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US20060025412A1 - Peptide deformylase inhibitors - Google Patents

Peptide deformylase inhibitors Download PDF

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Publication number
US20060025412A1
US20060025412A1 US11/178,823 US17882305A US2006025412A1 US 20060025412 A1 US20060025412 A1 US 20060025412A1 US 17882305 A US17882305 A US 17882305A US 2006025412 A1 US2006025412 A1 US 2006025412A1
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Prior art keywords
butyl
methyl
hydroxyformamide
oxopyrrolidin
benzyl
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US11/178,823
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Kelly Aubart
Jia-Ning Xiang
Siegfried Christensen
Xiangmin Liao
Maxwell Cummings
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SmithKline Beecham Corp
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SmithKline Beecham Corp
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Priority claimed from PCT/US2002/006258 external-priority patent/WO2002070540A2/en
Application filed by SmithKline Beecham Corp filed Critical SmithKline Beecham Corp
Priority to US11/178,823 priority Critical patent/US20060025412A1/en
Publication of US20060025412A1 publication Critical patent/US20060025412A1/en
Priority to US11/683,089 priority patent/US7456211B2/en
Abandoned legal-status Critical Current

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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D207/00—Heterocyclic compounds containing five-membered rings not condensed with other rings, with one nitrogen atom as the only ring hetero atom
    • C07D207/02—Heterocyclic compounds containing five-membered rings not condensed with other rings, with one nitrogen atom as the only ring hetero atom with only hydrogen or carbon atoms directly attached to the ring nitrogen atom
    • C07D207/18—Heterocyclic compounds containing five-membered rings not condensed with other rings, with one nitrogen atom as the only ring hetero atom with only hydrogen or carbon atoms directly attached to the ring nitrogen atom having one double bond between ring members or between a ring member and a non-ring member
    • C07D207/22—Heterocyclic compounds containing five-membered rings not condensed with other rings, with one nitrogen atom as the only ring hetero atom with only hydrogen or carbon atoms directly attached to the ring nitrogen atom having one double bond between ring members or between a ring member and a non-ring member with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached to ring carbon atoms
    • C07D207/24—Oxygen or sulfur atoms
    • C07D207/26—2-Pyrrolidones
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D401/00—Heterocyclic compounds containing two or more hetero rings, having nitrogen atoms as the only ring hetero atoms, at least one ring being a six-membered ring with only one nitrogen atom
    • C07D401/02—Heterocyclic compounds containing two or more hetero rings, having nitrogen atoms as the only ring hetero atoms, at least one ring being a six-membered ring with only one nitrogen atom containing two hetero rings
    • C07D401/06—Heterocyclic compounds containing two or more hetero rings, having nitrogen atoms as the only ring hetero atoms, at least one ring being a six-membered ring with only one nitrogen atom containing two hetero rings linked by a carbon chain containing only aliphatic carbon atoms
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D401/00—Heterocyclic compounds containing two or more hetero rings, having nitrogen atoms as the only ring hetero atoms, at least one ring being a six-membered ring with only one nitrogen atom
    • C07D401/02—Heterocyclic compounds containing two or more hetero rings, having nitrogen atoms as the only ring hetero atoms, at least one ring being a six-membered ring with only one nitrogen atom containing two hetero rings
    • C07D401/12—Heterocyclic compounds containing two or more hetero rings, having nitrogen atoms as the only ring hetero atoms, at least one ring being a six-membered ring with only one nitrogen atom containing two hetero rings linked by a chain containing hetero atoms as chain links
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D405/00—Heterocyclic compounds containing both one or more hetero rings having oxygen atoms as the only ring hetero atoms, and one or more rings having nitrogen as the only ring hetero atom
    • C07D405/02—Heterocyclic compounds containing both one or more hetero rings having oxygen atoms as the only ring hetero atoms, and one or more rings having nitrogen as the only ring hetero atom containing two hetero rings
    • C07D405/12—Heterocyclic compounds containing both one or more hetero rings having oxygen atoms as the only ring hetero atoms, and one or more rings having nitrogen as the only ring hetero atom containing two hetero rings linked by a chain containing hetero atoms as chain links
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D413/00—Heterocyclic compounds containing two or more hetero rings, at least one ring having nitrogen and oxygen atoms as the only ring hetero atoms
    • C07D413/02—Heterocyclic compounds containing two or more hetero rings, at least one ring having nitrogen and oxygen atoms as the only ring hetero atoms containing two hetero rings
    • C07D413/06—Heterocyclic compounds containing two or more hetero rings, at least one ring having nitrogen and oxygen atoms as the only ring hetero atoms containing two hetero rings linked by a carbon chain containing only aliphatic carbon atoms
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D417/00—Heterocyclic compounds containing two or more hetero rings, at least one ring having nitrogen and sulfur atoms as the only ring hetero atoms, not provided for by group C07D415/00
    • C07D417/02—Heterocyclic compounds containing two or more hetero rings, at least one ring having nitrogen and sulfur atoms as the only ring hetero atoms, not provided for by group C07D415/00 containing two hetero rings
    • C07D417/06—Heterocyclic compounds containing two or more hetero rings, at least one ring having nitrogen and sulfur atoms as the only ring hetero atoms, not provided for by group C07D415/00 containing two hetero rings linked by a carbon chain containing only aliphatic carbon atoms

Definitions

  • the present invention relates to the use of novel anti-bacterial compounds, and pharmaceutical compositions containing these compounds as peptide deformylase inhibitors.
  • Bacterial initiator methionyl tRNA is modified by methionyl tRNA formyltransferase (FMT) to produce formyl-methionyl tRNA.
  • FMT methionyl tRNA formyltransferase
  • the formyl methionine (f-met) is then incorporated at the N-termini of newly synthesized polypeptides.
  • Polypeptide deformylase PDF or Def
  • PDF deformylates primary translation products to produce N-methionyl polypeptides.
  • Most intracellular proteins are further processed by methionine amino peptidase (MAP) to yield the mature peptide and free methionine, which is recycled.
  • PDF and MAP are both essential for bacterial growth, and PDF is required for MAP activity. This series of reactions is referred to as the methionine cycle ( FIG. 1 ).
  • polypeptide deformylase homologous genes have been found in bacteria, in chloroplast-containing plants, in mice and in humans.
  • the plant proteins are nuclear encoded but appear to carry a chloroplast localisation signal. This is consistent with the observation that chloroplast RNA and protein synthesis processes are highly similar to those of eubacteria. While there is limited information on protein expression of mammalian PDF gene homologs (Bayer Aktiengesellschaft, Pat. WO2001/42431), no functional role for such proteins has been demonstrated to date (Meinnel, T., Parasitology Today 16(4), 165-168, 2000).
  • Polypeptide deformylase is found in all eubacteria for which high coverage genomic sequence information is available. Sequence diversity among PDF homologs is high, with as little as 20% identity between distantly related sequences. However, conservation around the active site is very high, with several completely conserved residues, including one cysteine and two histidines which are required to coordinate the active site metal (Meinnel, T. et al, 1997, Journal of Molecular Biology, 267, 749-761).
  • PDF is recognized to be an attractive anti-bacterial target, as this enzyme has been demonstrated to be essential for bacterial growth in vitro (Mazel, D. et al, EMBO J. 13 (4), 914-923, 1994), is not believed to be involved in eukaryotic protein synthesis (Rajagopalan et al, J. Am. Chem. Soc. 119, 12418-12419, 1997), and is universally conserved in prokaryotes (Kozak, M., Microbiol. Rev. 47, 1-45, 1983). Therefore PDF inhibitors can potentially serve as broad spectrum anti-bacterial agents.
  • the present invention involves novel anti-bacterial compounds represented by Formula (I) hereinbelow and their use as PDF inhibitors.
  • FIG. 1 Provides a graph of the methionine cycle.
  • alkyl refers to a hydrocarbon group joined together by single carbon-carbon bonds.
  • the alkyl hydrocarbon group may be linear, branched or cyclic.
  • Preferred compounds useful in the present invention are selected from the group consisting of:
  • compositions and complexes such as the hydrochloride, hydrobromide and trifluoroacetate salts, and the sodium, potassium, and magnesium salts.
  • the compounds of the present invention may contain one or more asymmetric carbon atoms and may exist in racemic and optically active forms. All of these compounds and diastereomers are contemplated to be within the scope of the present invention.
  • the present invention provides compounds of formula (I): that can be prepared by a process consisting of:
  • a compound of Formula (5) can be converted to a compound of Formula (6) wherein R2 is other than H through an alkylation reaction.
  • the lactam nitrogen of a compound of Formula (5) can be protected using an appropriate protecting group, such as a Boc group, under standard conditions to give a versatile intermediate of Formula (11).
  • Conversion of a lactam of Formula (11) to the ⁇ -formyl lactam of Formula (12) can be achieved by treatment of an enolate generated from a lactam of Formula (11) with an appropriate formylating agent such as isopropyl formate, or alternatively, by using Bredereck's reagent followed by acidic hydrolysis.
  • an appropriate formylating agent such as isopropyl formate
  • a compound of Formula (12) can be derived from the Boc-protected ⁇ , ⁇ -unsaturated pyrrolidinone (13) through 1,4-addition with an organometallic reagent, such as R1MgX, followed by quenching with an electrophile, such as isopropyl formate or methyl bromoacetate.
  • an organometallic reagent such as R1MgX
  • a lactam of Formula (16) is then readily converted to the target compound of Formula (I) by treatment with an alkyl halide, a sulfonyl chloride, an acid chloride or an isocyanate followed by deprotection of the benzyl group under hydrogenolysis conditions.
  • an unsaturated lactone of Formula (17) with, e.g., a Grignard reagent R1MgX in the presence of catalytic ammount of a copper salt, such as copper (I) bromide, HMPA and chlorotrimethylsilane at an appropriate temperature, affords a lactone of Formula (18).
  • a Grignard reagent R1MgX in the presence of catalytic ammount of a copper salt, such as copper (I) bromide, HMPA and chlorotrimethylsilane at an appropriate temperature
  • the lactone ring in a compound of Formula (18) can be hydrolyzed using appropriate base, such as sodium hydroxide.
  • appropriate base such as sodium hydroxide.
  • the resulting carboxylate is then coupled with an amine of Formula (19) followed an intramolecular cyclization to afford a lactam of Formula (6).
  • a lactone of Formula (18) is treated with a base, such as lithium diisopropylamine, and chloromethyl benzyl ether to give a compound of Formula (20).
  • a lactone of Formula (20) is then converted to a lactam of Formula (21) under similar conditions described above for conversion of a compound of Formula (18) to a compound of Formula (6).
  • An optically active compound of Formula (I) can be prepared by treating a lactone of Formula (18) with a chiral amine, such as (S)-methylphenyl amine, in the presence of a catalyst, such as 2-hydroxypyridine, in a suitable solvent, such as toluene, at reflux to afford a mixture of two diastereomers of Formula (22) and (23), which can be readily separated by silica gel flash column chromatography.
  • a chiral amine such as (S)-methylphenyl amine
  • a catalyst such as 2-hydroxypyridine
  • Intramolecular Mitsunobu reaction of a compound of Formula (22) or (23), followed by removal of the N-protecting group with sodium in liquid ammonia affords an optically pure lactam of formula (24) or (25), respectively.
  • Conversion of a chiral lactam of Formula (24) or (25) to the chiral target compound of Formula (I) can then be achieved using reagents and conditions described above for transformation of a compound of Formula (5) to a compound of Formula (1).
  • a chiral lactone of Formula (26) or (27) can then be converted to the chiral target compound of Formula (I).
