-acetic acid methyl ester; Rf (heptane-ethyl acetate, 1 :1) 0.52;
IR thin film (cm'1) 1728 (CO), 1716 (C=O); iH-NMR (400 MHz; CDC13): δ 3.67 (6H, s, OMe, NHCO2 e), 3.21 (IH, dd, J7.08, 14.2, C/J4HBNHCO2Me), 3.11 (IH, dd, J6.10, 13.9, CHAH/3NHCO2Me), 2.36 (2H, s, CH2CO2Me), 2.05 (1 Η, m, CHMe), 1.86-1.46 & 1.29-1.18 (5Η, m), 0.99 (3H, d, J6.59, Me).
((lR,3R)-l-Aminomethyl-3-methyl-cyclopentyl)-acetic acid hydrochloride
[(lR,3R)-l-(Methoxycarbonylamino-methyl)-3-methyl-cyclopentyl]-acetic acid methyl ester (2.60 g, 37 mmol) was refluxed in a mixture of 1 ,4-dioxane (15 mL) and 6N Hydrochloric acid (30 mL) for 16 hours. The mixture was allowed to cool, diluted with water (80 mL), and washed with dichloromethane (2 x 200 mL). The aqueous layer was evaporated under reduced pressure, and the residue was recrystallized from ethyl acetate/methanol (95:5) to give 0.55 g (25%) of ((lR,3R)-l-aminomethyl-3-methyl-cyclopentyl)-acetic acid hydrochloride;
IR thin film (cm"1) 1724 (C=O); iH-NMR (400 MHz; OMSO-d6): δ 2.92 (IH, d, J 12.9, CH HβN), 2.87 (IH, d, J 12.9, CHAH#N), 2.45 (IH, d, J 15.9, CH^HβCOOH), 2.40 (IH, d, J 15.9, CHA//#COOH), 1.95 (IH, m), 1.84-1.72 (2H, m), 1.60-1.48 (2H, m), 1.20 (IH, m), 1.04 (IH, m), 0.96 (3H, d, J6.8, Me).
EXAMPLE 3
Figure imgf000124_0001
(iii)
Figure imgf000124_0002
(vi)
Figure imgf000124_0003
(i) a) oxalyl chloride, DMF, CH2C12; b) t-BuOH, ( -Pr)2Net, CH2C12;
(ii) RuCl3, NaIO4, CC14, MeCN, H2O;
(iii) (CH3)3SiCHN2, MeOH, toluene;
(iv) CF3CO2H, CH2C12; (v) (PhO)2P(O)N , Et3N, toluene, reflux;
(vi) MeOH, toluene, reflux; (vii) 6NHC1, 1,4-dioxane.
((lS,3R)-l-Benzyl-3-methyl-cyclopentyl)-acetic acid tert-butyl ester
Oxalyl chloride (4.14 mL, 47 mmol) was added dropwise to a stirring solution of ((lS,3R)-l-benzyl-3-methyl-cyclopentyl)-acetic acid (10 g, 43 mmol) in dichloromethane under argon at room temperature. The reaction mixture was cooled to 5°C, dimethylformamide (1 mL) was carefully added, and the mixture was allowed to warm to room temperature and stirred for a further 2 hours. The solvent was removed in vacuo and the residue diluted with dichloromethane (60 mL). 1,1-Dimethylethanol (15 mL) was carefully added to the reaction mixture under argon followed by diisopropylethylamine (11.5 mL, 65 mmol). The mixture was stirred for 17 hours and then taken up in ethyl acetate, washed with saturated aqueous sodium hydrogen carbonate (2 x 200 mL), and dried (MgSO4).
The solvent was removed under reduced pressure, and the residue was purified by chromatography (silica gel, eluting with a gradient of heptane to 9:1 heptane:ethyl acetate) to give 10.92 g (88%) of ((lS,3R)-l-benzyl-3-methyl-cyclopentyl)-acetic acid tert-butyl ester; Rf (heptane-ethyl acetate, 9:1) 0.64;
IR thin film (cm"1) 1724 (C=O); iH-ΝMR (400 MHz;CDCl ): δ 7.29-7.17 (5H, m, Ph), 2.77 (IH, d, J 13.6,
CH HβPh), 2.71 (IH, d, J 13.6, CHAH^Ph), 2.18 (IH, s, CH4HBCO tButyl),
2.17 (IH, s,CHAH5CO2tButyl) , 1.49 (9Η, s, CMe3), 2.17-1.5 & 1.30-1.00 (7H, m), 1.00 (3H, d, J6.8, CH e).
[(l S.3R)-l-Carboxymethyl-3-methyl-cvclopentyl]-acetic acid tert-butyl ester ((lS,3R)-l-Benzyl-3-methyl-cyclopentyl)-acetic acid tert-butyl ester (10.72 g, 37.2 mmol) and sodium periodate (124.77 g, 0.583 mol) were stirred together in carbon tetrachloride (120 mL), acetonitrile (120 mL), and water (210 mL) for 2 hours. The mixture was cooled to 0°C, and ruthenium(III) chloride (0.173 g, 0.83 mmol) was added to the reaction mixture. The reaction was allowed to warm to room temperature and stirred for 48 hours. Diethyl ether (60 mL) was added, and the mixture was then acidified to pH 2 by the addition of dilute hydrochloric acid. The mixture was extracted with ethyl acetate (2 x 200 mL), dried (MgSO4), and concentrated in vacuo. The residue was purified by chromatography (silica gel, eluting with a gradient of heptane to 1 :1 heptane:ethyl acetate) to give 7.01 g
(73.5%) of [(lS,3R)-l-carboxymethyl-3-methyl-cyclopentyl]-acetic acid tert-butyl ester; Rf (heptane-ethyl acetate, 1 :1) 0.58;
IR thin film (cm"1) 2953 (OH), 1726 (C=O) 1705 (C=O); 1H-NMR (400 MHz; CDC13): δ 2.51 (2H, s, CH CO), 2.46 (2H, s, CH2CO),
1.47 (9H, s, CMe3), 2.05-2.15, 1.95-1.80, 1.75-1.60, 1.30-1.03 (7H, m), 1.01 (3H, d, J6.4, Me).
[(lS.3R)-l-Methoxycarbonylmethyl-3-methyl-cvclopentyl"|-acetic acid tert-butyl ester
Trimethylsilyldiazomethane (14 mL of a 2 M solution in hexanes, 26.9 mmol) was added dropwise to a stirring solution of [(lS,3R)-l-carboxymethyl-3-methyl- cyclopentyl] -acetic acid tert-butyl ester (6.9 g, 26.9 mmol) in toluene (60 mL) and methanol (15 mL) at 10°C under argon, and the mixture was allowed to warm to room temperature. The mixture was stirred for 2 hours, and then the solvent was evaporated under reduced pressure. The residue was taken up in ethyl acetate
(200 mL), washed with saturated sodium hydrogen carbonate solution, dilute hydrochloric acid, dried (MgSO4), and the solvent removed in vacuo. The residue was purified by chromatography (silica gel, eluting with a gradient of heptane to 95:5 heptane:ethyl acetate) to give 6.73 g (92.4%) of [(1S.3R)- l-methoxycarbonylmethyl-3-methyl-cyclopentyl]-acetic acid tert-butyl ester; Rf (heptane-ethyl acetate, 9:1) 0.36;
IR thin film (cm"1) 1738 (CO) 1732 (CO); iH-NMR (400 MHz; CDC13): δ 3.65 (3H, s, OMe), 2.52 (2H, m, CH2CO2), 2.45 (IH, d, J4.8, CH CO2), 1.44 (9H, s, CMe3), 2.05-1.5, 1.30-1.10 (7H, m), 1.00 (3H, d, J6.8, Me).
((lR,3R)-l-Methoxycarbonylmethyl-3-methyl-cvclopentyl)-acetic acid
[(1 S,3R)- 1 -Methoxycarbonylmethyl-3-methyl-cyclopentyl]-acetic acid tert-butyl ester (6.64 g, 24.6 mmol) and trifluoroacetic acid (10 mL) were stirred together in dichloromethane (30 mL) for 17 hours at room temperature. The mixture was carefully poured into aqueous sodium carbonate and extracted with ethyl acetate
(200 mL). The aqueous was acidified to pH 1 with concentrated hydrochloric acid and re-extracted with ethyl acetate (3 x 200 mL), dried (MgSO4), and concentrated in vacuo. The residue was purified by chromatography (silica gel, eluting with a gradient of heptane to 1 :1 heptane: ethyl acetate) to give 5.26 g (100%) of [(lR,3R)-l-methoxycarbonylmethyl-3-methyl-cyclopentyl]-acetic acid;
Rf (heptane-ethyl acetate, 1 :1) 0.46;
IR thin film (cm"1) 2952 (OH), 1737 (CO), 1706(CO); iH-NMR (400 MHz; CDCI3): δ 3.68 (3H, s, OMe), 2.67 (IH, d, J 15.0, CH4HBCO2), 2.61 (IH, d, J 14.9, CHAHβCO2), 2.58 (IH, d, J 14.8, CH4HBCO2), 2.53 (IH, d, J 14.8, CHAH^CO2), 1.93-1.81, 1.75-1.59,
1.75-1.63 (6H, m), 1.16 (IH, dd, J 19.5, 9.3), 1.01 (3H, d, J6.35, Me).
((lS.3R)-l-Isocyanatomethyl-3-methyl-cvclopentyl)-acetic acid methyl ester
Diphenylphosphoryl azide (5.35 mL, 24.8 mmol), triethylamine (3.55 mL, 25.6 mmol), and [(l R,3R)-l-methoxycarbonylmethyl-3-methyl-cyclopentyl]- acetic acid (5.26 g, 24.5 mmol) were refluxed in toluene (80 mL) for 17 hours.
The mixture was allowed to cool and then taken up in ethyl acetate (300 mL), washed with saturated aqueous sodium hydrogen carbonate solution (250 mL), brine (200 mL), and dried (MgSO4). The solvent was removed under reduced pressure to give 5.19 g (100%) of ((lS,3R)-l-isocyanatomethyl-3-methyl- cyclopentyl)-acetic acid methyl ester which was used without further purification;
IR thin film (cm"1) 2262 (NCO), 1732 (CO).
[(lS,3R)-l-(Methoxycarbonylamino-methyl)-3-methyl-cvclopentyll-acetic acid methyl ester
((lS,3R)-l-Isocyanatomethyl-3-methyl-cyclopentyl)-acetic acid methyl ester (5.19 g, 24.5 mmol) was refluxed in methanol (30 mL) and toluene (80 mL) for 17 hours and then allowed to cool to room temperature. The solvent was removed under reduced pressure, and the residue was purified by chromatography (silica gel, heptane-ethyl acetate 9:1) to give 4.62 g (77%) of [(1S,3R)-1-
(methoxycarbonylamino-methyl)-3-methyl-cyclopentyl]-acetic acid methyl ester; Rf (heptane-ethyl acetate, 1 :1) 0.59;
IR thin film (cm"1) 1730 (CO); iH-NMR (400 MHz; CDC13): δ 3.68 (6H, s, OMe, NHCO e), 3.27 (IH, dd, J 13.7, 6.8, CH4HBNHCO2Me), 3.13 (IH, dd, J 13.9, 6.4, CHAHβNHCO2Me),
2.37 (IH, d, J 13.9, CH4HBCO2), 2.33 (IH, d, J 13.9, CHAH#CO2), 2.09-1.99 (1Η, m, CHMe), 1.88-1.76, 1.69-1.43, 1.28-1.19 (6Η, m), 1.01 (3H, d, J6.4, Me); m/z (CI+) 244 (M+H, 100%).
