HK1026892B - Imidazole and imidazoline derivatives and uses thereof - Google Patents

Description

Background of The Invention

Throughout this application, various references are referred to within parentheses. Disclosure of these publications in their entireties are hereby incorporated by reference into this application to more fully describe the state of the art to which this invention pertains.

α-Adrenergic receptors (Lomasney, J.W. et al., Biochim. Biophy. Acta 1991, 1095, 127) are cell membrane proteins located in both the peripheral and central nervous systems. They belong to a diverse family of structurally related receptors which contain seven putative transmembrane helices and couple to intracellular guanine nucleotide binding proteins (G-proteins). These receptors are important switches for controlling many physiological functions and, thus, represent important targets for drug development. In fact, many α-adrenergic drugs have been developed over the past 40 years. Examples include clonidine, phenoxybenzamine and prazosin (for treatment of hypertension), naphazoline (for nasal decongestion), medetomidine (for veterinary analgesia), UK-14,304 and apraclonidine (for glaucoma). α-Adrenergic drugs can be divided into two distinct classes: agonists (like clonidine and naphazoline) which mimic the receptor activation properties of the endogenous neurotransmitter norepinephrine, and antagonists (like phenoxybenzamine and prazosin) which act to block the effects of norepinephrine. However, many of these drugs, though effective, also produce undesirable side effects. For example, clonidine produces dry mouth and sedation in addition to its antihypertensive effects.

Prior to 1977, only one α-adrenergic receptor was known to exist. Between 1977 and 1988, it was accepted by the scientific community that at least two α-adrenergic receptors α₁ and α₂ existed. Since 1988, new techniques in molecular biology have led to the identification of at least six α-adrenergic receptors - α_1a , α_1b , α_1c , α_2a , α_2b and α_2c (Bylund, D.B., FASEB J. 1992, 6, 832). In addition, current α₂-adrenergic drugs are not selective for any particular α₂-adrenergic receptor subtype. This lack of selectivity likely contributes to the untoward side effects of these drugs.

α₂ receptors are located both presynaptically at nerve terminals and postsynaptically as in vascular smooth muscles, platelets, pancreatic β-cells, and fat cells. Activation of the presynaptic receptors inhibit the release of norepinephrine by a negative feedback mechanism. Blockade of these receptors would therefore increase the release of norepinephrine.

It is believed that α₂ receptors can modulate pain. Indeed, the effects of α₂ agonists on analgesia, anesthesia and sedation have been well documented (Pertovaara, A., Progress in Neurobiology, 1993, 40, 691). For example, systemic administration of clonidine has been shown to produce antinociception in various species including human patients in addition to its well known sedative effects. Intrathecal and epidural administration of clonidine has also proved effective in producing analgesia. Another agonist, medetomidine, which has better α₂/α₁ selectivity and is more potent at α₂ receptors than clonidine, has been shown in humans to be effective for ischemic pain even though the doses were high enough to produce sedation and considerable decrease in blood pressure.

However, in anesthetic practice, the sedative effect of α₂ agonists is regarded as a good component of premedication. Another beneficial effect of α₂ agonists is their ability to potentiate the anesthetic action and hence to reduce the anesthetic requirements of other agents during surgery (Ghingnone, M. et al., Anesthesiology 1986, 64, 36).

Other potential uses of α₂ agonists include lowering intraocular pressure, treating hypertension, alcohol and drug withdrawal, rheumatoid arthritis, ischemia, migraine, cognitive deficiency, spasticity, diarrhea and nasal congestion (Cossement, E. et al., United States Patent 4923665, 1990).

This invention is directed to imidazole and imidazoline compounds which are selective agonists for human α₂ receptors. This invention is also related to the use of these compounds for treating disorders involving inhibition or lack of activation of α₂ adrenergic receptors such as hypertension, pain, glaucoma, alcohol and drug withdrawal, rheumatoid arthritis, ischemia, migraine, cognitive deficiency, spasticity, diarrhea and nasal congestion.

Summary of The Invention

This invention is directed to imidazole and imidazoline compounds which are selective agonists for human α₂ receptors. This invention is also related to the use of these compounds for treating disorders involving inhibition or lack of activation of α₂ adrenergic receptors such as hypertension, pain, glaucoma, alcohol and drug withdrawal, rheumatoid arthritis, ischemia, migraine, cognitive deficiency, spasticity, diarrhea and nasal congestion. The invention further provides a pharmaceutical composition comprising a therapeutically effective amount of the above-defined compounds and a pharmaceutically acceptable carrier.