  • the first eluted fraction was (S)-3-hydroxymethylheptanoic acid, (S)-1-phenylethylamide (2.8 g, 39%) which is used in Example 2.
  • 1 H NMR (CDCl 3 ) ⁇ 7.33 (m, 5 H), 6.07 (bs, 1 H), 5.11 (q, 1 H), 3.63 ,(m, 1 H), 3.48 (m, 1 H), 3.29 (bs, 1 H), 2.29 (m, 2 H), 1.95 (m, 1 H), 1.50 (d, 2 H), 1.28 (m, 6 H), 0.88 (t, 3 H).
  • MS(ES) m/e 264 [M+H] + .
  • the mixture was extracted with ethyl acetate (3 ⁇ 10 mL) and the combined organic extracts were dried (Na 2 SO 4 ), filtered, and concentrated.
  • the residue was dissolved in dry pyridine (5 mL), and treated with benzyloxyamine hydrochloride (0.13 g, 0.79 mmol) at room temperature for 2 h. After removing the solvent under reduced pressure, the residue was dissolved in acetic acid (5 mL) and treated with NaCNBH 3 (0.22 g, 1.03 mmol) at room temperature for 2 h.
  • the mixture was diluted with ethyl acetate (10 mL) and neutralized with 10% aqueous NaOH.
  • Example 1(a)-1(f) Following the procedure of Example 1(a)-1(f), except substituting (R)-1-(5-benzyloxypentyl)4-butylpyrrolidin-2-one with (S)-1-(5-benzyloxypentyl)-4-butylpyrrolidin-2-one, the title compound was prepared. It has the identical 1 H NMR and MS as the compound of Example 1(f).
  • a compound of the Formula (1) or a pharmaceutically acceptable salt thereof for the treatment of humans and other mammals, it is normally formulated in accordance with standard pharmaceutical practice as a pharmaceutical composition.
  • the present compounds are useful for the treatment of bacterial infections including, but not limited to, respiratory tract infections and/or Gram positive infections.
  • Compounds of Formula (I) and their pharmaceutically acceptable salts may be administered in a standard manner for antibiotics, for example orally, parenterally, sub-lingually, dermally, transdermally, rectally, via inhalation or via buccal administration.
  • compositions of Formula (I) and their pharmaceutically acceptable salts which are active when given orally can be formulated as syrups, tablets, capsules, creams and lozenges.
  • a syrup formulation will generally consist of a suspension or solution of the compound or salt in a liquid carrier for example, ethanol, peanut oil, olive oil, glycerine or water with a flavoring or coloring agent.
  • a liquid carrier for example, ethanol, peanut oil, olive oil, glycerine or water with a flavoring or coloring agent.
  • any pharmaceutical carrier routinely used for preparing solid formulations may be used. Examples of such carriers include magnesium stearate, terra alba, talc, gelatin, acacia, stearic acid, starch, lactose and sucrose.
  • composition is in the form of a capsule
  • any routine encapsulation is suitable, for example using the aforementioned carriers in a hard gelatin capsule shell.
  • composition is in the form of a soft gelatin shell capsule
  • any pharmaceutical carrier routinely used for preparing dispersions or suspensions may be considered, for example aqueous gums, celluloses, silicates or oils, and are incorporated in a soft gelatin capsule shell.
  • Typical parenteral compositions consist of a solution or suspension of a compound or salt in a sterile aqueous or non-aqueous carrier optionally containing a parenterally acceptable oil, for example polyethylene glycol, polyvinylpyrrolidone, lecithin, arachis oil or sesame oil.
  • a parenterally acceptable oil for example polyethylene glycol, polyvinylpyrrolidone, lecithin, arachis oil or sesame oil.
  • compositions for inhalation are in the form of a solution, suspension or emulsion that may be administered as a dry powder or in the form of an aerosol using a conventional propellant such as dichlorodifluoromethane or trichlorofluoromethane.
  • a typical suppository formulation comprises a compound of Formula (I) or a pharmaceutically acceptable salt thereof which is active when administered in this way, with a binding and/or lubricating agent, for example polymeric glycols, gelatins, cocoa-butter or other low melting vegetable waxes or fats or their synthetic analogs.
  • a binding and/or lubricating agent for example polymeric glycols, gelatins, cocoa-butter or other low melting vegetable waxes or fats or their synthetic analogs.
  • Typical dermal and transdermal formulations comprise a conventional aqueous or non-aqueous vehicle, for example a cream, ointment, lotion or paste or are in the form of a medicated plaster, patch or membrane.
  • the composition is in unit dosage form, for example a tablet, capsule or metered aerosol dose, so that the patient may administer a single dose.
  • Each dosage unit for oral administration contains suitably from 0.1 mg to 500 mg/Kg, and preferably from 1 mg to 100 mg/Kg, and each dosage unit for parenteral administration contains suitably from 0.1 mg to 100 mg/Kg, of a compound of Formula(I) or a pharmaceutically acceptable salt thereof calculated as the free acid.
  • Each dosage unit for intranasal administration contains suitably 1-400 mg and preferably 10 to 200 mg per person.
  • a topical formulation contains suitably 0.01 to 5.0% of a compound of Formula (1).
  • the daily dosage regimen for oral administration is suitably about 0.01 mg/Kg to 40 mg/Kg, of a compound of Formula(I) or a pharmaceutically acceptable salt thereof calculated as the free acid.
  • the daily dosage regimen for parenteral administration is suitably about 0.001 mg/Kg to 40 mg/Kg, of a compound of Formula (I) or a pharmaceutically acceptable salt thereof calculated as the free acid.
  • the daily dosage regimen for intranasal administration and oral inhalation is suitably about 10 to about 500 mg/person.
  • the active ingredient may be administered from 1 to 6 times a day, sufficient to exhibit the desired activity.
  • S. aureus or E. coli PDF activity is measured at 25° C., using a continuous enzyme-linked assay developed by Lazennec & Meinnel, (1997) “Formate dehydrogenase-coupled spectrophotometric assay of peptide deformylase” Anal. Biochem 244, pp. 180-182, with minor modifications.
  • the reaction mixture is contained in 50 uL with 50 mM potassium phosphate buffer (pH7.6), 15 mM NAD, 0.25 U formate dehydrogenase.
  • the substrate peptide, f-Met-Ala-Ser is included at the K M concentration.
  • the reaction is triggered with the addition of 10 nM Def1 enzyme, and absorbance is monitored for 20 min at 340 nm.
  • This panel consisted of the following laboratory strains: Staphylococcus aureus Oxford, Staphylococcus aureus WCUH29, Enterococcus faecalis I, Enterococcus faecalis 7, Haemophilus influenzae Q1, Haemophilus influenzae NEMC1, Moraxella catarrhalis 1502, Streptococcus pneumoniae 1629, Streptococcus pneumoniae N1387, Streptococcus pneumoniae N1387, E. coli 7623 (AcrABEFD+) and E. coli 120 (AcrAB ⁇ ).
  • the minimum inhibitory concentration (MIC) was determined as the lowest concentration of compound that inhibited visible growth. A mirror reader was used to assist in determining the MIC endpoint.

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Abstract

PDF inhibitors and novel methods for their use are provided.

Description

    FIELD OF THE INVENTION
  • The present invention relates to the use of novel anti-bacterial compounds, and pharmaceutical compositions containing these compounds as peptide deformylase inhibitors.
    • BACKGROUND OF THE INVENTION
  • Bacterial initiator methionyl tRNA is modified by methionyl tRNA formyltransferase (FMT) to produce formyl-methionyl tRNA. The formyl methionine (f-met) is then incorporated at the N-termini of newly synthesized polypeptides. Polypeptide deformylase (PDF or Def) then deformylates primary translation products to produce N-methionyl polypeptides. Most intracellular proteins are further processed by methionine amino peptidase (MAP) to yield the mature peptide and free methionine, which is recycled. PDF and MAP are both essential for bacterial growth, and PDF is required for MAP activity. This series of reactions is referred to as the methionine cycle (FIG. 1).
  • To date, polypeptide deformylase homologous genes have been found in bacteria, in chloroplast-containing plants, in mice and in humans. The plant proteins are nuclear encoded but appear to carry a chloroplast localisation signal. This is consistent with the observation that chloroplast RNA and protein synthesis processes are highly similar to those of eubacteria. While there is limited information on protein expression of mammalian PDF gene homologs (Bayer Aktiengesellschaft, Pat. WO2001/42431), no functional role for such proteins has been demonstrated to date (Meinnel, T., Parasitology Today 16(4), 165-168, 2000).
  • Polypeptide deformylase is found in all eubacteria for which high coverage genomic sequence information is available. Sequence diversity among PDF homologs is high, with as little as 20% identity between distantly related sequences. However, conservation around the active site is very high, with several completely conserved residues, including one cysteine and two histidines which are required to coordinate the active site metal (Meinnel, T. et al, 1997, Journal of Molecular Biology, 267, 749-761).
  • PDF is recognized to be an attractive anti-bacterial target, as this enzyme has been demonstrated to be essential for bacterial growth in vitro (Mazel, D. et al, EMBO J. 13 (4), 914-923, 1994), is not believed to be involved in eukaryotic protein synthesis (Rajagopalan et al, J. Am. Chem. Soc. 119, 12418-12419, 1997), and is universally conserved in prokaryotes (Kozak, M., Microbiol. Rev. 47, 1-45, 1983). Therefore PDF inhibitors can potentially serve as broad spectrum anti-bacterial agents.
    • SUMMARY OF THE INVENTION
  • The present invention involves novel anti-bacterial compounds represented by Formula (I) hereinbelow and their use as PDF inhibitors.
    • BRIEF DESCRIPTION OF THE DRAWINGS
  • FIG. 1: Provides a graph of the methionine cycle.
    • DETAILED DESCRIPTION OF THE INVENTION
  • The compounds useful in the present methods are selected from Formula (I) hereinbelow:
    Figure US20060025412A1-20060202-C00001
    wherein:
    • R1 is selected from the group consisting of: C1-6alkyl, —C1-2alkylAr, and Ar;
    • R2 is selected from the group consisting of hydrogen, C1-6alkyl, —(CH2)mOH, —(CH2)nAr′, —(CH2)nHet, —Ar′, —SO2R3, —C(O)R3, —C(O)NHR3, —C(O)OR3, —CH(R4)CONR5R6, and —CH(R4)CO2R7;
    • R3 is selected from the group consisting of: C1-6alkyl, —C1-2alkylAr′, and Ar′;
    • R4 is hydrogen, or C1-6alkyl;
    • R5 and R6 are independently selected from the group consisting of hydrogen, C1-6alkyl, —C1-2alkylAr′, and Ar′; or R5, R6 together form a five or six membered cycloalkyl ring which is optionally mono-substituted by —CH2OR7;
    • R7 is selected from the group consisting of hydrogen, and C1-3alkyl;
    • Ar is selected from the group consisting of phenyl, furyl, and thienyl, all of which may be optionally substituted by one or more Z1 groups;
    • Ar′ is selected from the group consisting of: phenyl, naphthyl, furyl, pyridyl, thienyl, thiazolyl, isothiazolyl, pyrazolyl, triazolyl, tetrazolyl, imidazolyl, imidazolidinyl, benzofuranyl, indolyl, thiazolidinyl, isoxazolyl, oxadiazolyl, thiadiazolyl, morpholinyl, piperidinyl, piperazinyl, pyrrolyl, and pyrimidyl, all of which may be optionally substituted by one or more Z2 groups;
    • Het is selected from the group consisting of tetrahydrofuranyl and piperidinyl;
    • Z1 is independently selected from the group consisting of C1-3alkyl, —CN, F, Cl, Br, and I;
    • Z2 is independently selected from the group consisting of C1-6alkyl, —OR2, —(CH2)nCO2R4, —C(O)NR5R6, —CN, —(CH2)nOH, —NO2, F, Cl, Br, I, —NR5R6, and —NHC(O)R 1;
    • m is 2 to 5; and
    • n is 0 to 5.