((1 S, 3 R)-l- Aminomethyl-3 -methyl-cyclopentyD-acetic acid hydrochloride
[(1 S,3R)-1 -(Methoxycarbonylamino-methyl)-3-methyl-cyclopentyl]-acetic acid methyl ester (2.84 g, 1 1.7 mmol) was refluxed in a mixture of 1,4-dioxane (15 mL) and 6N Hydrochloric acid (30 mL) for 17 hours. The mixture was allowed to cool, diluted with water (200 mL), and washed with dichloromethane (2 x 100 mL). The aqueous layer was evaporated under reduced pressure, and the residue was recrystallized from ethyl acetate/methanol (95:5) to give 1.28 g (53%) of ((lS,3R)-l-aminomethyl-3-methyl-cyclopentyl)-acetic acid hydrochloride;
IR thin film (cm"1) 1710 (CO); *H-NMR (400 MHz; OMSO-d6): δ 2.96 (IH, d, J 12.8, CH4HBNH2), 2.90 (IH, d, J 12.8, CHAHβNH2), 2.40 (2H, s, CH COOH), 2.09-1.98 (IH, m, CHMe),
1.81-1.61 , 1.51-1.43, 1.21-1.1 1(5H, m), 1.04 (IH, dd, J 13.2, 10.4), 0.97 (3H, d, J6.35, Me);
MS (ES+) m/z 173 (M+H, 100%), 196 (M+Na, 10%);
LCMS (Prodigy® ODS 3 50 mm x 4.6 mm id column, 5% for 2 min, 5-50% over
1.5 min of acetonitrile (0.05% formic acid)/water (0.05% formic acid)) Retention
Time = 0.92, 94% de; (Found: C, 49.5; H, 8.78; N, 6.37.
C9H17NO2 1HC1 0.6H2O requires C, 49.5; H, 8.86; N, 6.41).

Claims

1. A process for the preparation of a compound of Formula I
Figure imgf000130_0001
R wherein R is Cj-Cio alkyl or C3-C10 cycloalkyl, and pharmaceutically acceptable salts thereof, which comprises: a) adding a cyanoacetate of formula (A)
Figure imgf000130_0002
, wherein Ri is alkyl or benzyl, to a mixture of a chiral cyclopentanone of
formula (1) , a solvent, a carboxylic acid, and a
Figure imgf000130_0003
R
Knoevenagel reaction catalyst, and stirring the mixture in the presence of a means of removing water to produce the alkene of
formula (2)
Figure imgf000130_0004
R b) adding the product of Step a) above to a mixture of benzylmagnesium chloride, benzylmagnesium bromide, or benzylmagnesium iodide, in a solvent to produce the addition products of formulas (3a) and (3b)
Figure imgf000131_0001
R
Figure imgf000131_0002
R adding the products of Step b) above to a mixture of a base selected from potassium hydroxide, sodium hydroxide, lithium hydroxide, or cesium hydroxide in a solvent and stirring, and then acidifying to
produce the carboxylic acids of formulas (4a)
Figure imgf000131_0003
R
Figure imgf000131_0004
R adding the products of Step b) above to an acid mixture and stirring
to produce the carboxylic acids of formulas (4a)
Figure imgf000131_0005
Figure imgf000131_0006
R d) contacting the products of Step c) above with an amine in a solvent, and recrystallizing the salt so formed to produce the enriched
diastereomer of formula (5) as the amine
Figure imgf000132_0001
salt; e) converting the product of Step d) to a carboxylic acid of formula (6)
Figure imgf000132_0002
f) adding the product of Step e) to a mixture of iodomethane, a solvent, and a base, and stirring to produce the ester of formula (7)
or adding the product of Step e) to methanol
Figure imgf000132_0003
and an acid to produce the ester of formula (7)
Figure imgf000132_0004
R or adding the product of Step e) above to trimethylsilyldiazomethane and methanol in a solvent to produce the ester of
formula (7)
Figure imgf000132_0005
R or adding the product of Step e) to a solution of diazomethane or trimethylsilyl-diazomethane in a solvent to produce ester of
formula (7)
Figure imgf000133_0001
R g) adding the product of Step f) to a mixture of carbon tetrachloride or ethyl acetate, and acetonitrile, water, sodium periodate, and ruthenium(III) chloride, and stirring to produce the carboxylic acid of
formula (8)
Figure imgf000133_0002
R h) adding the product of Step g) to a mixture of a tertiary amine base, a solvent, and diphenylphosphoryl azide (DPP A), and stirring to
produce the isocyanate of formula (9) or
Figure imgf000133_0003
R adding the product of Step g) above to ethyl chloroformate or isobutyl chloroformate and a base in a solvent at a temperature of from -40°C to 78°C, followed by adding a solution of sodium azide in water and tetrahydrofuran or acetone, followed by adding toluene or benzene, and refluxing to produce the isocyanate of formula (9)
Figure imgf000133_0004
i) adding the product of Step h) to a mixture of a solvent and methanol, and stirring to produce the carbamate of formula (10)
Figure imgf000134_0001
j) adding the product of Step i) to a mixture of a solvent and aqueous hydrochloric acid, and stirring to produce a compound of
formula (la) ; and
Figure imgf000134_0002
R k) converting the product of Step j) to a compound of formula (I)
, and further converting, if desired, to a
Figure imgf000134_0003
pharmaceutically acceptable salt by known means.
A process according to Claim 1 which comprises: a) adding a cyanoacetate of formula (A) NC^^ υ2 1 wherein R\ is selected from methyl, ethyl, «-propyl, zso-propyl, «-butyl, wo-butyl, sec-butyl, tert-butyl, and benzyl to a mixture of a chiral
cyclopentanone of formula (1) a solvent selected from
Figure imgf000134_0004
tetrahydrofuran, 1 ,4-dioxane, tert-butylmethylether, chloroform, dichloromethane, acetonitrile, ethyl ether, ethyl acetate, hexanes, N,N-dimethylformamide, dimethylsulfoxide, ethanol, tert-butanol, toluene, benzene, xylenes, and rø-heptane, acetic acid, and a Knoevenagel reaction catalyst selected from β-alanine, ammonium acetate, and piperidine, and stirring the mixture in the presence of a means of removing water selected from azeotropic distillation, activated molecular sieves, anhydrous magnesium sulfate, anhydrous sodium sulfate, anhydrous sodium carbonate, anhydrous potassium carbonate, anhydrous cesium carbonate, trimethyl orthoformate, and triethyl orthoformate to produce the alkene of formula (2)
Figure imgf000135_0001
R b) adding the product of Step a) above to a mixture of benzylmagnesium chloride, benzylmagnesium bromide, or benzylmagnesium iodide in a solvent selected from tetrahydrofuran, benzene, 1 ,4-dioxane, hexanes, M-heptane, toluene, diethyl ether, and tert-butyl methyl ether to produce the addition products of
formulas (3a) and , ( ,3„,b ,)
Figure imgf000135_0002
Figure imgf000135_0003
R R c) adding the products of Step b) above to a mixture of a base selected from potassium hydroxide, sodium hydroxide, lithium hydroxide, and cesium hydroxide in a solvent selected from ethylene glycol, 2-methoxyethyl ether, 1 ,4-dioxane, and diethylene glycol, and stirring the mixture, and then acidifying to produce the carboxylic acids of formulas (4a) and (4b)
Figure imgf000136_0001
R
Figure imgf000136_0002
R adding the products of Step b) above to an acid mixture selected from 6-12 M HCl, 12 M H2SO4, 10%-48% wt/wt hydrobromic acid, and HBr in aqueous acetic acid, and stirring to produce the
carboxylic acids of formulas (4a) and (4b)
R
Figure imgf000136_0004
R contacting the products of Step c) above with an amine selected from (S)-α-methyl-benzylamine, (R)-α-methyl-benzylamine, (R)-(+)-l- (naphthyl)ethylamine, (S)-(+)- 1 -(naphthyl)ethylamine, triethylamine, diisopropylethylamine, dicyclohexylamine, benzylamine, dibenzylamine, morpholine, N-methylmorpholine, piperidine, N-methylpiperidine, and pyridine in a solvent selected from N,N- dimethylformamide, chloroform, benzene, xylenes, hexanes, acetone, ethanol, methanol, zso-propanol, diethyl ether, dichloromethane, benzene, toluene, n-pentane, n-hexane, n-heptane, ethyl acetate, acetonitrile, tert-butyl methyl ether, tetrahydrofuran, and 1,4-dioxane, and recrystallizing the salt so formed to produce the
enriched diastereomer of formula (5) s the
Figure imgf000137_0001
amine salt; e) adding the product of Step d) to a mixture selected from aqueous hydrochloric acid, aqueous sulfuric acid, aqueous acetic acid, hydrochloric acid dissolved in acetic acid, or hydrochloric acid dissolved in acetic acid to which water is added and stirring to
produce the carboxylic acid of formula (6) ; or
Figure imgf000137_0002
partitioning the product of Step d) between a mixture of aqueous hydrochloric acid and a solvent selected from chloroform, dichloromethane, ethyl acetate, ethyl ether, tetrahydrofuran, 1 ,4-dioxane, toluene, and tert-butylmethylether, and drying and evaporating the organic layer to produce the carboxylic acid of
formula (6) ;
Figure imgf000137_0003
f) adding the product of Step e) above to a mixture of iodomethane, a solvent selected from dichloromethane, chloroform, tetrahydrofuran, toluene, and 1,4-dioxane, and a base selected from 1,8- diazabicyclo[5.4.0]undec-7-ene (DBU), diisopropylethylamine, triethylamine, and l ,5-diazabicyclo[4.3.0]non-5-ene (DBN), and stirring at a temperature of from -40°C to 110°C to produce the ester of formula (1) , ' or adding the product of Step e)
Figure imgf000138_0001
R above to a mixture of methanol and concentrated sulphuric acid, concentrated hydrochloric acid, or hydrogen chloride at a temperature of from 0°C to 100°C to produce the ester of formula (7)
ove to
Figure imgf000138_0002
R trimethylsilyldiazomethane and methanol in benzene or toluene at a temperature of from -40°C to 100°C to produce the ester of
formula (7) • or adding the product of Step e)
Figure imgf000138_0003
above to diazomethane or trimethylsilyldiazomethane in a solvent selected from benzene, toluene, dichloromethane, and diethyl ether at a temperature of from -40°C to 40°C to give a compound of
formula (7) ;
Figure imgf000138_0004
R adding the product of Step f) to a mixture of carbon tetrachloride or ethyl acetate, and acetonitrile, water, sodium periodate, and ruthenium(III) chloride, and stirring at a temperature from -40°C to 80°C to produce the carboxylic acid of formula (8)
Figure imgf000139_0001
R h) adding the product of Step g) above to a mixture of a base selected from triethylamine and diisopropylethylamine, a solvent selected from toluene, benzene, xylenes, tetrahydrofuran, diethyl ether and 77-heptane, and diphenylphosphoryl azide (DPP A), and stirring at a temperature of from 0°C to 150°C to produce the isocyanate of
formula (9) or adding the product of Step g)
Figure imgf000139_0002
R above to ethyl chloroformate or isobutyl chloroformate, a base selected from triethylamine and diisopropylethylamine, and a solvent selected from tetrahydrofuran, acetone, and diethyl ether at a temperature of from -40°C to 78°C, followed by adding a solution of sodium azide in water and tetrahydrofuran or acetone, followed by adding toluene or benzene, and refluxing to produce the isocyanate
of formula (9)
Figure imgf000139_0003
R i) adding the product of Step h) to a mixture of a solvent selected from toluene, benzene, xylenes and «-heptane, and methanol, and stirring at a temperature from 0°C to 150°C to produce the carbamate of
formula (10)
Figure imgf000140_0001
R j) adding the product of Step i) to a mixture of a solvent selected from water, acetic acid, and 1 ,4-dioxane, and aqueous hydrochloric acid at a concentration of from 0.01 M to 12 M, and stirring at a temperature from 0°C to 115°C to produce a compound of formula la
Figure imgf000140_0002
R k) converting the product of Step j) to a compound of Formula I
, and further converting, if desired, to a
Figure imgf000140_0003
pharmaceutically acceptable salt by known means.