The present invention also provides a compound having the structure: wherein each of Z1, Z2 and Z3 is N or CR₂, with the proviso that either one of Z1, Z2 or Z3 is N and the others of Z1, Z2 or Z3 are CR₂, or both Z1 and Z3 are N and Z2 is CR₂; wherein R₁ is H; F; straight chained or branched C₁ - C₄ alkyl, C₁ - C₄ monofluoroalkyl or C₁ - C₄ polyfluoroalkyl; straight chained or branched C₁ - C₄ alkoxy, -OH; or - (CH₂) qOH; wherein each R₂ is independently H; F; Cl; Br; I; -NO₂, -CN; straight chained or branched C₁ - C₄ alkyl; C₁ - C₄ monofluoroalkyl or C₁ - C₄ polyfluoroalkyl; straight chained or branched C₁ - C₄ alkoxy; -OH; - (CH₂) qOH; -COR₄; CO₂R₄; CONHR₄; phenyl; or benzyl; wherein each R₄ is independently H; straight chained or branched C₁-C₄ alkyl, C₁-C₄ monofluoroalkyl or C₁-C₄ polyfluoroalkyl; or phenyl; and wherein q is each independently 0, 1, 2 or 3; or a pharmaceutically acceptable salt thereof.

The present invention also provides a pharmaceutical composition comprising a therapeutically effective amount of the compounds described herein and a pharmaceutically acceptable carrier.

The present invention additionally provides for the use of a compound for the manufacture of a pharmaceutical composition for treating an α₂ adrenergic receptor associated disorder in a subject, whereby the compound is used in an amount effective to treat the disorder and whereby the compound has the structure: wherein each of Z1, Z2 and Z3 is N or CR₂, with the proviso that either one of Z1, Z2 or Z3 is N and the others of Z1, Z2 or Z3 are CR₂, or both Z1 and Z3 are N and Z2 is CR₂; wherein R₁ is H; F; straight chained or branched C₁ - C₄ alkyl, C₁ - C₄ monofluoroalkyl or C₁ - C₄ polyfluoroalkyl; straight chained or branched C₁ - C₄ alkoxy, -OH; or - (CH₂)_qOH; wherein each R₂ is Independently H; F; Cl; Br; I; -NO₂, -CN; straight chained or branched C₁ - C₄ alkyl; C₁ - C₄ monofluoroalkyl or C₁ - C₄ polyfluoroalkyl; straight chained or branched C₁ - C₄ alkoxy; -OH; - (CH₂) qOH; -COR₄; CO₂R₄; CONHR₄; phenyl; or benzyl; wherein each R₄ is independently H; straight chained or branched C₁ - C₄ alkyl, C₁ - C₄ monofluoroalkyl or C₁ - C₄ polyfluoroalkyl; or phenyl; and wherein q is each independently 0, 1, 2 or 3; or a pharmaceutically acceptable salt thereof.

The present invention additionally provides for the use of a compound for the manufacture of a pharmaceutical composition for treating pain in a subject, whereby the compound is used in an amount effective to treat the pain and whereby the compound has the structure: wherein each of Z1, Z2 and Z3 is N or CR₂, with the proviso that either one of Z1, Z2 or Z3 is N and the others of Z1, Z2 or Z3 are CR₂, or both Z1 and Z3 are N and Z2 is CR₂; wherein R₁ is H; F; straight chained or branched C₁ - C₄ alkyl, C₁ - C₄ monofluoroalkyl or C₁ - C₄ polyfluoroalkyl; straight chained or branched C₁ - C₄ alkoxy, -OH; or - (CH₂) qOH; wherein each R₂ is independently H; F; Cl; Br, I; -NO₂, -CN; straight chained or branched C₁ - C₄ alkyl; C₁ - C₄ monofluoroalkyl or C₁ - C₄ polyfluoroalkyl: straight chained or branched C₁ - C₄ alkoxy; -OH; - (CH₂) qOH; -COR₄; CO₂R₄; CONHR₄; phenyl; or benzyl; wherein each R₄ is independently H; straight chained or branched C₁ - C₄- alkyl, C₁ - C₄ monofluoroalkyl or C₁ - C₄ polyfluoroalkyl; or phenyl; and wherein q is each independently 0, 1, 2 or 3; or a pharmaceutically acceptable salt thereof.