  • As used herein, “alkyl” refers to a hydrocarbon group joined together by single carbon-carbon bonds. The alkyl hydrocarbon group may be linear, branched or cyclic.
  • Preferred compounds useful in the present invention are selected from the group consisting of:
    • (3S,4R)—N-[4-Butyl-1-(5-hydroxypentyl)-2-oxopyrrolidin-3-yl-methyl]-N-hydroxyformamide;
    • (3R,4S)—N-[4-Butyl-1-(5-hydroxypentyl)-2-oxopyrrolidin-3-yl-methyl]-N-hydroxyformamide;
    • (±)-(3RS,4SR)—N-[4-Butyl-2-oxo-1-(t-butylcarboxy)pyrrolidin-3-yl-methyl]-N-hydroxyformamide;
    • (±)-(3RS,4SR)—N-(4-Butyl-2-oxopyrrolidin-3-yl-methyl)-N-hydroxyformamide;
    • (±)-(3RS,4SR)—N-(4-Butyl-2-oxo-1-pentanoylpyrrolidin-3-yl-methyl)-N-hydroxyformamide;
    • (±)-(3RS,4SR)—N-[4-Butyl-2-oxo-1-(2-phenylethanoyl)pyrrolidin-3-yl-methyl]-N-hydroxyformamide;
    • (±)-(3RS,4SR)—N-[4-Butyl-2-oxo-1-(1-phenylmethanoyl)pyrrolidin-3-yl-methyl]-N-hydroxyformamide;
    • (±)-(3RS,4SR)—N-(1-Benzenesulfonyl-4-butyl-2-oxopyrrolidin-3-yl-methyl)-N-hydroxyformamide;
    • (±)-(3RS,4SR)—N-[1-(Butane-1-sulfonyl)-4-butyl-2-oxopyrrolidin-3-yl-methyl]-N-hydroxyformamide;
    • (±)-(3RS,4SR)—N-[4-Butyl-1-(naphthalen-2-ylmethanoyl)-2-oxopyrrolidin-3-yl-methyl]-N-hydroxyformamide;
    • (±)-(3RS,4SR)—N-(1-Benzyl-4-butyl-2-oxopyrrolidin-3-yl-methyl)-N-hydroxyformamide;
    • (±)-(3RS,4SR)—N-{4-Butyl-1-[1-(4-ethoxyphenyl)methanoyl]-2-oxopyrrolidin-3-yl-methyl}-N-hydroxyformamide;
    • (±)-(3RS,4SR)—N-{4-Butyl-1-[1-(3-ethoxyphenyl)methanoyl]-2-oxopyrrolidin-3-yl-methyl}-N-hydroxyformamide;
    • (±)-(3RS,4SR)—N-{4-Butyl-1-[1-(2-ethoxyphenyl)methanoyl]-2-oxopyrrolidin-3-yl-methyl}-N-hydroxyformamide;
    • (±)-(3RS,4SR)—N-(4-Butyl-2-oxo-1-pyridin-3-ylmethylpyrrolidin-3-yl-methyl)-N-hydroxyformamide;
    • N-((3S,4R)-4-Butyl-1-{(S)-1-[1-((S)-2-methoxymethylpyrrolidin-1-yl)methanoyl]-3-methylbutyl}-2-oxopyrrolidin-3-yl-methyl)-N-hydroxyformamide;
    • N-((3R,4S)-4-Butyl-1-{(S)-1-[1-((S)-2-methoxymethylpyrrolidin-1-yl)methanoyl]-3-methylbutyl}-2-oxopyrrolidin-3-yl-methyl)-N-hydroxyformamide;
    • N-((3S,4R)-4-Butyl-1-{(S)-1-[1-(dimethylamino)methanoyl]-3,3-dimethylbutyl}-2-oxopyrrolidin-3-yl-methyl)-N-hydroxyformamide;
    • (±)-(3RS,4SR)—N-[4-Butyl-1-(4-ethoxybenzyl)-2-oxopyrrolidin-3-yl-methyl]-N-hydroxyformamide;
    • (±)-(3RS,4SR)—N-[4-Butyl-1-(4-hydroxybenzyl)-2-oxopyrrolidin-3-yl-methyl]-N-hydroxyformamide;
    • (±)-(3RS,4SR)—N-{4-Butyl-1-[4-(2-morpholin-4-yl-2-oxoethoxy)benzyl]-2-oxopyrrolidin-3-yl-methyl}-N-hydroxyformamide;
    • (±)-(3RS,4SR)—N-{4-Butyl-1-[4-(4-carboxy-1-butoxy)benzyl]-2-oxopyrrolidin-3-yl-methyl}-N-hydroxyformamide;
    • (±)-(3RS,4SR)—N-{4-Butyl-1-[4-(3-hydroxybenzoxy)benzyl]-2-oxopyrrolidin-3-yl-methyl}-N-hydroxyformamide;
    • (±)-(3RS,4SR)—N-{4-Butyl-2-oxo-1-[4-(tetrahydrofuran-2-ylmethoxy)benzyl]-pyrrolidin-3-yl-methyl}-N-hydroxyformamide;
    • (±)-(3RS,4SR)—N-{4-Butyl-1-[4-(furan-2-ylmethoxy)benzyl]-2-oxopyrrolidin-3-yl-methyl}-N-hydroxyformamide;
    • (±)-(3RS,4SR)—N-{4-Butyl-1-[4-(3-hydroxypropoxy)benzyl]-2-oxopyrrolidin-3-yl-methyl}-N-hydroxyformamide;
    • (±)-(3RS,4SR)—N-{4-Butyl-2-oxo-1-[4-(piperidin-3-ylmethoxy)benzyl]pyrrolidin-3-yl-methyl}-N-hydroxyformamide;
    • (±)-(3RS,4SR)—N-{4-Butyl-2-oxo-1-[4-(pyridin-3-ylmethoxy)benzyl]pyrrolidin-3-yl-methyl}-N-hydroxyformamide;
    • (±)-(3RS,4SR)—N-{4-Butyl-1-[4-(5-hydroxypentoxy)benzyl]-2-oxopyrrolidin-3-yl-methyl}-N-hydroxyformamide; and
    • (±)-(3RS,4SR)—N-[4-Butyl-1-(2,3-dichlorobenzyl)-2-oxopyrrolidin-3-yl-methyl]-N-hydroxyformamide;
    • (±)-(3RS,4SR)—N-[4-Butyl-1-(3,4-dichlorobenzyl)-2-oxopyrrolidin-3-yl-methyl]-N-hydroxyformamide;
    • (±)-(3RS,4SR)—N-(4-Butyl-2-oxo-1-phenylpyrrolidin-3-y-methyl]-N-hydroxyformamide;
    • (±)-(3RS,4SR)—N-{4-Butyl-1-[2-(2-hydroxyphenyl)-2-oxoethyl]-2-oxopyrrolidin-3-yl-methyl}-N-hydroxyformamide;
    • (±)-(3RS,4SR)—N-[4-Butyl-1-(3,5-dimethylisoxazol-4-ylmethyl)-2-oxopyrrolidin-3-yl-methyl]-N-hydroxyformamide;
    • (±)-(3RS,4SR)—N-[4-Butyl-1-(2-methylthiazol-4-ylmethyl)-2-oxopyrrolidin-3-yl-methyl]-N-hydroxyformamide.
  • Also included in the present invention are pharmaceutically acceptable salts and complexes, such as the hydrochloride, hydrobromide and trifluoroacetate salts, and the sodium, potassium, and magnesium salts. The compounds of the present invention may contain one or more asymmetric carbon atoms and may exist in racemic and optically active forms. All of these compounds and diastereomers are contemplated to be within the scope of the present invention.
  • The compounds and processes of the present invention will be better understood in connection with the following synthetic schemes, which are merely illustrative of the methods by which the compounds of the invention may be prepared and are not intended to limit the scope of the invention as defined in the appended claims.
  • The present invention provides compounds of formula (I):
    Figure US20060025412A1-20060202-C00002
    that can be prepared by a process consisting of:
    • treating an aldehyde of Formula (2)
      R1CHO   (2)
      with Ph3P═CHCO2Et in a solvent, such as tetrahydrofuran, to give an α,β-unsaturated ester of Formula (3).
      Figure US20060025412A1-20060202-C00003
  • Treatment of a compound of Formula (3) with nitromethane in the presence of Triton B leads to a Michael addition product of Formula (4).
    Figure US20060025412A1-20060202-C00004
  • Reduction of the nitro group in a compound of Formula (4) under hydrogenolysis conditions followed by an intramolecular cyclization, at appropriate temperature in an appropriate solvent, such as toluene, affords a lactam of Formula (5).
    Figure US20060025412A1-20060202-C00005
  • A compound of Formula (5) can be converted to a compound of Formula (6) wherein R2 is other than H through an alkylation reaction.
    Figure US20060025412A1-20060202-C00006
  • Treatment of an enolate generated from a lactam of Formula (6) with an appropriate formylating agent, such as isopropyl formate, in an appropriate solvent, such as dry tetrahydrofuran, affords an aldehyde of Formula (7).
    Figure US20060025412A1-20060202-C00007
  • Coupling of an aldehyde of Formula (7) with a suitable reagent, such as benzyloxyamine hydrochloride, in a suitable solvent, such as dry pyridine, affords a compound of Formula (8).
    Figure US20060025412A1-20060202-C00008
  • Reduction of a compound of Formula (8) with a suitable reagent, such as sodium cyanoborohydride, in an appropriate solvent, such as acetic acid, affords a compound of Formula (9).
    Figure US20060025412A1-20060202-C00009
  • Formylation of a compound of Formula (9) with a suitable reagent, such as formyl acetyl anhydride, in a suitable solvent, such as methylene chloride, affords a compound of Formula (10).
    Figure US20060025412A1-20060202-C00010
  • Removal of the protecting group(s) in a compound of Formula (10) affords a compound of Formula (I).
  • Alternatively, the lactam nitrogen of a compound of Formula (5) can be protected using an appropriate protecting group, such as a Boc group, under standard conditions to give a versatile intermediate of Formula (11).
    Figure US20060025412A1-20060202-C00011
  • Conversion of a lactam of Formula (11) to the α-formyl lactam of Formula (12) can be achieved by treatment of an enolate generated from a lactam of Formula (11) with an appropriate formylating agent such as isopropyl formate, or alternatively, by using Bredereck's reagent followed by acidic hydrolysis.
    Figure US20060025412A1-20060202-C00012
  • Alternatively, a compound of Formula (12) can be derived from the Boc-protected α,β-unsaturated pyrrolidinone (13) through 1,4-addition with an organometallic reagent, such as R1MgX, followed by quenching with an electrophile, such as isopropyl formate or methyl bromoacetate.
    Figure US20060025412A1-20060202-C00013
  • Reductive amination of an aldehyde of Formula (12) with sodium cyanoborohydride and an amine, such as benzyloxyamine, in a suitable solvent provides an amine of Formula (14).
    Figure US20060025412A1-20060202-C00014
  • Treatment of a compound of Formula (14) with formic acid in the presence of acetic anhydride and triethylamine provides a compound of Formula (15).