A process according to Claim 1 which comprises: a) adding a cyanoacetate of formula (A) NC^^^ 1 , wherein R is ethyl, to a mixture of a chiral cyclopentanone of formula (1)
Figure imgf000140_0004
R which is ammonium acetate, and heating the mixture at reflux over a Dean-Stark trap to produce the alkene of formula (2)
Figure imgf000141_0001
R b) adding the product of Step a) above to a mixture of benzylmagnesium chloride in dry tetrahydrofuran at -100°C to 25°C
to produce the addition products of formulas (3 a)
Figure imgf000141_0002
R
Figure imgf000141_0003
R c) adding the products of Step b) above to a mixture of potassium hydroxide in ethylene glycol, and heating the mixture at 100°C to 200°C, and then acidifying to produce the hydrolysis products of
formulas (4a)
Figure imgf000141_0004
d) contacting the products of Step c) above with (S)-α-methyl- benzylamine in ethyl acetate, and recrystallizing the salt so formed from ethyl acetate to produce the enriched diastereomer of formula (5) as the (S)-α-methyl-
Figure imgf000142_0001
benzylamine salt; e) adding the product of Step d) to aqueous hydrochloric acid and
stirring to produce the carboxylic acid of formula (6)
Figure imgf000142_0002
f) adding the product of Step e) to a mixture of iodomethane, dichloromethane, and l,8-diazabicyclo[5.4.0]undec-7-ene (DBU),
and stirring to produce the ester of formula (7)
Figure imgf000142_0003
or adding the product of Step e) to methanol and concentrated
sulfuric acid to produce the ester of formula (7)
Figure imgf000142_0004
R ' or adding the product of Step e) to a solution of diazomethane or trimethylsilyl-diazomethane in dichloromethane to produce the ester
of formula (7)
Figure imgf000142_0005
g) adding the product of Step f) to a mixture of carbon tetrachloride or ethyl acetate, and acetonitrile, water, sodium periodate, and ruthenium(III) chloride, and stirring to produce the carboxylic acid of
formula (8)
Figure imgf000143_0001
R h) adding the product of Step g) to a mixture of triethylamine, toluene, and diphenylphosphoryl azide (DPP A), and refluxing to produce the
isocyanate of formula (9)
Figure imgf000143_0002
product of Step g) above to ethyl chloroformate or isobutyl chloroformate and triethylamine in tetrahydrofuran at a temperature of from -40°C to 78°C, followed by adding a solution of sodium azide in water and tetrahydrofuran, followed by adding toluene or benzene, and refluxing to produce ester of formula (9)
Figure imgf000143_0003
R i) adding the product of Step h) to a mixture of methanol and toluene, and refluxing to produce the carbamate of formula (10)
Figure imgf000143_0004
j) adding the product of Step i) to a mixture of 1 ,4-dioxane and aqueous hydrochloric acid at a concentration of 6 M, and stirring to produce a
compound of formula la
Figure imgf000144_0001
R k) converting the product of Step j) to a compound of Formula I
NW2 , and further converting, if desired, to a
Figure imgf000144_0002
R pharmaceutically acceptable salt by known means.
4. A process according to Claim 1 , further characterized in that the
intermediate product (9) formed is reacted, without
Figure imgf000144_0003
R isolation, with methanol to produce the carbamate of formula (10)
Figure imgf000144_0004
R
5. A process for the preparation of a compound of Formula II
Figure imgf000145_0001
wherein R is Ci -CJ O alkyl or C3-C1 o cycloalkyl, and pharmaceutically acceptable salts thereof, which comprises: a) adding a cyanoacetate of formula (A) NC^ C02R1 , wherein R4 is alkyl or benzyl, to a mixture of a chiral cyclopentanone of
formula (1) a solvent, a carboxylic acid, and a
Figure imgf000145_0002
R
Knoevenagel reaction catalyst, and stirring the mixture in the presence of a means of removing water to produce the alkene of
formula (2)
Figure imgf000145_0003
R b) adding the product of Step a) above to a mixture of benzylmagnesium chloride, benzylmagnesium bromide, or benzylmagnesium iodide, in a solvent to produce the addition
products of formulas (3a) and (3b)
Figure imgf000146_0001
R
Figure imgf000146_0002
R adding the products of Step b) above to a mixture of a base selected from potassium hydroxide, sodium hydroxide, lithium hydroxide, and cesium hydroxide and a solvent, and stirring, and then acidifying
to produce the carboxylic acids of formulas (4a)
Figure imgf000146_0003
Figure imgf000146_0004
adding the products of Step b) above to an acid mixture and stirring
to produce the carboxylic acids of formulas (4a)
Figure imgf000146_0005
Figure imgf000146_0006
R d) contacting the products of Step c) above with an amine in a solvent, and recrystallizing the salt so formed to produce the enriched
diastereomer of formula (5) as the amine
Figure imgf000147_0001
salt; and e) converting the product of Step d) to a carboxylic acid of formula (6)
Figure imgf000147_0002
f) adding the product of Step e) to a mixture of a tertiary amine base, a solvent, and diphenylphosphoryl azide (DPP A), and stirring to
produce the isocyanate of formula (1 1) ; or adding
Figure imgf000147_0003
R the product of Step e) above to ethyl chloroformate or isobutyl chloroformate and a base in a solvent at a temperature of from -40°C to 78°C, followed by adding a solution of sodium azide in water and tetrahydrofuran or acetone, followed by adding toluene or benzene,
and refluxing to produce isocyanate of formula (11)
Figure imgf000147_0004
g) adding the product of Step f) to a mixture of a solvent and methanol, and stirring to produce the carbamate of formula (12)
Figure imgf000148_0001
R h) adding the product of Step g) to a mixture of carbon tetrachloride or ethyl acetate, and acetonitrile, water, sodium periodate, and rufhenium(III) chloride, and stirring to produce the carboxylic acid of
formula (13)
Figure imgf000148_0002
R i) adding the product of Step h) to a mixture of a solvent and aqueous hydrochloric acid, and stirring to produce a compound of
formula (Ila) -HCl .
Figure imgf000148_0003
R j) converting the product of Step i) to a compound of formula (II)
, and further converting, if desired, to a
Figure imgf000148_0004
R pharmaceutically acceptable salt by known means.
6. A process according to Claim 5 which comprises: a) adding a cyanoacetate of formula (A) NC^^/-*-^1^! wherein R\ is selected from methyl, ethyl, «-propyl, w -propyl, rø-butyl, wo-butyl, sec-butyl, tert-butyl, and benzyl to a mixture of a chiral
cyclopentanone of formula (1) , a solvent selected from
Figure imgf000149_0001
R tetrahydrofuran, 1 ,4-dioxane, tert-butylmethylether, chloroform, dichloromethane, acetonitrile, ethyl ether, ethyl acetate, hexanes, N,N-dimethylformamide, dimethylsulfoxide, ethanol, tert-butanol, toluene, benzene, xylenes, and rø-heptane, acetic acid, and a Knoevenagel reaction catalyst selected from β-alanine, ammonium acetate, and piperidine, and stirring the mixture in the presence of a means of removing water selected from azeotropic distillation, activated molecular sieves, anhydrous magnesium sulfate, anhydrous sodium sulfate, anhydrous sodium carbonate, anhydrous potassium carbonate, anhydrous cesium carbonate, trimethyl orthoformate, and triethyl orthoformate to produce the alkene of formula (2)
Figure imgf000149_0002
R b) adding the product of Step a) above to a mixture of benzylmagnesium chloride, benzylmagnesium bromide, or benzylmagnesium iodide in a solvent selected from tetrahydrofuran, benzene, 1,4-dioxane, hexanes, ^-heptane, toluene, diethyl ether, and tert-butyl methyl ether to produce the addition products of
formulas (3 a) and (3b)
Figure imgf000150_0001
Figure imgf000150_0002
R R adding the products of Step b) above to a mixture of a base selected from potassium hydroxide, sodium hydroxide, lithium hydroxide, and cesium hydroxide in a solvent selected from ethylene glycol, 2-methoxyethyl ether, 1,4-dioxane, and diethylene glycol, and stirring the mixture and then acidifying to produce the carboxylic
acids of formulas (4a) (4b)
Figure imgf000150_0003
R
Figure imgf000150_0004
R adding the products of Step b) above to an acid mixture selected from 6-12 M HCl, 12 M H2SO , 10%-48% wt/wt hydrobromic acid, and HBr in aqueous acetic acid, and stirring to produce the
carboxylic acids of formulas (4a) and (4b)
Figure imgf000151_0001
R
Figure imgf000151_0002
R d) contacting the products of Step c) above with an amine selected from (S)-α-methyl-benzylamine, (R)-α-methyl-benzylamine, (R)-(+)-l- (naphthyl)ethylamine, (S)-(+)- 1 -(naphthyl)ethylamine, triethylamine, diisopropylethylamine, dicyclohexylamine, benzylamine, dibenzylamine, morpholine, N-methylmorpholine, piperidine, N-methylpiperidine, and pyridine in a solvent selected from N,N- dimefhylformamide, chloroform, benzene, xylenes, hexanes, acetone, ethanol, methanol, wo-propanol, diethyl ether, dichloromethane, benzene, toluene, n-pentane, n-hexane, n-heptane, ethyl acetate, acetonitrile, tert-butyl methyl ether, tetrahydrofuran, and 1 ,4-dioxane, and recrystallizing the salt so formed to produce the
enriched diastereomer of formula (5) the
Figure imgf000151_0003
amine salt; e) adding the product of Step d) to a mixture selected from aqueous hydrochloric acid, aqueous sulfuric acid, aqueous acetic acid, hydrochloric acid dissolved in acetic acid, and hydrochloric acid dissolved in acetic acid and water, and stirring to produce the
carboxylic acid of formula (6) ; or
Figure imgf000152_0001
partitioning the product of Step d) between a mixture of aqueous hydrochloric acid and a solvent selected from chloroform, dichloromethane, ethyl acetate, ethyl ether, tetrahydrofuran,
1,4-dioxane, toluene, and tert-butylmethylether, and drying and evaporating the organic layer to produce the carboxylic acid of
formula (6) ;
Figure imgf000152_0002
adding the product of Step e) above to a mixture of a base selected from triethylamine and diisopropylethylamine, a solvent selected from toluene, benzene, xylenes, tetrahydrofuran, diethyl ether and «-heptane, and diphenylphosphoryl azide (DPP A), and stirring at a temperature of from 0°C to 150°C to produce the isocyanate of
formula (11) or adding the product of Step e) above
Figure imgf000152_0003
R to ethyl chloroformate or isobutyl chloroformate and a base selected from triethylamine and diisopropylethylamine, and a solvent selected from tetrahydrofuran, acetone, and diethyl ether at a temperature of from -40°C to 78°C, followed by adding a solution of sodium azide in water and tetrahydrofuran or acetone, followed by adding toluene or benzene, and refluxing to produce the isocyanate of formula (1 1)
Figure imgf000153_0001
R g) adding the product of Step f) to a solvent selected from toluene, benzene, xylenes, and ^-heptane, and methanol, and stirring at a temperature from 0°C to 150°C to produce the carbamate of
formula (12)
Figure imgf000153_0002
R h) adding the product of Step g) to a mixture of carbon tetrachloride or ethyl acetate, and acetonitrile, water, sodium periodate, and ruthenium(III) chloride, and stirring at a temperature from -40°C to 80°C to produce the carboxylic acid of formula (13)
Figure imgf000153_0003
R i) adding the product of Step h) to a mixture of a solvent selected from water, acetic acid, and 1 ,4-dioxane, and aqueous hydrochloric acid at a concentration of from 0.01 M to 12 M, and stirring at a temperature from 0°C to 1 15°C to produce a compound of formula Ila
Figure imgf000153_0004
R j) converting the product of Step i) to a compound of Formula II
and further converting, if desired, to a
Figure imgf000154_0001
R pharmaceutically acceptable salt by known means.