    Figure US20060025412A1-20060202-C00015
  • Removal of the Boc group compounds of Formula (15) using an appropriate acid, such as trifluoroacetic acid, gives a compound of Formula (16).
    Figure US20060025412A1-20060202-C00016
  • A lactam of Formula (16) is then readily converted to the target compound of Formula (I) by treatment with an alkyl halide, a sulfonyl chloride, an acid chloride or an isocyanate followed by deprotection of the benzyl group under hydrogenolysis conditions.
  • Alternatively, treating an unsaturated lactone of Formula (17)
    Figure US20060025412A1-20060202-C00017
    with, e.g., a Grignard reagent R1MgX in the presence of catalytic ammount of a copper salt, such as copper (I) bromide, HMPA and chlorotrimethylsilane at an appropriate temperature, affords a lactone of Formula (18).
    Figure US20060025412A1-20060202-C00018
  • Treatment of a lactone of Formula (18) with an amine of Formula (19)
    R2-NH2   (19)
    in a suitable solvent, such as toluene in the presence of a Lewis acid, such as AlMe3, followed by an intramolecular cyclization under Mitsunobu conditions, affords a lactam of Formula (6).
  • Alternatively, the lactone ring in a compound of Formula (18) can be hydrolyzed using appropriate base, such as sodium hydroxide. The resulting carboxylate is then coupled with an amine of Formula (19) followed an intramolecular cyclization to afford a lactam of Formula (6).
  • Alternatively, a lactone of Formula (18) is treated with a base, such as lithium diisopropylamine, and chloromethyl benzyl ether to give a compound of Formula (20).
    Figure US20060025412A1-20060202-C00019
    A lactone of Formula (20) is then converted to a lactam of Formula (21) under similar conditions described above for conversion of a compound of Formula (18) to a compound of Formula (6).
    Figure US20060025412A1-20060202-C00020
  • Removal of the benzyl group in a compound of Formula (21) followed by oxidation of the alcohol using an appropriate oxidant, such as Dess-Martin reagent, affords an aldehyde of Formula (7).
  • An optically active compound of Formula (I) can be prepared by treating a lactone of Formula (18) with a chiral amine, such as (S)-methylphenyl amine, in the presence of a catalyst, such as 2-hydroxypyridine, in a suitable solvent, such as toluene, at reflux to afford a mixture of two diastereomers of Formula (22) and (23), which can be readily separated by silica gel flash column chromatography.
    Figure US20060025412A1-20060202-C00021
  • Intramolecular Mitsunobu reaction of a compound of Formula (22) or (23), followed by removal of the N-protecting group with sodium in liquid ammonia affords an optically pure lactam of formula (24) or (25), respectively.
    Figure US20060025412A1-20060202-C00022
    Conversion of a chiral lactam of Formula (24) or (25) to the chiral target compound of Formula (I) can then be achieved using reagents and conditions described above for transformation of a compound of Formula (5) to a compound of Formula (1).
  • Alternatively, treatment of a compound of Formula (22) or (23) with an appropriate acid, e.g., 1 M H2SO4, in an appropriate solvent, such as dioxane, affords a chiral lactone of Formula (26) or (27), respectively.
    Figure US20060025412A1-20060202-C00023
  • Using reagents and conditions described above for transformation of a compound of Formula (18) to a compound of Formula (I), a chiral lactone of Formula (26) or (27) can then be converted to the chiral target compound of Formula (I).
  • The present compounds are further exemplified by the following Examples which are intended to be illustrative of the present invention and not limiting in any way.
    • EXAMPLE 1 Preparation of N-[(3S,4R)4-Butyl-1-(5-hydroxypentyl)-2-oxopyrrolidin-3-yl-methyl]-N-hydroxyformamide 1(a) (R)-3-Hydroxymethylheptanoic acid, (S)-1-phenylethylamide
  • A mixture of (±)-4-butyldihydrofuran-2-one (3.9 g, 27.4 mmol), 2-hydroxypyridine (3.1 g, 32.9 mmol) and (S)-1-phenylethylamine (7.8 mL, 60.3 mmol) in dry toluene (50 mL) was heated to reflux overnight. The reaction mixture was cooled to room temperature and diluted with ethyl acetate (100 mL), washed with 1 N HCl (2×50 mL) and brine (50 mL), dried (Na2SO4), and concentrated. The residue was purified by flash column chromatography (silica gel, 4:1 EtOAc/hexanes) to afford two compounds as white solids. The first eluted fraction was (S)-3-hydroxymethylheptanoic acid, (S)-1-phenylethylamide (2.8 g, 39%) which is used in Example 2. 1H NMR (CDCl3) δ 7.33 (m, 5 H), 6.07 (bs, 1 H), 5.11 (q, 1 H), 3.63 ,(m, 1 H), 3.48 (m, 1 H), 3.29 (bs, 1 H), 2.29 (m, 2 H), 1.95 (m, 1 H), 1.50 (d, 2 H), 1.28 (m, 6 H), 0.88 (t, 3 H). MS(ES) m/e 264 [M+H]+. The second eluted fraction (R)-3-hydroxymethylheptanoic acid, (S)-1-phenylethylamide (2.6 g, 36%). 1H NMR (CDCl3) δ 7.29 (m, 5 H), 6.34 (bs, 1 H), 5.09 (q, 1 H), 3.64 (m, 1 H), 3.57 (bs, 1 H), 3.48 (m, 1 H), 2.28 (m, 2 H), 1.93 (m, 1 H), 1.48 (d, 2 H), 1.28 (m, 6 H), 0.88 (t, 3 H). MS(ES) m/e 264 [M+H]+.
    • 1(b) (R)-4-Butyl-1-[(S)-1-phenylethyl]pyrrolidin-2-one
  • To a solution of di-t-butyl azodicarboxylate (2.1 g, 9.1 mmol) in tetrahydrofuran (25 mL) under argon was added tributylphosphine (2.27 mL, 9.1 mmol). The mixture was stirred for 5 minutes and was added slowly to a solution of (R)-3-hydroxymethylheptanoic acid, (S)-1-phenylethylamide (1.84 g, 7.0 mmol) in dry THF (10 mL) at 0° C. The reaction was warmed up to rt and stirred overnight. Saturated NaHCO3 (100 mL) was added and the resulting mixture was extracted with CH2Cl2 (2×100 mL). The combined organic extracts were dried (Na2SO4), filtered and concentrated. The residue was purified by flash column chromatography (silica gel, 1:4 EtOAc/hexanes) to afford 1.4 g (82%) of (R)-4-butyl-1-[(S)-1-phenylethyl]pyrrolidin-2-one as a colorless oil: 1H NMR (CDCl3) δ 7.33 (m, 5 H), 5.48 (q, 1 H), 3.06 (t, 1 H), 2.92 (t, 1 H), 2.53 (q, 1 H), 2.06 (m, 2 H), 1.51 (d, 3 H), 1.20-1.46 (m, 6 H), 0.88 (t, 3 H). MS(ES) m/e 246 [M+H]+.
    • 1(c) (R)-4-Butylpyrrolidin-2-one
  • To a solution of (R)-4-butyl-1-[(S)-1-phenylethyl]pyrrolidin-2-one (1.4 g, 5.7 mmol) in dry tetrahydrofuran (10 mL) at −78° C. was added condensed liquid ammonia (100 mL). Freshly cut sodium (0.66 g, 28.5 mmol) was added and the resulting mixture was stirred at −78° C. for 2 h. The reaction was quenched with solid ammonium chloride. Ammonia was evaporated by warming up the reaction mixture slowly to room temperature. Water (50 mL) was added and the mixture was extracted with ethyl acetate (3×50 mL). The combined organic extracts were dried (Na2SO4), filtered and concentrated. The residue was purified by flash column chromatography (silica gel, 4:1 EtOAc/acetone) to afford 0.7 g (87%) of (R)-4-butylpyrrolidin-2-one as a colorless oil: [α]D=+0.95o (c=0.60, CH2Cl2) {lit. [α]D=−0.67o (c=0.60, CH2Cl2) for (S)-enantiomer, Meyers, A. I. and Snyder, L. 1993, J. Org. Chem 58, 36-42}; 1H NMR (CDCl3) δ 6.07 (bs, 1 H), 3.48 (t, 1 H), 3.02 (t, 1 H), 2.45 (m, 2 H), 1.99 (m, 1 H), 1.22-1.50 (m, 6 H), 0.90 (t, 3 H). MS(ES) m/e 142 [M+H]+.
    • 1(d) (R)-1-(5-Benzyloxypentyl)-4-butylpyrrolidin-2-one
  • To a solution of (R)-4-butylpyrrolidin-2-one (0.42 g, 2.9 mmol) in dry dimethylformamide (10 mL) under argon was slowly added sodium hydride (60% in mineral oil, 0.14 g, 3.5 mmol) at 0° C. After stirring at 0° C. for 30 minutes, 5-benzyloxypentyl bromide (0.9 g, 3.5 mmol) was added dropwise. The resulting mixture was stirred at room temperature overnight and then diluted with ethyl acetate (50 mL). The organic solution was washed with water (4×30 mL) and brine (30 mL), dried (Na2SO4) and concentrated. The residue was purified by flash column chromatography (silica gel, 1:1 EtOAc/hexanes) to afford 0.73 g (95%) of (R)-1-(5-benzyloxypentyl)-4-butylpyrrolidin-2-one as a colorless oil: 1H NMR (CDCl3) δ 7.33 (m, 5 H), 4.51 (s, 2 H), 3.45 (m, 3 H), 3.27 (t, 2 H), 2.99 (dd, 1 H), 2.32 (m, 1 H), 2.06 (m, 1 H), 1.24-1.71 (m, 12 H), 0.93 (t, 3 H). MS(ES) m/e 318 [M+H]+.
    • 1(e) [(3S,4R)-3-(Benzyloxyaminomethyl)-1-(5-benzyloxypentyl)-4-butyl-pyrrolidin-2-one
  • A solution of (R)-1-(5-benzyloxypentyl)-4-butylpyrrolidin-2-one (0.25 g, 0.79 mmol) in dry THF (3 mL) was slowly added to a 2 M solution of lithium diisopropylamide (0.47 mL, 0.94 mmol) in THF (2 mL) at −78° C. under argon. The reaction mixture was stirred at the same temperature for 1 h. Isopropyl formate (0.047 mL, 0.94 mmol) was then added dropwise. The resulting mixture was stirred for 3 h and then quenched with saturated ammonium chloride (10 mL). The mixture was extracted with ethyl acetate (3×10 mL) and the combined organic extracts were dried (Na2SO4), filtered, and concentrated. The residue was dissolved in dry pyridine (5 mL), and treated with benzyloxyamine hydrochloride (0.13 g, 0.79 mmol) at room temperature for 2 h. After removing the solvent under reduced pressure, the residue was dissolved in acetic acid (5 mL) and treated with NaCNBH3 (0.22 g, 1.03 mmol) at room temperature for 2 h. The mixture was diluted with ethyl acetate (10 mL) and neutralized with 10% aqueous NaOH. The organic phase was separated, washed with brine, dried (Na2SO4), and concentrated. The residue was purified by HPLC to give 0.11 g (31%) of [(3S,4R)-3-benzyloxyaminomethyl)-1-(5-benzyloxypentyl)-4-butyl-pyrrolidin-2-one as a colorless oil: 1H NMR (CDCl3) δ 7.32 (m, 10 H), 6.45 (bs, 1 H), 4.72 (s, 2 H), 4.51 (s, 2 H), 3.47 (t, 2 H), 3.39 (t, 1 H), 3.06-3.33 (m, 4 H), 2.93 (t, 1 H), 2.43 (m, 1H), 2.03 (m, 1 H), 1.23-1.73 (m, 12 H), 0.93 (t, 3 H). MS(ES) m/e 453 [M+H]+.
    • 1(f) N-[(3S,4R)-4-Butyl-1-(5-hydroxypentyl)-2-oxopyrrolidin-3-yl-methyl]-N-hydroxyformamide
  • A mixture of formic acid (0.011 mL, 0.29 mmol) and acetic anhydride (0.026 mL, 0.28 mmol) was heated to 50° C. for 1 h. To this mixture at room temperature was added a mixture of [(3S,4R)-3-(benzyloxyaminomethyl)-1-(5-benzyloxypentyl)-4-butyl-pyrrolidin-2-one (65 mg, 0.14 mmol) and triethylamine (0.02 mL, 0.18 mmol) in methylene chloride (3 mL). The resulting mixture was stirred at room temperature for 30 minutes. The reaction was diluted with methylene chloride (5 mL) and quenched with water (5 mL). The organic phase was washed with brine (5 mL), dried (Na2SO4), filtered, and concentrated. The residue was dissolved in methanol (3 mL) and stirred under a hydrogen balloon in the presence of palladium on activated carbon (40 mg) for 4 h. The reaction mixture was filtered, concentrated, and the residue was purified by HPLC to afford 25 mg (58%) of N-[(3S,4R)-4-butyl-1-(5-hydroxypentyl)-2-oxopyrrolidin-3-yl-methyl]-N-hydroxyformamide as a colorless glass: 1H NMR (CD3OD) δ 8.33 (s, 0.5 H), 7.98 (s, 0.5 H), 3.80 (m, 1 H), 3.57 (m, 3 H), 3.3 (m, 3 H), 3.07 (t, 1H), 2.55 (m, 1 H), 2.12-2.26 (m, 1H), 1.33-1.71 (m, 12 H), 0.94 (t, 3 H). MS(ES) m/e 301 [M+H]+.
    • EXAMPLE 2 Preparation of N-[(3R,4S)-4-Butyl-1-(5-hydroxypentyl)-2-oxopyrrolidin-3-yl-methyl]-N-hydroxyformamide
  • Following the procedure of Example 1(a)-1(f), except substituting (R)-1-(5-benzyloxypentyl)4-butylpyrrolidin-2-one with (S)-1-(5-benzyloxypentyl)-4-butylpyrrolidin-2-one, the title compound was prepared. It has the identical 1H NMR and MS as the compound of Example 1(f).
    • EXAMPLE 3 Preparation of (±)-(3RS,4SR)—N-(1-Benzyl-4-butyl-2-oxopyrrolidin-3-yl-methyl)-N-hydroxyformamide 3(a) 4-Butylpyrrolidin-2-one
  • To a solution of 3-nitromethylheptanoic acid ethyl ester (10 g, 49.2 mmol) in methanol (100 mL) under argon was added Raney Ni (5 g). The mixture was stirred under 50 psi of hydrogen for 48 h, flushed with argon, filtered through a Celite pad, and concentrated under vacuum to afford 4-butylpyrrolidin-2-one as a colorless oil (6.3 g, 91%). MS(ES) m/e 142 [M+H]+.
    • 3(b) (±)-(3RS,4SR)—N-(1-Benzyl-4-butyl-2-oxopyrrolidin-3-yl-methyl)-N-hydroxyformamide
  • Following the procedure of Example 1(d)-1(f), except substituting compound (R)-4-butylpyrrolidin-2-one with 4-butylpyrrolidin-2-one, and substituting 5-benzyloxypentyl bromide with benzyl bromide, (±)-(3RS,4SR)—N-(1-benzyl-4-butyl-2-oxopyrrolidin-3-ylmethyl)-N-hydroxyformamide was prepared as a colorless oil. MS(ES) m/e 305 [M+H]+.
  • Proceeding in a similar manner, except substituting appropriate intermediates for the benzyl bromide above, the following compounds were synthesized:
    • (±)-(3RS,4SR)—N-(4-Butyl-2-oxo-1-pyridin-3-ylmethylpyrrolidin-3-yl-methyl)-N-hydroxyformamide. MS(ES) m/e 306 [M+H]+.
    • (±)-(3RS,4SR)—N-[4-Butyl-1-(4-ethoxybenzyl)-2-oxopyrrolidin-3-yl-methyl]-N-hydroxyformamide. MS(ES) m/e 349 [M+H]+.
    • (±)-(3RS,4SR)—N-[4-Butyl-1-(2,3-dichlorobenzyl)-2-oxopyrrolidin-3-yl-methyl]-N-hydroxyformamide. MS(ES) m/e 373 [M+H]+.
    • (±)-(3RS,4SR)—N-[4-Butyl-1-(3,4-dichlorobenzyl)-2-oxo-pyrrolidin-3-yl-methyl]-N-hydroxyformamide. MS(ES) m/e 373 [M+H]+.
    • (±)-(3RS,4SR)—N-[4-Butyl-1-(3,5-dimethylisoxazol-4-yl-methyl)-2-oxopyrrolidin-3-yl-methyl]-N-hydroxyformamide. MS(ES) m/e 324 [M+H]+.
    • (±)-(3RS,4SR)—N-[4-Butyl-1-(2-methylthiazol-4-yl-methyl)-2-oxopyrrolidin-3-yl-methyl]-N-hydroxyformamide. MS(ES) m/e 326 [M+H]+.
    EXAMPLE 4 Preparation of (±)-(3RS,4SR)—N-[4-Butyl-1-(4-hydroxybenzyl)-2-oxopyrrolidin-3-yl-methyl]-N-hydroxyformamide 4(a) (±)-(3RS,4SR)—N-[1-(4-Allyloxybenzyl)-4-butyl-2-oxopyrrolidin-3-yl-methyl]-N-benzyloxyformamide
  • Following the procedure of Example 1(d)-1(f), except substituting compound (R)-4-butylpyrrolidin-2-one with the compound of Example of 3(a), and 5-benzyloxypentyl bromide with 4-allyloxybenzyl bromide, (±)-(3RS,4SR)—N-[1-(4-allyloxybenzyl)-4-butyl-2-oxopyrrolidin-3-yl-methyl]-N-benzyloxyformamide was prepared as a colorless oil. MS(ES) m/e 451 [M+H]+.
    • 4(b) (±)-(3RS,4SR)—N-Benzyloxy-N-[4-butyl-1-(4-hydroxybenzyl)-2-oxopyrrolidin-3-yl-methyl]formamide
  • To a solution of (±)-(3RS,4SR)—N-[1-(4-allyloxybenzyl)-4-butyl-2-oxopyrrolidin-3-yl-methyl]-N-benzyloxyformamide (2.6 g, 5.77 mmol) in dichloromethane (60 mL) under argon was added morpholine (6 mL), water (1.2 mL) and then tetrakis(triphenylphosphine)palladium (0.33 g, 0.28 mmol). The reaction mixture was stirred at rt for 1 h, filtered through a Celite pad and concentrated. The residue was purified by flash column chromatography (silica gel, ethyl acetate/hexanes 4:1) to afford (±)-(3RS,4SR)—N-benzyloxy-N-[4-butyl-1-(4-hydroxybenzyl)-2-oxopyrrolidin-3-yl-methyl]formamide as a white solid (2.1 g, 88%). MS(ES) m/e 411 [M+H]+.
    • 4(c) (±)-(3RS,4SR)—N-[4-Butyl-1-(4-hydroxybenzyl)-2-oxopyrrolidin-3-yl-methyl]-N-hydroxyformamide
  • (±)-(3RS,4SR)—N-Benzyloxy-N-[4-butyl-1-(4-hydroxybenzyl)-2-oxopyrrolidin-3-ylmethyl]formamide (0.13 g, 0.32 mmol) was dissolved in methanol (5 mL) and stirred under a hydrogen balloon in the presence of palladium on activated carbon (30 mg) for 4 h. The reaction mixture was filtered, concentrated and the residue was purified by HPLC to afford the title compound as a white solid (0.071 g, 70%). MS(ES) m/e 321 [M+H]+.
    • EXAMPLE 5 Preparation of (±)-(3RS,4SR)—N-[4-Butyl-1-[4-(furan-2-ylmethoxy)benzyl]-2-oxopyrrolidin-3-yl-methyl}-N-hydroxyformamide 5(a) (±) -(3RS,4SR)—N-Benzyloxy-N-{4-butyl-1-[4-(furan-2-ylmethoxy)benzyl]-2-oxo-pyrrolidin-3-yl-methyl}formamide
  • To a solution of (±)-(3RS,4SR)—N-benzyloxy-N-[4-butyl-1-(4-hydroxybenzyl)-2-oxopyrrolidin-3-yl-methyl]formamide (0.1 g, 0.24 mmol) in tetrahydrofuran (3 mL) under argon was added furan-2-yl-methanol (0.041 mL, 0.048 mmol) and triphenylphosphine (0.07 g, 0.27 mmol). The solution was cooled to 0° C. and diethyl azodicarboxylate (0.042 mL, 0.27 mmol) was added dropwise. The reaction mixture was warmed up to rt and stirred overnight. The reaction was quenched with saturated aqueous NaHCO3 (10 mL) and extracted with dichloromethane (3×10 mL). The combined extractions were dried (Na2SO4), filtered and concentrated. The residue was purified by flash column chromatography (silica gel, ethyl acetate/hexanes 1:1) to afford (±)-(3RS,4SR)—N-benzyloxy-N-{4-butyl-1-[4-(furan-2-yl-methoxy)benzyl]-2-oxopyrrolidin-3-yl-methyl}formamide as a colorless oil (0.075 g, 63%). MS(ES) m/e 491 [M+H]+.
    • 5(b) (±)-(3RS,4SR)—N-{4-Butyl-1-[4-(furan-2-yl-methoxy)benzyl]-2oxopyrrolidin-3-yl-methyl}-N-hydroxyformamide
  • Following the procedure of Example 4(c), (±)-(3RS,4SR)—N-{4-butyl-1-[4-(furan-2-yl-methoxy)benzyl]-2-oxopyrrolidin-3-yl-methyl}-N-hydroxyformamide was prepared as a colorless glass. MS(ES) m/e 401 [M+H]+.
  • Proceeding in a similar manner, but substituting appropriate intermediates for the furan-2-yl-methanol, the following compounds were synthesized:
    • (±)-(3RS,4SR)—N-{4-Butyl-1-[4-(2-morpholin-4-yl-2-oxoethoxy)benzyl]-2-oxopyrrolidin-3-yl-methyl]-N-hydroxyformamide. MS(ES) m/e 448 [M+H]+.
    • (±)-(3RS,4SR)—N-{4-Butyl-1-[4-(4-carboxy-1-butoxy)benzyl]-2-oxopyrrolidin-3-yl-methyl}-N-hydroxyformamide. MS(ES) m/e 407 [M+H]+.
    • (±)-(3RS,4SR)—N-{4-Butyl-1-[4-(3-hydroxybenzoxy)benzyl]-2-oxopyrrolidin-3-yl-methyl}-N-hydroxyformamide. MS(ES) m/e 427 [M+H]+.
    • (±)-(3RS,4SR)—N-{4-Butyl-2-oxo-1-[4-(tetrahydrofuran-2-ylmethoxy)benzyl]pyrrolidin-3-yl-methyl}-N-hydroxyformamide. MS(ES) m/e 405 [M+H]+.