A process according to Claim 5 which comprises: a) adding a cyanoacetate of formula (A) NC ^/-(-u2 1 , wherein R is ethyl, to a mixture of a chiral cyclopentanone of formula (1)
Figure imgf000154_0002
which is ammonium acetate, and heating the mixture at reflux over a Dean-Stark trap to produce the alkene of formula (2)
Figure imgf000154_0003
R b) adding the product of Step a) above to a mixture of benzylmagnesium chloride in dry tetrahydrofuran at -100°C to 25°C
to produce the addition products of formulas (3 a)
Figure imgf000155_0001
Figure imgf000155_0002
R c) adding the products of Step b) above to a mixture of potassium hydroxide in ethylene glycol, and heating the mixture at 100°C to 200°C, and then acidifying to produce the hydrolysis products of
formulas (4a) and (4b)
Figure imgf000155_0003
Figure imgf000155_0004
R R d) contacting the products of Step c) above with (S)-α-methyl- benzylamine in ethyl acetate, and recrystallizing the salt so formed from ethyl acetate to produce the enriched diastereomer of
formula (5) as the (S)-α-mefhyl-
Figure imgf000155_0005
benzylamine salt; e) adding the product of Step d) to aqueous hydrochloric acid and
stirring to produce the carboxylic acid of formula (6)
Figure imgf000155_0006
f) adding the product of Step e) to a mixture of triethylamine, toluene, and diphenylphosphoryl azide (DPP A), and refluxing to produce the
isocyanate of formula (1 1) or adding the product
Figure imgf000156_0001
R of Step e) above to ethyl chloroformate or isobutyl chloroformate and triethylamine in tetrahydrofuran at a temperature of from -40°C to 78°C, followed by adding a solution of sodium azide in water and tetrahydrofuran or acetone, followed by adding toluene or benzene,
and refluxing to produce isocyanate of formula (11)
Figure imgf000156_0002
g) adding the product of Step f) to a mixture of methanol and toluene, and refluxing to produce the carbamate of formula (12)
Figure imgf000156_0003
h) adding the product of Step g) to a mixture of carbon tetrachloride or ethyl acetate, and acetonitrile, water, sodium periodate, and ruthenium(III) chloride, and stirring to produce the carboxylic acid of
formula (13)
Figure imgf000156_0004
R i) adding the product of Step h) to a mixture of 1 ,4-dioxane and aqueous hydrochloric acid at a concentration of 6 M, and stirring to
produce a compound of formula Ila
Figure imgf000157_0001
R j) converting the product of Step i) to a compound of Formula II
5 ancι further converting, if desired, to a
Figure imgf000157_0002
R pharmaceutically acceptable salt by known means.
8. A process according to Claim 5, further characterized in that the
intermediate product (11) formed is further reacted,
Figure imgf000157_0003
R without isolation, with methanol to produce the carbamate of formula (12)
Figure imgf000157_0004
9. A process for the preparation of a compound of Formula II
Figure imgf000158_0001
R wherein R is Ci -Cι g alkyl or C3-C10 cycloalkyl, and pharmaceutically acceptable salts thereof, which comprises: a) adding a cyanoacetate of formula (A) NC ^/*-'υ2 1 , wherein R\ is alkyl or benzyl, to a mixture of a chiral cyclopentanone of
formula (1) a solvent, a carboxylic acid, and a
Figure imgf000158_0002
R
Knoevenagel reaction catalyst, and stirring the mixture in the presence of a means of removing water to produce the alkene of
formula (2)
Figure imgf000158_0003
R b) adding the product of Step a) above to a mixture of benzylmagnesium chloride, benzylmagnesium bromide, or benzylmagnesium iodide, in a solvent to produce the addition
products of formulas (3a) and (3b)
Figure imgf000159_0001
R
Figure imgf000159_0002
R adding the products of Step b) above to a mixture of a base selected from potassium hydroxide, sodium hydroxide, lithium hydroxide, and cesium hydroxide, in a solvent, and stirring, and then acidifying
to produce the carboxylic acids of formulas (4a)
Figure imgf000159_0003
Figure imgf000159_0004
R adding the products of Step b) above to an acid mixture and stirring
to produce the carboxylic acids of formulas (4a)
Figure imgf000159_0005
R
Figure imgf000159_0006
d) contacting the products of Step c) above with an amine in a solvent, and recrystallizing the salt so formed to produce the enriched
diastereomer of formula (5) as the amine
Figure imgf000160_0001
salt; e) converting the product of Step d) to a carboxylic acid of formula (6)
Figure imgf000160_0002
f) adding oxalyl chloride to a mixture ofthe product of Step e), a solvent, and N,N-dimethylformamide (DMF), and stirring to produce
the acid chloride of formula (14)
Figure imgf000160_0003
g) adding the product of Step f) to a mixture of tert-butyl alcohol, a solvent, and a tertiary amine base, and stirring to produce the ester of
formula (15)
Figure imgf000160_0004
h) adding the product of Step g) to a mixture of carbon tetrachloride or ethyl acetate, and acetonitrile, water, sodium periodate, and ruthenium(III) chloride, and stirring to produce the carboxylic acid of
formula (16)
Figure imgf000161_0001
R i) adding the product of Step h) to a mixture of a solvent, methanol, and (trimethylsilyl)diazomethane, and stirring to produce the bis ester of
formula ( 17) . or adding the product of Step h)
Figure imgf000161_0002
R to a mixture of iodomethane, a solvent, and a base, and stirring to
produce the bis ester of formula (17)
Figure imgf000161_0003
R j) adding an acid to a mixture ofthe product from Step i) and a solvent, and stirring to produce the carboxylic acid of formula (18)
Figure imgf000161_0004
k) adding the product of Step j) to a mixture of a tertiary amine base, a solvent, and diphenylphosphoryl azide (DPP A) is added, and stirring to produce the isocyanate of formula (19) ; or
Figure imgf000162_0001
R adding the product of Step j) above to ethyl chloroformate or isobutyl chloroformate and a base in a solvent at a temperature of from -40°C to 78°C, followed by adding a solution of sodium azide in water and tetrahydrofuran or acetone, followed by adding toluene or benzene,
and refluxing to produce isocyanate of formula (19)
Figure imgf000162_0002
R
1) adding the product of Step k) to a mixture of a solvent and methanol, and stirring to produce the carbamate of formula (20)
Figure imgf000162_0003
R m) adding the product of Step 1) to a mixture of a solvent and aqueous hydrochloric acid is added, and stirring to produce a compound of
formula (Ila) HCl and
Figure imgf000162_0004
R n) converting the product of Step m) to a compound of formula (II)
, and further converting, if desired, to a
Figure imgf000163_0001
R pharmaceutically acceptable salt by known means.
10. A process according to Claim 9 which comprises': a) adding a cyanoacetate of formula (A) NC-^ C02R1 wherein Rj is selected from methyl, ethyl, rø-propyl, tsø-propyl, «-butyl, wo-butyl, sec-butyl, tert-butyl, and benzyl to a mixture of a chiral
cyclopentanone of formula (1) , a solvent selected from
Figure imgf000163_0002
R tetrahydrofuran, 1 ,4-dioxane, tert-butylmethylether, chloroform, dichloromethane, acetonitrile, ethyl ether, ethyl acetate, hexanes, N,N-dimethylformamide, dimethylsulfoxide, ethanol, tert-butanol, toluene, benzene, xylenes, and «-heptane, acetic acid, and a Knoevenagel reaction catalyst selected from β-alanine, ammonium acetate, and piperidine, and stirring the mixture in the presence of a means of removing water selected from azeotropic distillation, activated molecular sieves, anhydrous magnesium sulfate, anhydrous sodium sulfate, anhydrous sodium carbonate, anhydrous potassium carbonate, anhydrous cesium carbonate, trimethyl orthoformate, and triethyl orthoformate to produce the alkene of formula (2)
Figure imgf000163_0003
R b) adding the product of Step a) above to a mixture of benzylmagnesium chloride, benzylmagnesium bromide, or benzylmagnesium iodide in a solvent selected from tetrahydrofuran, benzene, 1 ,4-dioxane, hexanes, «-heptane, toluene, diethyl ether, and tert-butyl methyl ether to produce the addition products of
formulas (3 a) and (3b)
Figure imgf000164_0002
Figure imgf000164_0001
R R c) adding the products of Step b) above to a mixture of a base selected from potassium hydroxide, sodium hydroxide, lithium hydroxide, and cesium hydroxide in a solvent selected from ethylene glycol, 2-methoxyefhyl ether, 1,4-dioxane, and diethylene glycol, and stirring the mixture and then acidifying to produce the carboxylic
acids of formulas (4a) and (4b)
Figure imgf000164_0003
Figure imgf000164_0004
R adding the products of Step b) above to an acid mixture selected from 6-12 M HCl, 12 M H2SO4, 10%-48% wt/wt hydrobromic acid, and HBr in aqueous acetic acid, and stirring to produce the carboxylic acids and (4b)
Figure imgf000165_0001
R
Figure imgf000165_0002
R d) contacting the products of Step c) above with an amine selected from (S)-α-methyl-benzylamine, (R)-α-mefhyl-benzylamine, (R)-(+)-l- (naphfhyl)efhylamine, (S)-(+)-l-(naphthyl)ethylamine, triethylamine, diisopropylethylamine, dicyclohexylamine, benzylamine, dibenzylamine, morpholine, N-methylmorpholine, piperidine, N-methylpiperidine, and pyridine in a solvent selected from N,N- dimethylformamide, chloroform, benzene, xylenes, hexanes, acetone, ethanol, methanol, z o-propanol, diethyl ether, dichloromethane, benzene, toluene, n-pentane, n-hexane, n-heptane, ethyl acetate, acetonitrile, tert-butyl methyl ether, tetrahydrofuran, and 1,4-dioxane, and recrystallizing the salt so formed to produce the
enriched diastereomer of formula (5) as the
Figure imgf000165_0003
amine salt; e) adding the product of Step d) to a mixture selected from aqueous hydrochloric acid, aqueous sulfuric acid, aqueous acetic acid, hydrochloric acid dissolved in acetic acid, or hydrochloric acid dissolved in acetic acid and water, and stirring to produce the
carboxylic acid of formula (6) ; or
Figure imgf000166_0001
partitioning the product of Step d) between a mixture of aqueous hydrochloric acid and a solvent selected from chloroform, dichloromethane, ethyl acetate, ethyl ether, tetrahydrofuran,
1 ,4-dioxane, toluene, and tert-butylmethylether, and drying and evaporating the organic layer to produce the carboxylic acid of
formula (6) ;
Figure imgf000166_0002
f) adding oxalyl chloride to a mixture ofthe product of Step e), a solvent selected from dichloromethane, chloroform, ethyl ether, toluene, and tert-butyl methyl ether, and 0.01 to 10 mole percent of N,N-dimethylformamide (DMF), and stirring at a temperature from -40°C to 110°C to produce the acid chloride of formula (14)
Figure imgf000166_0003
g) adding the product of Step f) to a mixture of tert-butyl alcohol, a solvent selected from dichloromethane, chloroform, ethyl ether, toluene, and tert-butyl methyl ether, and NN-diisopropylethylamine (DIPEA) or triethylamine, and stirring at a temperature from -40°C
to 110°C to produce the ester of formula (15)
Figure imgf000167_0001
R h) adding the product of Step g) to a mixture of carbon tetrachloride or ethyl acetate, and acetonitrile, water, sodium periodate, and ruthenium(III) chloride, and stirring at a temperature from -40°C to 80°C to produce the carboxylic acid of formula (16)
Figure imgf000167_0002
R i) adding the product of Step h) to a solvent selected from toluene, benzene, xylenes, and «-heptane, methanol, and (trimethylsilyl)diazomethane, and stirring at a temperature from 0°C to 150°C to produce the bis ester of formula (17)
. or addιng the product of Step h) to a mixture
Figure imgf000167_0003
R of iodomethane, a solvent selected from dichloromethane, chloroform, tetrahydrofuran, toluene and 1 ,4-dioxane, and a base selected from l,8-diazabicyclo[5.4.0]undec-7-ene (DBU), diisopropylethylamine, triethylamine, or l,5-diazabicyclo[4.3.0]non- 5-ene (DBN), and stirring at a temperature of from -40°C to 110°C to
produce the bis ester of formula (17)
Figure imgf000168_0001
R j) adding hydrochloric acid or trifluoroacetic acid (TFA) to a mixture ofthe product from Step i) and a solvent selected from dichloromethane, chloroform, 1 ,4-dioxane, tetrahydrofuran, ethyl ether, and tert-butyl methyl ether, and stirring at a temperature from -40°C to 110°C to produce the carboxylic acid of formula (18)
Figure imgf000168_0002
R k) adding the product of Step j) to a mixture of a base selected from triethylamine and diisopropylethylamine, a solvent selected from toluene, benzene, xylenes, and ^-heptane, and diphenylphosphoryl azide (DPP A), and stirring at a temperature from 0°C to 150°C to
produce the isocyanate of formula (19) ; or adding
Figure imgf000168_0003
R the product of Step j) above to ethyl chloroformate or isobutyl chloroformate, a base selected from triethylamine and diisopropylethylamine, and a solvent selected from tetrahydrofuran, acetone, and diethyl ether at a temperature of from -40°C to 78°C, followed by adding a solution of sodium azide in water and tetrahydrofuran or acetone, followed by adding toluene or benzene,
and refluxing to produce isocyanate of formula (19)
Figure imgf000169_0001
R
1) adding the product of Step k) to a mixture of a solvent selected from toluene, benzene, xylenes, and «-heptane, and methanol, and stirring at a temperature from 0°C to 150°C to produce the carbamate of
formula (20)
Figure imgf000169_0002
R m) adding the product of Step 1) to a mixture of a solvent selected from water, acetic acid, and 1 ,4-dioxane, and aqueous hydrochloric acid at a concentration of from 0.01 M to 12 M, and stirring at a temperature from 0°C to 115°C to produce a compound of formula Ila
Figure imgf000169_0003
R n) converting the product of Step m) to a compound of Formula II
; and further converting, if desired, to a
Figure imgf000169_0004
R pharmaceutically acceptable salt by known means.
1. A process according to Claim 9 which comprises: a) adding a cyanoacetate of formula (A) NC^ υ2 1 , wherein R is ethyl, to a mixture of a chiral cyclopentanone of formula (1)
toluene, acetic acid, and a Knoevenagel reaction catalyst
Figure imgf000170_0001
R which is ammonium acetate, and heating the mixture at reflux over a Dean-Stark trap to produce the alkene of formula (2)
Figure imgf000170_0002
R b) adding the product of Step a) above to a mixture of benzylmagnesium chloride in dry tetrahydrofuran at -100°C to 25°C
to produce the addition products of formulas (3a)
Figure imgf000170_0003
Figure imgf000170_0004
R c) adding the products of Step b) above to a mixture of potassium hydroxide in ethylene glycol and heating the mixture at 100°C to 200°C, and then acidifying to produce the hydrolysis products of
formulas (4a)
Figure imgf000171_0001
d) contacting the products of Step c) above with (S)- -methyl- benzylamine in ethyl acetate, and recrystallizing the salt so formed from ethyl acetate to produce the enriched diastereomer of
formula (5) as the (S)-α-methyl-
Figure imgf000171_0002
benzylamine salt; e) adding the product of Step d) to aqueous hydrochloric acid and
stirring to produce the carboxylic acid of formula (6)
Figure imgf000171_0003
f) adding oxalyl chloride to a mixture of the product of Step e), dichloromethane, and a catalytic amount of N,N-dimethylformamide (DMF), and stirring to produce the acid chloride of formula (14)
Figure imgf000171_0004
g) adding the product of Step f) to a mixture of tert-butyl alcohol, dichloromethane, and NN-diisopropylethylamine (DIPEA), and
stirring to produce the ester of formula (15)
Figure imgf000172_0001
h) adding the product of Step g) to a mixture of carbon tetrachloride or ethyl acetate, and acetonitrile, water, sodium periodate, and ruthenium(III) chloride, and stirring to produce the carboxylic acid of
formula (16)
Figure imgf000172_0002
i) adding the product of Step h) to a mixture of methanol, toluene, and (trimethylsilyl)diazomethane, and stirring to produce the bis ester of
formula (17) CO2t-Bu . or adding the product of Step h)
Figure imgf000172_0003
R to a mixture of iodomethane, dichloromethane, triethylamine, and stirring to produce the bis ester of formula (17)
Figure imgf000172_0004
R j) adding hydrochloric acid or trifluoroacetic acid (TFA) to a mixture ofthe product from Step i) and dichloromethane, and stirring to
produce the carboxylic acid of formula (18) .
Figure imgf000173_0001
R k) adding the product of Step j) to a mixture of triethylamine, toluene, and diphenylphosphoryl azide (DPP A), and refluxing to produce the
isocyanate of formula (19) or adding the product of
Figure imgf000173_0002
R
Step j) above to ethyl chloroformate or isobutyl chloroformate, triethylamine, and tetrahydrofuran at a temperature of from -40°C to 78°C, followed by adding a solution of sodium azide in water and tetrahydrofuran or acetone, followed by adding toluene or benzene,
and refluxing to produce isocyanate of formula (19)
Figure imgf000173_0003
R
1) adding the product of Step k) to a mixture of methanol and toluene, and refluxing to produce the carbamate of formula (20)
Figure imgf000173_0004
R m) adding the product of Step 1) to a mixture of 1 ,4-dioxane and aqueous hydrochloric acid at a concentration of 6 M, and stirring to produce a
compound of formula Ila 'HC1
Figure imgf000174_0001
R n) converting the product of Step m) to a compound of Formula II
} and further converting, if desired, to a
Figure imgf000174_0002
R pharmaceutically acceptable salt by known means.