    • (±)-(3RS,4SR)—N-{4-Butyl-1-[4-(3-hydroxypropoxy)benzyl]-2-oxo-yrrolidin-3-yl-methyl}-N-hydroxyformamide. MS(ES) m/e 379 [M+H]+.
    • (±)-(3RS,4SR)—N-{4-Butyl-2-oxo-1-[4-(piperidin-3-ylmethoxy)-benzyl]pyrrolidin-3-yl-methyl}-N-hydroxyformamide. MS(ES) m/e 418 [M+H]+.
    • (±)-(3RS,4SR)—N-{4-Butyl-2-oxo-1-[4-(pyridin-3-ylmethoxy)benzyl]pyrrolidin-3-yl-methyl}-N-hydroxyformamide. MS(ES) m/e 412 [M+H]+.
    • (±)-(3RS,4SR)—N-{4-Butyl-1-[4-(5-hydroxypentoxy)benzyl]-2-oxopyrrolidin-3-yl-methyl}-N-hydroxyformamide. MS(ES) m/e 407 [M+H]+.
    EXAMPLE 6 Preparation of (±)-(3RS,4SR)—N-(4-Butyl-2-oxo-1-phenylpyrrolidin-3-yl-methyl)-N-hydroxyformamide 6(a) 3-Hydroxymethyl-heptanoic acid phenylamide
  • To a solution of aniline (0.36 mL, 4.0 mmol) in toluene (10 mL) was added trimethylaluminum in toluene (2M, 2.5 mL, 5 mmol). After 20 min, a solution of (±)4-butyldihydrofuran-2-one (0.4 g, 4 mmol) in toluene (1 mL) was added and the reaction mixture was refluxed for 3 h. The reaction was cooled to 0° C. and carefully quenched with 1 M HCl (15 mL), and then extracted with dichloromethane (3×15 mL). The combined extractions were dried over Na2SO4, filtered and concentrated. The residue was purified by flash column chromatography (silica gel, ethyl acetate/hexanes 3:2) to afford 3-hydroxymethylheptanoic acid phenylamide as a white solid (0.66 g, 70%). MS(ES) m/e 236 [M+H]+.
    • 6(b) 4-Butyl-1-phenylpyrrolidin-2-one
  • To a solution of 3-hydroxymethylheptanoic acid phenylamide (0.61 g, 2.6 mmol) in THF (30 mL) under argon was added triphenylphosphine (1.36 g, 5.2 mmol). The solution was cooled to 0° C. and diethyl azodicarboxylate (0.61 mL, 3.9 mmol) was added dropwise. The reaction mixture was warmed up to rt and stirred overnight. The reaction was quenched with saturated aqueous NaHCO3 (50 mL) and extracted with dichloromethane (3×50 mL). The combined extractions were dried (Na2SO4), filtered and concentrated. The residue was purified by flash column chromatography (silica gel, ethyl acetate/hexanes 1:2) to afford 4-butyl-1-phenylpyrrolidin-2-one as a white solid (0.4 g, 72%). MS(ES) m/e 218 [M+H]+.
    • 6(c) (±)-(3RS,4SR)—N-(4-Butyl-2-oxo-1-phenylpyrrolidin-3-yl-methyl)-N-hydroxyformamide
  • Following the procedure of Example 1(e)-1(f), (±)-(3RS,4SR)—N-(4-butyl-2-oxo-1-phenylpyrrolidin-3-yl-methyl)-N-hydroxyformamide was prepared as a colorless glass. MS(ES) m/e 291 [M+H]+.
    • EXAMPLE 7 Preparation of (±)-(3RS,4SR)—N-[4-Butyl-2-oxo-1-(t-butylcarboxy)pyrrolidin-3-yl-methyl]-N-hydroxyformamide 7(a) 4-Butyl-2-oxopyrrolidine-1-carboxylic acid tert-butyl ester
  • To a solution of 4-butylpyrrolidin-2-one (4.1 g, 29.0 mmol) in dry acetonitrile (45 mL) was added triethylamine (6.1 mL, 43.6 mmol), di-tert-butyl dicarbonate (7.6 g, 34.8 mmol) and then 4-dimethylaminopyridine (0.3 g, 2.5 mmol). The reaction was stirred at rt for 4 h. The solvent was removed under vacuum, and the residue was dissolved in ethyl acetate (50 mL) and washed with water (30 mL) and brine (30 mL), dried (Na2SO4), filtered and concentrated. The residue was purified by flash column chromatography (silica gel, ethyl acetate/hexanes 1:9) to afford 4-butyl-2-oxopyrrolidine-1-carboxylic acid tert-butyl ester as a white solid (5.2 g, 75%). MS(ES) m/e 242 [M+H]+.
    • 7(b) (±)-(3RS,4SR)-3-[(Benzyloxyformylamino)methyl]-4-butyl-2-oxopyrrolidin-1-carboxylic acid tert-butyl ester
  • Following the procedures of Example 1(e)-1(f), except omitting the final hydrogenation step, (±)-(3RS,4SR)-3-[(benzyloxyformylamino)methyl]-4-butyl-2-oxopyrrolidin-1-carboxylic acid tert-butyl ester was prepared as a colorless oil. MS(ES) m/e 405 [M+H]+.
    • 7(c) (±)-(3RS,4SR)—N-[4-Butyl-2-oxo-1-(t-butylcarboxy)pyrrolidin-3-yl-methyl]-N-hydroxyformamide;
  • Following the procedure of Example 4(c), the title compound was prepared as a colorless glass. MS(ES) m/e 315 [M+H]+.
    • EXAMPLE 8 Preparation of (±)-(3RS,4SR)—N-(4-Butyl-2-oxopyrrolidin-3-yl-methyl)-N-hydroxyformamide 8(a) (±)-(3RS,4SR)—N-Benzyloxy-N-(4-butyl-2-oxopyrrolidin-3-yl-methyl)formamide
  • (±)-(3RS,4SR)-3-[(Benzyloxyformylamino)methyl]-4-butyl-2-oxopyrrolidin 1 -carboxylic acid tert-butyl ester (1.7 g, 4.2 mmol) was dissolved in 5% TFA/1,2-dichloroethane (100 mL) and the reaction was stirred at rt for 3 h. The solvents were removed under vacuum, the residue was dissolved in dichloromethane and washed with saturated aq. NaHCO3. The organic solution was dried (Na2SO4), filtered and concentrated. The residue was purified by flash column chromatography (silica gel, ethyl acetate) to afford (±)-(3RS,4SR)—N-benzyloxy-N-(4-butyl-2-oxopyrrolidin-3-yl-methyl)formamide as a white solid (0.95 g, 74%). MS(ES) m/e 305 [M+H]+.
    • 8(b) (±)-(3RS,4SR)—N-(4-Butyl-2-oxopyrrolidin-3-yl-methyl)-N-hydroxyformamide
  • Following the procedure of Example 4(c), (±)-(3RS,4SR)—N-(4-butyl-2-oxopyrrolidin-3-yl-methyl)-N-hydroxyformamide was prepared as a colorless glass. MS(ES) m/e 215 [M+H]+.
    • EXAMPLE 9 Preparation of (±)-(3RS,4SR)—N-[4-Butyl-2-oxo-1-(1-phenylmethanoyl)pyrrolidin-3-yl-methyl]-N-hydroxyformamide 9(a) (±)-(3RS,4SR)—N-Benzyloxy-N-[4-butyl-2-oxo-1-(1-phenylmethanoyl)pyrrolidin-3-yl-methyl)formamide
  • To a solution of (±)-(3RS,4SR)—N-benzyloxy-N-(4-butyl-2-oxopyrrolidin-3-yl-methyl)formamide (0.18 g, 0.59 mmol) in dry THF (3 mL) at −78° C. under argon was added dropwise lithium bis(trimethylsilyl)amide in THF (1 M, 0.71 mL). After 20 min, benzoyl chloride (0.077 mL, 0.89 mmol) was added dropwise and stirring continued for 2 h. The reaction was warmed up to 0° C., quenched with saturated aq. NH4Cl (10 mL) and extracted with dichloromethane (3×10 mL). The combined organic solution was dried (Na2SO4), filtered and concentrated. The residue was purified by flash column chromatography (silica gel, ethyl acetate/hexanes 1:1) to afford (±)-(3RS,4SR)—N-benzyloxy-N-[4-butyl-2-oxo-1-(1-phenylmethanoyl)pyrrolidin-3-yl-methyl)formamide as a white solid (0.12 g, 50%). MS(ES) m/e 409 [M+H]+.
    • 9(b) (±)-(3RS,4SR)—N-[4-Butyl-2-oxo-1-(1-phenylmethanoyl)pyrrolidin-3-yl-methyl]-N-hydroxyformamide
  • Following the procedure of Example 4(c), (±)-(3RS,4SR)—N-[4-butyl-2-oxo-1-(1-phenylmethanoyl)pyrrolidin-3-yl-methyl]-N-hydroxyformamide was prepared as a colorless glass. MS(ES) m/e 319 [M+H]+.
  • Proceeding in a similar manner, but substituting appropriate intermediates for those listed above, the following compounds were synthesized:
    • (±)-(3RS,4SR)—N-(4-Butyl-2-oxo-1-pentanoylpyrrolidin-3-yl-methyl)-N-hydroxyformamide. MS(ES) m/e 299 [M+H]+.
    • (±)-(3RS,4SR)—N-[4-Butyl-2-oxo-1-(2-phenylethanoyl)pyrrolidin-3-yl-methyl]-N-hydroxyformamide. MS(ES) m/e 333 [M+H]+.
    • (±)-(3RS,4SR)—N-(1-Benzenesulfonyl-4-butyl-2-oxopyrrolidin-3-yl-methyl)-N-hydroxyformamide. MS(ES) m/e 355 [M+H]+.
    • (±)-(3RS,4SR)—N-[1-(Butane-1-sulfonyl)-4-butyl-2-oxopyrrolidin-3-yl-methyl]-N-hydroxyformamide. MS(ES) m/e 335 [M+H]+.
    • (±)-(3RS,4SR)—N-[4-Butyl-1-(naphthalen-2-yl-methanoyl)-2-oxopyrrolidin-3-yl-methyl]-N-hydroxyformamide. MS(ES) m/e 369 [M+H]+.
    • (±)-(3RS,4SR)—N-{4-Butyl-1-[1-(4-ethoxyphenyl)methanoyl]-2-oxopyrrolidin-3-yl-methyl}-N-hydroxyformamide. MS(ES) m/e 363 [M+H]+.
    • (±)-(3RS,4SR)—N-{4-Butyl-1-[1-(3-ethoxyphenyl)methanoyl]-2-oxopyrrolidin-3-yl-methyl}-N-hydroxyformamide. MS(ES) m/e 363 [M+H]+.
    • (±)-(3RS,4SR)—N-{4-Butyl-1-[1-(2-ethoxyphenyl)-methanoyl]-2-oxopyrrolidin-3-yl-methyl}-N-hydroxyformamide. MS(ES) m/e 363 [M+H]+.
    • (±)-(3RS,4SR)—N-{4-Butyl-1-[2-(2-hydroxyphenyl)-2-oxoethyl]-2-oxopyrrolidin-3-yl-methyl}-N-hydroxyformamide. MS(ES) m/e 349 [M+H]+.