12. A process according to Claim 9, further characterized in that the
intermediate product (14) formed is further reacted, without
Figure imgf000174_0003
isolation, with tert-butyl alcohol to produce the ester of formula (15)
13. A process according to Claim 9, characterized in that the intermediate
product (19) formed is further reacted, without isolation,
Figure imgf000175_0001
R with methanol to produce the carbamate of formula (20)
Figure imgf000175_0002
R
14. A process according to Claim 9, characterized in that the intermediate
product (14) is further reacted, without isolation,
Figure imgf000175_0003
with tert-butyl alcohol to produce the ester of formula (15)
, and the intermediate product ( 19)
Figure imgf000175_0005
Figure imgf000175_0004
R R formed is further reacted, without isolation, with methanol to produce the
carbamate of formula (20)
Figure imgf000175_0006
R
15. A process for the preparation of a compound of Formula III
Figure imgf000176_0001
wherein R is Ci -Ci Q alkyl or C3-C1 Q cycloalkyl, and pharmaceutically acceptable salts thereof, which comprises: a) adding a cyanoacetate of formula (A) NC^/^2 1 , wherein R\ is alkyl or benzyl, to a mixture of a chiral cyclopentanone of
formula (21) a solvent, a carboxylic acid, and a
Figure imgf000176_0002
Knoevenagel reaction catalyst, and stirring the mixture in the presence of a means of removing water to produce the alkene of
formula (22)
Figure imgf000176_0003
b) adding the product of Step a) above to a mixture of benzylmagnesium chloride or benzylmagnesium iodide, in a solvent to produce the addition of products of formulas (23 a)
Figure imgf000176_0004
c) adding the products of Step b) above to a mixture of a base selected from potassium hydroxide, sodium hydroxide, lithium hydroxide, and cesium hydroxide, in a solvent, and stirring, and then acidifying to produce the carboxylic acids of formulas (24a)
Figure imgf000177_0001
Figure imgf000177_0002
adding the products of Step b) above to an acid mixture, and stirring
to produce the carboxylic acids of formulas (24a)
Figure imgf000177_0003
Figure imgf000177_0004
contacting the products of Step c) above with an amine in a solvent, and recrystallizing the salt so formed to produce the enriched
diastereomer of formula (25) as the amine
Figure imgf000177_0005
salt; and e) converting the product of Step d) to a carboxylic acid of formula (26)
Figure imgf000178_0001
f) adding the product of Step e) to a mixture of iodomethane, a solvent, and l,8-diazabicyclo[5.4.0]undec-7-ene (DBU), and stirring to
produce the ester of formula (27)
Figure imgf000178_0002
product of Step e) to methanol and an acid to produce the ester of
formula (27) product of Step e) to
Figure imgf000178_0003
a solution of diazomethane or trimethylsilyl-diazomethane in a
solvent to produce ester of formula (27)
Figure imgf000178_0004
g) adding the product of Step f) to a mixture of carbon tetrachloride or ethyl acetate, and acetonitrile, water, sodium periodate, and rufhenium(III) chloride, and stirring to produce the carboxylic acid of
formula (28)
Figure imgf000178_0005
h) adding the product of Step g) to a mixture of a tertiary amine base, a solvent, and diphenylphosphoryl azide (DPP A), and stirring to
produce the isocyanate of formula (29) or
Figure imgf000179_0001
adding the product of Step g) above to ethyl chloroformate or isobutyl chloroformate and a base in a solvent at a temperature of from -40°C to 78°C, followed by adding a solution of sodium azide in water and tetrahydrofuran or acetone, followed by adding toluene or benzene, and refluxing to produce isocyanate of formula (29)
Figure imgf000179_0002
i) adding the product of Step h) to a mixture of a solvent and methanol, and stirring to produce the carbamate of formula (30)
Figure imgf000179_0003
j) adding the product of Step i) to a mixture of a solvent and aqueous hydrochloric acid, and stirring to produce a compound of
formula (Ilia) ;
Figure imgf000179_0004
k) converting the product of Step j) to a compound of formula (III) , and further converting, if desired, to a
Figure imgf000180_0001
pharmaceutically acceptable salt by known means.
16. A process for the preparation of a compound of Formula IV
Figure imgf000180_0002
wherein R is Cj-Cio alkyl or C3-C10 cycloalkyl, and pharmaceutically acceptable salts thereof, which comprises: a) adding a cyanoacetate of formula (A) NC^1-^ 1 , wherein R\ is alkyl or benzyl, to a mixture of a chiral cyclopentanone of
formula (21) a solvent, a carboxylic acid, and a
Figure imgf000180_0003
Knoevenagel reaction catalyst, and stirring the mixture in the presence of a means of removing water to produce the alkene of
formula (22)
Figure imgf000180_0004
b) adding the product of Step a) above to a mixture of benzylmagnesium chloride or benzylmagnesium iodide, in a solvent to produce the addition of products of formulas (23a)
Figure imgf000181_0001
c) adding the products of Step b) above to a mixture of a base selected from potassium hydroxide, sodium hydroxide, lithium hydroxide, and cesium hydroxide, in a solvent, and stirring, and then acidifying
to produce the carboxylic acids of formulas (24a)
Figure imgf000181_0002
Figure imgf000181_0003
adding the products of Step b) above to an acid mixture, and stirring
to produce the carboxylic acids of formulas (24a)
Figure imgf000181_0004
Figure imgf000181_0005
d) contacting the products of Step c) above with an amine in a solvent, and recrystallizing the salt so formed to produce the enriched diastereomer of formula (25) as the amine
Figure imgf000182_0001
salt; and e) converting the product of Step d) to a carboxylic acid of formula (26)
Figure imgf000182_0002
f) adding the product of Step e) to a mixture of a tertiary amine base, a solvent, and diphenylphosphoryl azide (DPP A) is added, and stirring
to produce the isocyanate of formula (31 ) or
Figure imgf000182_0003
adding the product of Step g) above to ethyl chloroformate or isobutyl chloroformate and a base in a solvent at a temperature of from -40°C to 78°C, followed by adding a solution of sodium azide in water and tetrahydrofuran or acetone, followed by adding toluene or benzene, and refluxing to produce the isocyanate of formula (31)
Figure imgf000182_0004
g) adding the product of Step f) to a mixture of a solvent and methanol, and stirring to produce the carbamate of formula (32)
Figure imgf000183_0001
h) adding the product of Step g) to a mixture of carbon tetrachloride or ethyl acetate, and acetonitrile, water, sodium periodate, and ruthenium(III) chloride, and stirring to produce the carboxylic acid of
formula (33)
Figure imgf000183_0002
i) adding the product of Step h) to a mixture of a solvent and aqueous hydrochloric acid, and stirring to produce a compound of
formula (IVa) -HCl and
Figure imgf000183_0003
j) converting the product of Step i) to a compound of formula (IV)
, and further converting, if desired, to a
Figure imgf000183_0004
pharmaceutically acceptable salt by known means.
17. A process for the preparation of a compound of Formula IV
Figure imgf000184_0001
wherein R is Ci -Ci Q alkyl or C3-C10 cycloalkyl, and pharmaceutically acceptable salts thereof, which comprises: a) adding a cyanoacetate of formula (A) M C02R1 , wherein Rj is alkyl or benzyl, to a mixture of a chiral cyclopentanone of
formula (21) , a solvent, a carboxylic acid, and a
Figure imgf000184_0002
Knoevenagel reaction catalyst, and stirring the mixture in the presence of a means of removing water to produce the alkene of
formula (22)
Figure imgf000184_0003
b) adding the product of Step a) above to a mixture of benzylmagnesium chloride or benzylmagnesium iodide, in a solvent to produce the addition of products of formulas (23a)
Figure imgf000184_0004
c) adding the products of Step b) above to a mixture of a base selected from potassium hydroxide, sodium hydroxide, lithium hydroxide, and cesium hydroxide, in a solvent, and stirring, and then acidifying to produce the carboxylic acids of formulas (24a)
Figure imgf000185_0001
Figure imgf000185_0002
adding the products of Step b) above to an acid mixture, and stirring
to produce the carboxylic acids of formulas (24a)
Figure imgf000185_0003
Figure imgf000185_0004
contacting the products of Step c) above with an amine in a solvent, and recrystallizing the salt so formed to produce the enriched
diastereomer of formula (25) as the amine
Figure imgf000185_0005
salt; and e) converting the product of Step d) to a carboxylic acid of formula (26)
Figure imgf000186_0001
f) adding oxalyl chloride to a mixture ofthe product of Step e), a solvent, and N,N-dimethylformamide (DMF), and stirring to produce
the acid chloride of formula (34)
Figure imgf000186_0002
g) adding the product of Step f) to a mixture of tert-butyl alcohol, a solvent, and a tertiary amine base, and stirring to produce the ester of
formula (35)
Figure imgf000186_0003
h) adding the product of Step g) to a mixture of carbon tetrachloride or ethyl acetate, and acetonitrile, water, sodium periodate, and rufhenium(III) chloride, and stirring to produce the carboxylic acid of
formula (36)
Figure imgf000186_0004
i) adding the product of Step h) to a mixture of a solvent, methanol, and (trimethylsilyl)diazomethane, and stirring to produce the bis ester of formula (37) ; or adding the product of Step h)
Figure imgf000187_0001
to a mixture of iodomethane, a solvent, and a base, and stirring to
produce the bis ester of formula (37)
Figure imgf000187_0002
j) adding an acid to a mixture ofthe product from Step i) and a solvent and stirring to produce the carboxylic acid of formula (38)
Figure imgf000187_0003
k) adding the product of Step j) to a mixture of a tertiary amine base, a solvent, and diphenylphosphoryl azide (DPP A), and stirring to
produce the isocyanate of formula (39) ; or adding
Figure imgf000187_0004
the product of Step j) above to ethyl chloroformate or isobutyl chloroformate and a base in a solvent at a temperature of from -40°C to 78°C, followed by adding a solution of sodium azide in water and tetrahydrofuran or acetone, followed by adding toluene or benzene,
and refluxing to produce isocyanate of formula (39)
Figure imgf000188_0001
1) adding the product of Step k) to a mixture of a solvent and methanol, and stirring to produce the carbamate of formula (40)
Figure imgf000188_0002
m) adding the product of Step 1) to a mixture of a solvent and hydrochloric acid, and stirring to produce a compound of
formula (IVa) HC1
Figure imgf000188_0003
n) converting the product of Step m) to a compound of Formula IV
and further converting, if desired, to a
Figure imgf000188_0004
pharmaceutically acceptable salt by known means.