    EXAMPLE 10 Preparation of N-((3S,4R)-4-Butyl-1-{(S)-1-[1-(dimethylamino)methanoyl]-3,3-dimethylbutyl}-2-oxopyrrolidin-3-yl-methyl)-N-hydroxyformamide 10(a) (3S,4R)-3-Benzyloxymethyl-4-butyldihydrofuran-2-one
  • (R)-3-Hydroxymethylheptanoic acid, (S)-1-phenylethylamide (8.4 g, 31.9 mmol) was dissolved in 1 M H2SO4/dioxane (1:1, 110 mL) and the resulting solution was refluxed overnight under argon. After cooling to rt, the reaction mixture was diluted with ethyl acetate/hexanes (1:3, 200 mL) and washed with water (2×100 mL), saturated aq. NaHCO3 (2 ×100 mL), and brine (100 mL). The solution was dried (Na2SO4), filtered, and concentrated to afford pure (R)-4-butyldihydrofuran-2-one as a colorless oil (3.5 g, 78%).
  • To a solution of diisopropylamine (1.28 mL, 9.1 mmol) in dry THF (15 mL) at 0° C. was dropwise added n-butyl lithium (1.6 M, 8.4 mmol). After 30 min, the solution was cooled to −78° C. and (R)-4-butyldihydrofuran-2-one (1.0 g, 7.0 mmol) was added slowly. The mixture was stirred for an additional 30 min. Trimethylsilyl chloride (1.78 mL, 14 mmol) was rapidly added and the mixture was gradually warmed up to rt during a period of 3 h. The reaction mixture was concentrated under vacuum, and hexanes (15 mL) was added to the residue. Rapid filtration and removal of the solvent under vacuum yielded crude t-butyl-[(R)-4-butyl-4,5-dihydrofuran-2-yloxy]silane as a colorless oil (1.32 g, 88%). This crude intermediate was dissolved in dry dichloromethane (20 mL) under argon. The solution was cooled to 0° C. and treated with benzyloxymethyl chloride (1.5 mL, 10 mmol) followed by zinc bromide (20 mg). The reaction was warmed up to rt and stirred overnight. Aqueous work-up and purification by flash column chromatography (silica gel, ethyl acetate/hexanes 1:6) afforded (3S,4R)-3-benzyloxymethyl-4-butyldihydrofuran-2-one as a colorless oil (1.1 g, 66%). MS(ES) m/e 263 [M+H]+.
    • 10(b) (2S,3R)-2-Benzyloxymethyl-3-hydroxymethylheptanoic acid [(S)-dimethylcarbamoyl-dimethylpropyl]amide
  • (3S,4R)-3-Benzyloxymethyl-4-butyldihydrofuran-2-one (0.2 g, 0.76 mmol), (S)-2-amino-3,3,N,N-tetramethylbutyramide (0.5 g, 3.16 mmol) and 2-hydroxypyridine (0.073 g, 0.76 mmol) were mixed in a sealed tube under argon and heated to 80° C. for 36 h. After cooling to rt, the reaction mixture was treated with 1 M HCl (20 ml) and extracted with ethyl acetate (4×30 mL). Removal of the solvent under vacuum and purification of the residue by HPLC afforded (2S,3R)-2-benzyloxymethyl-3-hydroxymethylheptanoic acid [(S)-dimethylcarbamoyl-dimethylpropyl]amide as a white solid (0.14 g, 44%). MS(ES) m/e 421 [M+H]+.
    • 10(c) (S)-2-[(3S,4R)-3-Benzyloxymethyl-4-butyl-2-oxopyrrolidin-1-yl]-3,3,N,N-tetramethyl butyramide
  • To a solution of (2S,3R)-2-benzyloxymethyl-3-hydroxymethylheptanoic acid [(S)-dimethylcarbamoyl-dimethylpropyl]amide (0.14 g, 0.33 mmol) in THF (2 mL) under argon was added a premixed solution of tributylphosphine (0.12 mL, 0.48 mmol) and di-t-butyl azodicarboxylate (0.11 g, 0.48 mmol) in THF (1 mL) at 0° C. The reaction was warmed up to rt and stirred overnight. Aqueous work-up and purification of the residue by HPLC afforded (S)-2-[(3S,4R)-3-benzyloxymethyl-4-butyl-2-oxopyrrolidin-1-yl]-3,3,N,N-tetramethyl butyramide as a white solid (0.08 g, 60%). MS(ES) m/e 403 [M+H]+.
    • 10(d) (S)-2-[(3S,4R)-3-Benzyloxyiminomethyl-4-butyl-2-oxopyrrolidin-1-yl]-3,3,N,N-tetramethyl butyramide
  • (S)-2-[(3S,4R)-3-Benzyloxymethyl-4-butyl-2-oxopyrrolidin-1-yl]-3,3,N,N-tetramethyl butyramide (0.08 g, 0.2 mmol) was dissolved in methanol (2 mL) and stirred overnight under a hydrogen balloon in the presense of palladium on activated carbon (15 mg). Filtration followed by concentration provided a crude alcohol (58 mg) which was dissolved in dichloromethane (5 mL) and treated with Dess-Martin periodinane (0.13 g, 0.3 mmol) at 0° C. After warming up to rt, the reaction was stirred overnight and the solvent was removed under vacuum. The residue was then dissolved in pyridine (5 mL) and benzyloxyamine hydrochloride (0.064 g, 0.4 mmol) was added. After 1 h, the reaction mixture was condensed to dryness, the residue was dissolved in 1 N aq. NaOH/dichloromethane (2:3, 15 mL). The organic phase was separated, the aqueous phase was extracted with dichloromethane (5 mL). The combined organic extracts were dried (Na2SO4), filtered and concentrated. Purification of the residue by HPLC afforded (S)-2-[(3S,4R)-3-benzyloxyiminomethyl-4-butyl-2-oxopyrrolidin-1-yl]-3,3,N,N-tetramethyl butyramide as a colorless oil (0.05 g, 61%). MS(ES) m/e 416 [M+H]+.
    • 10(e) N-((3S,4R)-4-Butyl-1-{(S)-1-[1-(dimethylamino)methanoyl]-3,3-dimethylbutyl}-2-oxopyrrolidin-3-yl-methyl)-N-hydroxyformamide
  • Following the procedures of 1(e)-1(f), beginning with the sodium cyanoborohydride reduction, N-((3S,4R)-4-Butyl-1-{(S)-1-[1-(dimethylamino)methanoyl]-3,3-dimethylbutyl}-2-oxopyrrolidin-3-yl-methyl)-N-hydroxyformamide was prepared as a colorless glass. MS(ES) m/e 356 [M+H]+.
  • Proceeding in a similar manner, but substituting appropriate intermediates for the ones listed above, the following compounds were synthesized:
    • N-((3S,4R)-4-Butyl-1-{(S)-1-[1-((S)-2-methoxymethyl-pyrrolidin-1-yl)-methanoyl]-3-methyl-butyl}-2-oxo-pyrrolidin-3-yl-methyl)-N-hydroxyformamide. MS(ES) m/e 426 [M+H]+.
    • N-((3R,4S)-4-Butyl-1-{(S)-1-[1-((S)-2-methoxymethyl-pyrrolidin-1-yl)-methanoyl]-3-methyl-butyl}-2-oxo-pyrrolidin-3-yl-methyl)-N-hydroxyformamide. MS(ES) m/e 426 [M+H]+.
    • With appropriate manipulation and protection of any chemical functionality, synthesis of the remaining compounds of Formula (1) is accomplished by methods analogous to those above and to those described in the Experimental section.
  • In order to use a compound of the Formula (1) or a pharmaceutically acceptable salt thereof for the treatment of humans and other mammals, it is normally formulated in accordance with standard pharmaceutical practice as a pharmaceutical composition.
  • The present compounds are useful for the treatment of bacterial infections including, but not limited to, respiratory tract infections and/or Gram positive infections.
  • Compounds of Formula (I) and their pharmaceutically acceptable salts may be administered in a standard manner for antibiotics, for example orally, parenterally, sub-lingually, dermally, transdermally, rectally, via inhalation or via buccal administration.
  • Compositions of Formula (I) and their pharmaceutically acceptable salts which are active when given orally can be formulated as syrups, tablets, capsules, creams and lozenges. A syrup formulation will generally consist of a suspension or solution of the compound or salt in a liquid carrier for example, ethanol, peanut oil, olive oil, glycerine or water with a flavoring or coloring agent. Where the composition is in the form of a tablet, any pharmaceutical carrier routinely used for preparing solid formulations may be used. Examples of such carriers include magnesium stearate, terra alba, talc, gelatin, acacia, stearic acid, starch, lactose and sucrose. Where the composition is in the form of a capsule, any routine encapsulation is suitable, for example using the aforementioned carriers in a hard gelatin capsule shell. Where the composition is in the form of a soft gelatin shell capsule any pharmaceutical carrier routinely used for preparing dispersions or suspensions may be considered, for example aqueous gums, celluloses, silicates or oils, and are incorporated in a soft gelatin capsule shell.
  • Typical parenteral compositions consist of a solution or suspension of a compound or salt in a sterile aqueous or non-aqueous carrier optionally containing a parenterally acceptable oil, for example polyethylene glycol, polyvinylpyrrolidone, lecithin, arachis oil or sesame oil.
  • Typical compositions for inhalation are in the form of a solution, suspension or emulsion that may be administered as a dry powder or in the form of an aerosol using a conventional propellant such as dichlorodifluoromethane or trichlorofluoromethane.
  • A typical suppository formulation comprises a compound of Formula (I) or a pharmaceutically acceptable salt thereof which is active when administered in this way, with a binding and/or lubricating agent, for example polymeric glycols, gelatins, cocoa-butter or other low melting vegetable waxes or fats or their synthetic analogs.
  • Typical dermal and transdermal formulations comprise a conventional aqueous or non-aqueous vehicle, for example a cream, ointment, lotion or paste or are in the form of a medicated plaster, patch or membrane.
  • Preferably the composition is in unit dosage form, for example a tablet, capsule or metered aerosol dose, so that the patient may administer a single dose.
  • Each dosage unit for oral administration contains suitably from 0.1 mg to 500 mg/Kg, and preferably from 1 mg to 100 mg/Kg, and each dosage unit for parenteral administration contains suitably from 0.1 mg to 100 mg/Kg, of a compound of Formula(I) or a pharmaceutically acceptable salt thereof calculated as the free acid. Each dosage unit for intranasal administration contains suitably 1-400 mg and preferably 10 to 200 mg per person. A topical formulation contains suitably 0.01 to 5.0% of a compound of Formula (1).
  • The daily dosage regimen for oral administration is suitably about 0.01 mg/Kg to 40 mg/Kg, of a compound of Formula(I) or a pharmaceutically acceptable salt thereof calculated as the free acid. The daily dosage regimen for parenteral administration is suitably about 0.001 mg/Kg to 40 mg/Kg, of a compound of Formula (I) or a pharmaceutically acceptable salt thereof calculated as the free acid. The daily dosage regimen for intranasal administration and oral inhalation is suitably about 10 to about 500 mg/person. The active ingredient may be administered from 1 to 6 times a day, sufficient to exhibit the desired activity.
  • No unacceptable toxicological effects are expected when compounds of the present invention are administered in accordance with the present invention.
  • The biological activity of the compounds of Formula (I) are demonstrated by the following test:
  • Biological Assay:
  • S. aureus or E. coli PDF activity is measured at 25° C., using a continuous enzyme-linked assay developed by Lazennec & Meinnel, (1997) “Formate dehydrogenase-coupled spectrophotometric assay of peptide deformylase” Anal. Biochem 244, pp. 180-182, with minor modifications. The reaction mixture is contained in 50 uL with 50 mM potassium phosphate buffer (pH7.6), 15 mM NAD, 0.25 U formate dehydrogenase. The substrate peptide, f-Met-Ala-Ser, is included at the KM concentration. The reaction is triggered with the addition of 10 nM Def1 enzyme, and absorbance is monitored for 20 min at 340 nm.