18. A process for the preparation of a compound of formula (6) Q alkyl or C3-C 1 Q cycloalkyl, and
Figure imgf000189_0001
pharmaceutically acceptable salts thereof, which comprises: a) adding a cyanoacetate of formula (A) NC.^ U2 1 , wherein R\ is alkyl or benzyl, to a mixture of a chiral cyclopentanone of
formula (1) , a solvent, a carboxylic acid, and a
Figure imgf000189_0002
R
Knoevenagel reaction catalyst, and stirring the mixture in the presence of a means of removing water to produce the alkene of
Figure imgf000189_0003
R b) adding the product of Step a) above to a mixture of benzylmagnesium chloride, benzylmagnesium bromide, or benzylmagnesium iodide, in a solvent to produce the addition
products of formulas (3 a) and (3b)
Figure imgf000189_0004
R
Figure imgf000189_0005
R c) adding the products of Step b) above to a mixture of a base selected from potassium hydroxide, sodium hydroxide, lithium hydroxide, and cesium hydroxide, and a solvent, and stirring, and then acidifying to produce the carboxylic acids of formulas (4a)
Figure imgf000190_0001
adding the products of Step b) above to an acid mixture and stirring
to produce the carboxylic acids of formulas (4a)
Figure imgf000190_0002
Figure imgf000190_0003
R d) contacting the products of Step c) above with an amine in a solvent, and recrystallizing the salt so formed to produce the enriched
diastereomer of formula (5) s the amine
Figure imgf000190_0004
salt; and e) converting the product of Step d) to a carboxylic acid of formula (6)
Figure imgf000190_0005
9. A process according to Claim 18 which comprises: a) adding a cyanoacetate of formula (A) NC^/^υ2 1 wherein Ri is selected from methyl, ethyl, «-propyl, wo-propyl, «-butyl, iso-butyl, sec-butyl, tert-butyl, and benzyl to a mixture of a chiral
cyclopentanone of formula (1) , a solvent selected from
Figure imgf000191_0001
tetrahydrofuran, 1 ,4-dioxane, tert-butylmethylether, chloroform, dichloromethane, acetonitrile, ethyl ether, ethyl acetate, hexanes, N,N-dimethylformamide, dimefhylsulfoxide, ethanol, tert-butanol, toluene, benzene, xylenes, and rø-heptane, acetic acid, and a Knoevenagel reaction catalyst selected from β-alanine, ammonium acetate, and piperidine, and stirring the mixture in the presence of a means of removing water selected from azeotropic distillation, activated molecular sieves, anhydrous magnesium sulfate, anhydrous sodium sulfate, anhydrous sodium carbonate, anhydrous potassium carbonate, anhydrous cesium carbonate, trimethyl orthoformate, and triethyl orthoformate to produce the alkene of formula (2)
Figure imgf000191_0002
R b) adding the product of Step a) above to a mixture of benzylmagnesium chloride, benzylmagnesium bromide, or benzylmagnesium iodide in a solvent selected from tetrahydrofuran, benzene, 1 ,4-dioxane, hexanes, π-heptane, toluene, diethyl ether, and tert-butyl methyl ether to produce the addition products of
formulas (3 a) and (3b)
Figure imgf000192_0001
R
Figure imgf000192_0002
adding the products of Step b) above to a mixture of a base selected from potassium hydroxide, sodium hydroxide, lithium hydroxide, and cesium hydroxide in a solvent selected from ethylene glycol, 2-methoxyethyl ether, 1 ,4-dioxane, and diethylene glycol, and stirring the mixture, and then acidifying to produce the carboxylic
acids of formulas (4a)
Figure imgf000192_0003
R
; or adding the products of Step b) above to an
Figure imgf000192_0004
R acid mixture selected from 6-12 M HCl, 12 M H SO4, 10%-48% wt/wt hydrobromic acid, and HBr in aqueous acetic acid, and stirring
to produce the carboxylic acids of formulas (4a)
Figure imgf000192_0005
R
Figure imgf000192_0006
d) contacting the products of Step c) above with an amine selected from (S)-α-methyl-benzylamine, (R)-α-mefhyl-benzylamine, (R)-(+)-l- (naphthyl)ethylamine, (S)-(+)-l -(naphthyl)ethylamine, triethylamine, diisopropylethylamine, dicyclohexylamine, benzylamine, dibenzylamine, morpholine, N-mefhylmorpholine, piperidine,
N-methylpiperidine, and pyridine in a solvent selected from N,N- dimethylformamide, chloroform, benzene, xylenes, hexanes, acetone, ethanol, methanol, z'so-propanol, diethyl ether, dichloromethane, benzene, toluene, n-pentane, n-hexane, n-heptane, ethyl acetate, acetonitrile, tert-butyl methyl ether, tetrahydrofuran, and
1,4-dioxane, and recrystallizing the salt so formed to produce the
enriched diastereomer of formula (5) as the
Figure imgf000193_0001
amine salt; and e) adding the product of Step d) to a mixture selected from aqueous hydrochloric acid, aqueous sulfuric acid, aqueous acetic acid, hydrochloric acid dissolved in acetic acid, and hydrochloric acid dissolved in acetic acid and water, and stirring to produce the
carboxylic acid of formula (6) ; or
Figure imgf000193_0002
partitioning the product of Step d) between a mixture of aqueous hydrochloric acid and a solvent selected from chloroform, dichloromethane, ethyl acetate, ethyl ether, tetrahydrofuran, 1,4-dioxane, toluene, and tert-butylmethylether, and drying and evaporating the organic layer to produce the carboxylic acid of
formula (6)
Figure imgf000194_0001
20. A process according to Claim 18 which comprises: a) adding a cyanoacetate of formula (A) NC /LU 2 j ^ wherem R^ is ethyl, to a mixture of a chiral cyclopentanone of formula (1)
Figure imgf000194_0002
R which is ammonium acetate, and heating the mixture at reflux over a Dean-Stark trap to produce the alkene of formula (2)
Figure imgf000194_0003
R b) adding the product of Step a) above to a mixture of benzylmagnesium chloride in dry tetrahydrofuran at -100°C to 25°C
to produce the addition products of formulas (3 a)
Figure imgf000194_0004
R
Figure imgf000194_0005
R c) adding the products of Step b) above to a mixture of potassium hydroxide in ethylene glycol, and heating the mixture at 100°C to 200°C, and then acidifying to produce the hydrolysis products of
formulas (4a)
Figure imgf000195_0001
R R ά) contacting the products of Step c) above with (S)-α-methyl- benzylamine in ethyl acetate, and recrystallizing the salt so formed from ethyl acetate to produce the enriched diastereomer of
formula (5) as the
Figure imgf000195_0002
(S)- -methyl-benzylamine salt; e) adding the product of Step d) to aqueous hydrochloric acid and
stirring to produce the carboxylic acid of formula (6)
Figure imgf000195_0003
21. A process for the preparation of a compound of formula (26)
wherein R is C 1 -C j Q alkyl or C 1 -C 1 Q cycloalkyl, and
Figure imgf000195_0004
pharmaceutically acceptable salts thereof, which comprises: a) adding a cyanoacetate of formula (A) N(- 2 1 , wherein R\ is alkyl or benzyl, to a mixture of a chiral cyclopentanone of formula (21) a solvent, a carboxylic acid, and a
Figure imgf000196_0001
Knoevenagel reaction catalyst, and stirring the mixture in the presence of a means of removing water to produce the alkene of
formula (22)
Figure imgf000196_0002
b) adding the product of Step a) above to a mixture of benzylmagnesium chloride or benzylmagnesium iodide, in a solvent to produce the addition of products of formulas (23a)
Figure imgf000196_0003
c) adding the products of Step b) above to a mixture of a base selected from potassium hydroxide, sodium hydroxide, lithium hydroxide, and cesium hydroxide, and a solvent, and stirring, and then acidifying to produce the carboxylic acids of formulas (24a)
Figure imgf000196_0004
adding the products of Step b) above to an acid mixture, and stirring
to produce the carboxylic acids of formulas (24a)
Figure imgf000197_0001
Figure imgf000197_0002
d) contacting the products of Step c) above with an amine in a solvent, and recrystallizing the salt so formed to produce the enriched
Figure imgf000197_0003
salt; and e) converting the product of Step d) to a carboxylic acid of formula (26)
Figure imgf000197_0004
22. A process according to Claim 21 which comprises: a) adding a cyanoacetate of formula (A) NC^/1^ 1 , wherein R] is selected from methyl, ethyl, «-propyl, t o-propyl, «-butyl, z'so-butyl, sec-butyl, tert-butyl, and benzyl, to a mixture of a chiral cyclopentanone of formula (21) , a solvent selected from
Figure imgf000198_0001
tetrahydrofuran, 1 ,4-dioxane, tert-butylmethylether, chloroform, dichloromethane, acetonitrile, ethyl ether, ethyl acetate, hexanes, N,N-dimethylformamide, dimethylsulfoxide, ethanol, tert-butanol, toluene, benzene, xylenes, and π-heptane, acetic acid, and a
Knoevenagel reaction catalyst selected from β-alanine, ammonium acetate, and piperidine, and stirring the mixture in the presence of a means of removing water selected from azeotropic distillation, activated molecular sieves, anhydrous magnesium sulfate, anhydrous cesium carbonate, trimethyl orthoformate, and triethyl orthoformate
to produce the alkene of formula (22)
Figure imgf000198_0002
b) adding the product of Step a) above to a mixture of benzylmagnesium chloride, benzylmagnesium bromide, or benzylmagnesium iodide in a solvent selected from tetrahydrofuran, 1 ,4-dioxane, hexanes, «-heptane, toluene, diethyl ether, and tert-butyl methyl ether to produce the addition products of formulas (23a)
Figure imgf000198_0003
c) adding the products of Step b) above to a mixture of a base selected from potassium hydroxide, sodium hydroxide, lithium hydroxide, and cesium hydroxide in a solvent selected from ethylene glycol,
2-methoxyethyl ether, 1 ,4-dioxane, and diethylene glycol, and stirring the mixture, and then acidifying to produce the carboxylic
acids of formulas (24a)
Figure imgf000199_0001
Figure imgf000199_0002
adding the products of Step b) above to an acid mixture selected from 6-12 M HCl, 12 M H2SO4, 10%-48% wt/wt hydrobromic acid, and HBr in aqueous acetic acid, and stirring to produce the
carboxylic acids of formulas (24a) and (24b)
Figure imgf000199_0003
Figure imgf000199_0004
contacting the products of Step c) above with an amine selected from (S)-α-methyl-benzylamine, (R)-α-methyl-benzylamine, (R)-(+)-l- (naphthyl)ethylamine, (S)-(+)- 1 -(naphthyl)ethylamine, triethylamine, diisopropylethylamine, dicyclohexylamine, benzylamine, dibenzylamine, morpholine, N-mefhylmorpholine, piperidine, N-methylpiperidine, and pyridine in a solvent selected from N,N-dimethylformamide, chloroform, hexanes, acetone, ethanol, methanol, /so-propanol, diethyl ether, dichloromethane, benzene, toluene, n-pentane, n-hexane, n-heptane, ethyl acetate, acetonitrile, tert-butyl methyl ether, tetrahydrofuran, and 1 ,4-dioxane, and recrystallizing the salt so formed to produce the enriched
Figure imgf000200_0001
salt; and e) adding the product of Step d) to a mixture selected from aqueous hydrochloric acid, aqueous sulfuric acid, aqueous acetic acid, hydrochloric acid dissolved in acetic acid, and hydrochloric acid dissolved in acetic acid and water, and stirring to produce the
carboxylic acid of formula (26) ; or
Figure imgf000200_0002
partitioning the product of Step d) between a mixture of aqueous hydrochloric acid and a solvent selected from chloroform, dichloromethane, ethyl acetate, ethyl ether, tetrahydrofuran, 1 ,4-dioxane, toluene, and tert-butylmethylether, and drying and evaporating the organic layer to produce the carboxylic acid of
formula (26)
Figure imgf000200_0003
23. A process according to Claim 21 which comprises: a) adding a cyanoacetate of formula (A)
Figure imgf000200_0004
is ethyl, to a mixture of a chiral cyclopentanone of formula (21 ) toluene, acetic acid, and a Knoevenagel reaction catalyst
Figure imgf000201_0001
which is ammonium acetate, and heating the mixture at reflux over a Dean-Stark trap to produce the alkene of formula (22)
Figure imgf000201_0002
b) adding the product of Step a) above to a mixture of benzylmagnesium chloride in dry tetrahydrofuran at -100°C to -20°C to produce the addition products of formulas (23 a)
Figure imgf000201_0003
c) adding the products of Step b) above to a mixture of potassium hydroxide in ethylene glycol, and heating the mixture at 100°C to 200°C, and then acidifying to produce the hydrolysis products of
formulas (24a) and (24b)
Figure imgf000201_0004
Figure imgf000201_0005
d) contacting the products of Step c) above with (R)-α-methyl- benzylamine in ethyl acetate, and recrystallizing the salt so formed from ethyl acetate to produce the enriched diastereomer of
Figure imgf000202_0001
benzylamine salt; and e) adding the product of Step d) to aqueous hydrochloric acid and stirring to produce the carboxylic acid of formula (26)
Figure imgf000202_0002
24. A compound of formula (6) wherein R is C| -CI Q alkyl
Figure imgf000202_0003
or C3-C1Q cycloalkyl, and pharmaceutically acceptable salts thereof.
25. A compound according to Claim 24 wherein R is C J -CI O alkyl.
26. A compound according to Claim 24 wherein R is selected from methyl, ethyl, and «-propyl.
27. A compound according to Claim 24 named ((lS,3R)-l-benzyl-3-methyl- cyclopentyl)-acetic acid. 28. A compound of formula (26) wherein R is CI -CI Q
Figure imgf000203_0001
alkyl or C3-C1 Q cycloalkyl and pharmaceutically acceptable salts thereof.
29. A compound according to Claim 28 wherein R is C]-Cι Q alkyl.
30. A compound according to Claim 28 wherein R is selected from methyl, ethyl, and rz-propyl.
31. A compound according to Claim 28 named ((lR,3S)-l-benzyl-3-methyl- cyclopentyl)-acetic acid.
32. A compound of Formula I alkyl or
Figure imgf000203_0002
R 3-C10 cycloalkyl and pharmaceutically acceptable salts thereof, prepared according to the process of Claim 1.
33. A compound according to Claim 32 wherein R is selected from methyl, ethyl, and «-propyl.
34. A compound according to Claim 32 selected from ((1R,3R)-1- aminomethyl-3-methyl-cyclopentyl)-acetic acid and ((1R,3R)-1- aminomethyl-3 -methyl-cyclopentyl)-acetic acid hydrochloride. 35. A compound of Formula II wherein R is C]-Cι Q alkyl
Figure imgf000204_0001
R or C3-C1 o cycloalkyl and pharmaceutically acceptable salts thereof, prepared according to the process of Claim 5.
36. A compound according to Claim 35 wherein R is selected from methyl, ethyl, and rø-propyl.
37. A compound according to Claim 35 selected from ((1S,3R)-1- aminomethyl-3-methyl-cyclopentyl)racetic acid and ((1 S,3R)-1- aminomethyl-3-methyl-cyclopentyl)-acetic acid hydrochloride.
38. A compound of Formula II wherein R is Ci -CJ Q alkyl
Figure imgf000204_0002
R or C3-C 10 cycloalkyl and pharmaceutically acceptable salts thereof, prepared according to the process of Claim 9.
39. A compound according to Claim 38 wherein R is selected from methyl, ethyl, and «-propyl.
40. A compound according to Claim 38 selected from ((1S,3R)-1- aminomethyl-3-methyl-cyclopentyl)-acetic acid and ((1 S,3R)-1- aminomethyl-3-methyl-cyclopentyl)-acetic acid hydrochloride. 41. A compound of Formula III wherein R is Ci -Cjo alkyl
Figure imgf000205_0001
or C3-C1 o cycloalkyl and pharmaceutically acceptable salts thereof, prepared according to the process of Claim 15.
42. A compound of Formula IV wherein R is C 1 -C 1 Q alkyl
Figure imgf000205_0002
or C3-C10 cycloalkyl and pharmaceutically acceptable salts thereof, prepared according to the process of Claim 16.
43. A compound of Formula IV wherein R is C1 -C1 Q alkyl
Figure imgf000205_0003
or C3-C10 cycloalkyl and pharmaceutically acceptable salts thereof, prepared according to the process of Claim 17.
44. A compound of formula (6) wherein R is Cj-C] Q alkyl or
Figure imgf000205_0004
C3-C10 cycloalkyl and pharmaceutically acceptable salts thereof, prepared according to the process of Claim 18. 45. A compound of formula (6) wherein R is Ci -Ci Q alkyl or
Figure imgf000206_0001
C3-C1 o cycloalkyl and pharmaceutically acceptable salts thereof, prepared according to the process of Claim 19.
46. A compound of formula (6) wherein R is C]-Cι Q alkyl or
Figure imgf000206_0002
C3-C10 cycloalkyl and pharmaceutically acceptable salts thereof, prepared according to the process of Claim 20.
Figure imgf000206_0003
3-C10 cycloalkyl and pharmaceutically acceptable salts thereof, prepared according to the process of Claim 21.
Figure imgf000206_0004
3-C10 cycloalkyl and pharmaceutically acceptable salts thereof, prepared according to the process of Claim 22. 49. A compound of formula (26) wherein R is Cι -C]Q alkyl or
Figure imgf000207_0001
C3-C1 o cycloalkyl and pharmaceutically acceptable salts thereof, prepared according to the process of Claim 23.
50. A compound selected from: E-Cyano-((R)-3-methyl-cyclopentylidene)-acetic acid ethyl ester;
Z-Cyano-((R)-3-methyl-cyclopentylidene)-acetic acid ethyl ester; (R)-((lS,3R)-l-Benzyl-3-methyl-cyclopentyl)-cyano-acetic acid ethyl ester;
(S)-((lS,3R)-l-Benzyl-3-methyl-cyclopentyl)-cyano-acetic acid ethyl ester;
(R)-((lR,3R)-l-Benzyl-3-methyl-cyclopentyl)-cyano-acetic acid ethyl ester;
(S)-(( 1 R,3 R)- 1 -Benzyl-3 -methy l-cyclopentyl)-cyano-acetic acid ethyl ester; ((lS,3R)-l-Isocyanatomethyl-3-methyl-cyclopentylmethyl)- benzene;
((1 S,3R)-1 -Benzyl-3-methyl-cyclopentylmethyl)-carbamic acid methyl ester;
[(lS,3R)-l-(Methoxycarbonylamino-methyl)-3-methyl- cyclopentyl] -acetic acid;
((lS,3R)-l-Benzyl-3-methyl-cyclopentyl)-acetic acid methyl ester; (l S,3R)-l-Methoxycarbonylmethyl-3-methyl-cyclopentyl)-acetic acid;
((lR,3R)-l-Isocyanatomethyl-3-methyl-cyclopentyl)-acetic acid methyl ester;
[(lR,3R)-l-(Methoxycarbonylamino-methyl)-3-methyl- cyclopentyl -acetic acid methyl ester; ((lS,3R)-l-Benzyl-3-methyl-cyclopentyl)-acetic acid tert-butyl ester;
[(lS,3R)-l-Carboxymethyl-3-methyl-cyclopentyl]-acetic acid tert- butyl ester; [(lS,3R)-l-Methoxycarbonylmethyl-3-methyl-cyclopentyl]-acetic acid tert-butyl ester;
((1 R,3R)-1 -Methoxycarbonylmethyl-3-methyl-cyclopentyl)-acetic acid;
((1 S,3R)-l-Isocyanatomethyl-3-methyl-cyclopentyl)-acetic acid methyl ester; and
[(lS,3R)-l-(Methoxycarbonylamino-methyl)-3-methyl- cyclopentyl]-acetic acid methyl ester.
51. A compound selected from:
((lR,3R)-l-Aminomethyl-3-methyl-cyclopentyl)-acetic acid; ((lR,3R)-l-Aminomethyl-3-methyl-cyclopentyl)-acetic acid hydrochloride;
((1R,3R)-1 -Aminomethyl-3 -ethyl-cyclopentyl)-acetic acid; (( 1 R,3R)- 1 -Aminomethyl-3 -ethyl-cyclopentyl)-acetic acid hydrochloride; ((lR,3R)-l-Aminomethyl-3-propyl-cyclopentyl)-acetic acid; and
((lR,3R)-l-Aminomethyl-3-propyl-cyclopentyl)-acetic acid hydrochloride.
52. A compound selected from:
((1 S,3R)-l-Aminomethyl-3-methyl-cyclopentyl)-acetic acid; ((lS,3R)-l-Aminomethyl-3-methyl-cyclopentyl)-acetic acid hydrochloride;
((1S,3R)-1 -Aminomethyl-3 -ethyl-cyclopentyl)-acetic acid; ((lS,3R)-l-Aminomethyl-3-ethyl-cyclopentyl)-acetic acid hydrochloride; ((l S,3R)-l-Aminomethyl-3-propyl-cyclopentyl)-acetic acid; and ((lS,3R)-l-Aminomethyl-3-propyl-cyclopentyl)-acetic acid hydrochloride.
53. A process for the preparation of a compound of formula (4a)
Q alkyl or C3-C10 cycloalkyl,
Figure imgf000209_0001
comprising, hydrolyzing a compound of formula (3 a) >
Figure imgf000209_0002
wherein R\ is H, alkyl, or benzyl.
54. A process for the preparation of a compound of formula (24a)
-Ci Q alkyl or C3-C10 cycloalkyl,
Figure imgf000209_0003
comprising, hydrolyzing a compound of formula (23a)
is H, alkyl, or benzyl.
Figure imgf000209_0004
55. A process for the preparation of a compound of formula (6)
wherein R is Ci -Ci Q alkyl or C3-C1 Q cycloalkyl,
Figure imgf000209_0005
comprising, resolving a mixture containing compounds of formulas (4a)
Figure imgf000210_0001
(4b) wherein R is Ci -CIQ alkyl or C3-C1 Q cycloalkyl.
56. A process for the preparation of a compound of formula (26)
wherein R is Ci -Ci Q alkyl or C3-C1 Q cycloalkyl,
Figure imgf000210_0003
comprising, resolving a
mixture containing compounds of formulas (24a) and
Figure imgf000210_0004
(24b) R is C1 -C iQ alkyl or C3-C10 cycloalkyl.
Figure imgf000210_0005
57. A process for the preparation of a compound of Formula I
wherein R is Ci -CJ Q alkyl or C3-C] Q cycloalkyl, and a
Figure imgf000211_0001
pharmaceutically acceptable salts thereof, comprising, hydrolyzing a
Figure imgf000211_0002
alkyl, or benzyl, and contacting the product, if desired, with an acid or a base. '
58. A process for the preparation of a compound of Formula II
wherein R is Ci -Ci Q alkyl or C3-C1 Q cycloalkyl, and
Figure imgf000211_0003
a pharmaceutically acceptable salts thereof, comprising, hydrolyzing a
compound of formula (42)
Figure imgf000211_0004
is H, alkyl, or benzyl, and contacting the product, if desired, with an acid or a base.
59. A process for the preparation of a compound of Formula III
wherein R is Cj -Ci Q alkyl or C3-C1 Q cycloalkyl, and
Figure imgf000212_0001
pharmaceutically acceptable salts thereof, comprising, hydrolyzing a
compound of formula (43) i is
Figure imgf000212_0002
H, alkyl, or benzyl, and contacting the product, if desired, with an acid or a base.
60. A process for the preparation of a compound of Formula IV
wherein R is C1 -C10 alkyl or C3-C10 cycloalkyl, and
Figure imgf000212_0003
pharmaceutically acceptable salts thereof, comprising, hydrolyzing a
compound of formula (44) is H,
Figure imgf000212_0004
alkyl, or benzyl, and contacting the product, if desired, with an acid or a base.
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