  • Antimicrobial Activity Assay
  • Whole-cell antimicrobial activity was determined by broth microdilution using the National Committee for Clinical Laboratory Standards (NCCLS) recommended procedure, Document M7-A4, “Methods for Dilution Susceptibility Tests for Bacteria that Grow Aerobically” (incorporated by reference herein). The compound was tested in serial two-fold dilutions ranging from 0.06 to 64 mcg/ml. A panel of 12 strains were evaluated in the assay. This panel consisted of the following laboratory strains: Staphylococcus aureus Oxford, Staphylococcus aureus WCUH29, Enterococcus faecalis I, Enterococcus faecalis 7, Haemophilus influenzae Q1, Haemophilus influenzae NEMC1, Moraxella catarrhalis 1502, Streptococcus pneumoniae 1629, Streptococcus pneumoniae N1387, Streptococcus pneumoniae N1387, E. coli 7623 (AcrABEFD+) and E. coli 120 (AcrAB−). The minimum inhibitory concentration (MIC) was determined as the lowest concentration of compound that inhibited visible growth. A mirror reader was used to assist in determining the MIC endpoint.
  • All publications, including but not limited to patents and patent applications, cited in this specification are herein incorporated by reference as if each individual publication were specifically and individually indicated to be incorporated by reference herein as though fully set forth.
  • The above description fully discloses the invention including preferred embodiments thereof. Modifications and improvements of the embodiments specifically disclosed herein are within the scope of the following claims. Without further elaboration, it is believed that one skilled in the area can, using the preceding description, utilize the present invention to its fullest extent. Therefore the Examples herein are to be construed as merely illustrative and not a limitation of the scope of the present invention in any way. The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows.

Claims (4)

1. A compound according to formula (I):
Figure US20060025412A1-20060202-C00024
wherein:
R1 is selected from the group consisting of C1-6alkyl, —C1-2alkylAr, and Ar;
R2 is selected from the group consisting of hydrogen, C1-6alkyl, —(CH2)mOH, —(CH2)nAr′, —(CH2)nHet, —Ar′, —SO2R3, —C(O)R3, —C(O)NHR3, —C(O)OR3, —CH(R4)CONR5R6, and —CH(R4)CO2R7;
R3 is selected from the group consisting of C1-6alkyl, —C1-2alkylAr′, and Ar′;
R4 is hydrogen, or C1-6alkyl;
R5 and R6 are independently selected from the group consisting of hydrogen, C1-6alkyl,
—C1-2alkylAr′, and Ar′; or R5, R6 together form a five or six membered cycloalkyl ring which is optionally mono-substituted by —CH2OR7;
R7 is selected from the group consisting of hydrogen, and C1-3alkyl;
Ar is selected from the group consisting of phenyl, furyl, and thienyl, all of which may be optionally substituted by one or more Z1 groups;
Ar′ is selected from the group consisting of phenyl, naphthyl, furyl, pyridyl, thienyl, thiazolyl, isothiazolyl, pyrazolyl, triazolyl, tetrazolyl, imidazolyl, imidazolidinyl, benzofuranyl, indolyl, thiazolidinyl, isoxazolyl, oxadiazolyl, thiadiazolyl, morpholinyl, piperidinyl, piperazinyl, pyrrolyl, and pyrimidyl, all of which may be optionally substituted by one or more Z2 groups;
Het is selected from the group consisting of tetrahydrofuranyl and piperidinyl;
Z1 is independently selected from the group consisting of hydrogen, C1-3alkyl, —CN, F, Cl, Br, and I;
Z2 is independently selected from the group consisting of hydrogen, C1-6alkyl, C1-6alkoxy, —(CH2)nCO2R4, —C(O)NR5R6, —CN, —(CH2)nOH, —NO2, F, Cl, Br, I, —NR5R6, and —NHC(O)R1;
m is 2 to 5; and
n is 0 to 5; or a pharmaceutically acceptable salt thereof.
2. A compound according to claim 1 selected from the group consisting of:
N-[(3S,4R)-4-Butyl-1-(5-hydroxypentyl)-2-oxopyrrolidin-3-yl-methyl]-N-hydroxyformamide;
N-[(3R,4S)-4-Butyl-1-(5-hydroxypentyl)-2-oxopyrrolidin-3-yl-methyl]-N-hydroxyformamide;
(±)-(3RS,4SR)—N-[4-Butyl-2-oxo-1-(t-butylcarboxy)pyrrolidin-3-yl-methyl]-N-hydroxyformamide;
(±)-(3RS,4SR)—N-(4-Butyl-2-oxopyrrolidin-3-yl-methyl)-N-hydroxyformamide;
(±)-(3RS,4SR)—N-(4-Butyl-2-oxo-1-pentanoylpyrrolidin-3-yl-methyl)-N-hydroxyformamide;
(±)-(3RS,4SR)—N-[4-Butyl-2-oxo-1-(2-phenylethanoyl)pyrrolidin-3-yl-methyl]-N-hydroxyformamide;
(±)-(3RS,4SR)—N-[4-Butyl-2-oxo-1-(1-phenylmethanoyl)pyrrolidin-3-yl-methyl]-N-hydroxyformamide;
(±)-(3RS,4SR)—N-(1-Benzenesulfonyl-4-butyl-2-oxopyrrolidin-3-yl-methyl)-N-hydroxyformamide;
(±)-(3RS,4SR)—N-[1-(Butane-1-sulfonyl)-4-butyl-2-oxopyrrolidin-3-yl-methyl]-N-hydroxyformamide;
(±)-(3RS,4SR)—N-[4-Butyl-1-(naphthalen-2-ylmethanoyl)-2-oxopyrrolidin-3-yl-methyl]-N-hydroxyformamide;
(±)-(3RS,4SR)—N-(1-Benzyl-4-butyl-2-oxopyrrolidin-3-yl-methyl)-N-hydroxyformamide;
(±)-(3RS,4SR)—N-{4-Butyl-1-[1-(4-ethoxyphenyl)methanoyl]-2-oxopyrrolidin-3-yl-methyl}-N-hydroxyformamide;
(±)-(3RS,4SR)—N-{4-Butyl-1-[1-(3-ethoxyphenyl)methanoyl]-2-oxopyrrolidin-3-yl-methyl}-N-hydroxyformamide;
(±)-(3RS,4SR)—N-{4-Butyl-1-[1-(2-ethoxyphenyl)methanoyl]-2-oxopyrrolidin-3-yl-methyl}-N-hydroxyformamide;
(±)-(3RS,4SR)—N-(4-Butyl-2-oxo-1-pyridin-3-ylmethylpyrrolidin-3-yl-methyl)-N-hydroxyformamide;
N-((3S,4R)-4-Butyl-1-{(S)-1-[1-((S)-2-methoxymethyl-pyrrolidin-1-yl)methanoyl]-3-methylbutyl}-2-oxopyrrolidin-3-yl-methyl)-N-hydroxyformamide;
N-((3R,4S)-4-Butyl-1-{(S)-1-[1-((S)2-methoxymethylpyrrolidin-1-yl)-methanoyl]-3-methylbutyl}-2-oxopyrrolidin-3-yl-methyl)-N-hydroxyformamide;
N-((3S,4R)-4-Butyl-1-{(S)-1-[1-(dimethylamino)methanoyl]-3,3-dimethylbutyl}-2-oxopyrrolidin-3-yl-methyl)-N-hydroxyformamide;
(±)-(3RS,4SR)—N-[4-Butyl-1-(4-ethoxybenzyl)-2-oxopyrrolidin-3-yl-methyl]-N-hydroxyformamide;
(±)-(3RS,4SR)—N-[4-Butyl-1-(4-hydroxybenzyl)-2-oxopyrrolidin-3-yl-methyl]-N-hydroxyformamide;
(±)-(3RS,4SR)—N-{4-Butyl-1-[4-(2-morpholin-4-yl-2-oxoethoxy)benzyl]-2-oxopyrrolidin-3-yl-methyl}-N-hydroxyformamide;
(±)-(3RS,4SR)—N-{4-Butyl-1-[4-(4-carboxy-1-butoxy)benzyl]-2-oxopyrrolidin-3-yl-methyl}-N-hydroxyformamide;
(±)-(3RS,4SR)—N-{4-Butyl-1-[4-(3-hydroxybenzoxy)benzyl]-2-oxopyrrolidin-3-yl-methyl}-N-hydroxyformamide;
(±)-(3RS,4SR)—N-{4-Butyl-2-oxo-1-[4-(tetrahydrofuran-2-ylmethoxy)benzyl]pyrrolidin-3-yl-methyl}-N-hydroxyformamide;
(±)-(3RS,4SR)—N-{4-Butyl-1-[4-(furan-2-ylmethoxy)benzyl]-2-oxopyrrolidin-3-yl-methyl}-N-hydroxyformamide;
(±)-(3RS,4SR)—N-{4-Butyl-1-[4-(3-hydroxypropoxy)benzyl]-2-oxopyrrolidin-3-yl-methyl}-N-hydroxyformamide;
(±)-(3RS,4SR)—N-{4-Butyl-2-oxo-1-[4-(piperidin-3-ylmethoxy)benzyl]pyrrolidin-3-yl-methyl}-N-hydroxyformamide;
(±)-(3RS,4SR)—N-{4-Butyl-2-oxo-1-[4-(pyridin-3-ylmethoxy)benzyl]pyrrolidin-3-yl-methyl}-N-hydroxyformamide;
(±)-(3RS,4SR)—N-{4-Butyl-1-[4-(5-hydroxypentoxy)benzyl]-2-oxopyrrolidin-3-yl-methyl}-N-hydroxyformamide;
(±)-(3RS,4SR)—N-[4-Butyl-1-(2,3-dichlorobenzyl)-2-oxopyrrolidin-3-yl-methyl]-N-hydroxyformamide;
(±)-(3RS,4SR)—N-[4-Butyl-1-(3,4-dichlorobenzyl)-2-oxopyrrolidin-3-yl-methyl]-N-hydroxyformamide;
(±)-(3RS,4SR)—N-(4-Butyl-2-oxo-1-phenylpyrrolidin-3-yl-methyl]-N-hydroxyformamide;
(±)-(3RS,4SR)—N-{4-Butyl-1-[2-(2-hydroxyphenyl)-2-oxoethyl]-2-oxopyrrolidin-3-yl-methyl}-N-hydroxyformamide;
(±)-(3RS,4SR)—N-[4-Butyl-1-(3,5-dimethylisoxazol-4-ylmethyl)-2-oxopyrrolidin-3-yl-methyl]-N-hydroxyformamide; and
(±)-(3RS,4SR)—N-[4-Butyl-1-(2-methylthiazol-4-ylmethyl)-2-oxopyrrolidin-3-yl-methyl]-N-hydroxyformamide; or pharmaceutically acceptable salt thereof.
3. A method of treating a bacterial infection by administering to a subject in need of treatment a compound according to claim 1.
4. A pharmaceutical composition comprising a compound according to claim 1 and one or more pharmaceutically-acceptable excipients.
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Citations (1)

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Publication number Priority date Publication date Assignee Title
US6495548B1 (en) * 1999-04-02 2002-12-17 Bristol-Myers Squibb Pharma Company Lactam inhibitors of matrix metalloproteinases, TNF-α and aggrecanase

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6495548B1 (en) * 1999-04-02 2002-12-17 Bristol-Myers Squibb Pharma Company Lactam inhibitors of matrix metalloproteinases, TNF-α and aggrecanase

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