Detailed Description of the Invention

The present invention is also directed to compounds having the structure: wherein each of Z1, Z2 and Z3 is N or CR₂, with the proviso that either one of Z1, Z2 or Z3 is N and the others of Z1, Z2 or Z3 are CR₂, or both Z1 and Z3 are N and Z2 is CR₂; wherein R₁ is H; F; straight chained or branched, C₁ - C₄ alkyl, C₁ - C₄ monofluoroalkyl or C₁ - C₄ polyfluoroalkyl; straight chained or branched C₁ - C₄ alkoxy, -OH; or - (CH₂) qOH; wherein each R₂ is independently H; F; Cl; Br, I; -NO₂, -CN; straight chained or branched C₁ - C₄ alkyl; C₁ - C₄ monofluoroalkyl or C₁ - C₄ polyfluoroalkyl; straight chained or branched C₁ - C₄ alkoxy; -OH; - (CH₂)_qOH; -COR₄; CO₂R₄; CONHR₄; phenyl; or benzyl; wherein each R₄ is independently H; straight chained or branched C₁ - C₄ alkyl, C₁ - C₄ monofluoroalkyl or C₁ - C₄ polyfluoroalkyl; or phenyl; and wherein q is each independently 0, 1, 2 or 3; or a pharmaceutically acceptable salt thereof.

Furthermore, the compounds of the present invention are preferably at least 80% pure, more preferably at least 90% pure, and most preferably at least 95% pure. The invention further provides for the (+) or (-) enantiomer of any of the compounds described herein such as a cis isomer or trans isomer.

The compounds of the present invention may be present as enantiomers, disteriomers or isomers, or as a racemic mixture.

In an additional embodiment of the present invention two of Z1,Z2 and Z3 are CH₂ and the other is N.

In an additional embodiment of the present invention at least one R₂ is methyl or phenyl. In yet another embodiment of the present invention R₁ is C₁-C₃ alkyl, C₁-C₃ alkoxy, or -OH.

In an embodiment of the present invention the compound has the structure:

The present invention also provides a pharmaceutical composition comprising a therapeutically effective amount of the compounds described herein and a pharmaceutically acceptable carrier. In the present invention a "therapeutically effective amount" is any amount of a compound which, when administered to a subject suffering from a disorder against which the compound is effective, causes reduction, remission or regression of the disorder. In one embodiment, the therapeutically effective amount is an amount from about 0.01 mg per subject per day to about 500 mg per subject per day, preferably from about 0.1 mg per subject per day to about 60 mg per subject per day, and most preferably from about 1 mg per subject per day to about 20 mg per subject per day. In the practice of this invention, the "pharmaceutically acceptable carrier" is any physiological carrier known to those of ordinary skill in the art useful in formulating pharmaceutical compositions.

The invention includes the pharmaceutically acceptable salts and complexes of all the compounds described herein. The salts include but are not limited to the following acids and bases. Examples of suitable inorganic acids include, but are not limited to, hydrochloric acid, hydrofluoric acid, hydrobromic acid, hydroiodic acid, sulfuric acid and boric acid. Examples of suitable organic acids include but are not limited to acetic acid, trifluoroacetic acid, formic acid, oxalic acid, malonic acid, succinic acid, tartaric acid, maleic acid, fumaric acid, methanesulfonic acid, trifluoromethanesulfonic acid, benzoic acid, glycolic acid, lactic acid, citric acid and mandelic acid. Examples of suitable inorganic bases include, but are not limited to, ammonia, hydroxyethylamine and hydrazine. Examples of suitable organic bases include, but are not limited to, methylamine, ethylamine, trimethylamine, triethylamine, ethylenediamine, hydroxyethylamine, morpholine, piperazine and guanidine. The invention further provides for the hydrates and polymorphs of all of the compounds described herein.

In one preferred embodiment, the pharmaceutical carrier may be a liquid and the pharmaceutical composition would be in the form of a solution. In another equally preferred embodiment, the pharmaceutically acceptable carrier is a solid and the pharmaceutical composition is in the form of a powder or tablet. In a further embodiment, the pharmaceutical carrier is a gel and the pharmaceutical composition is in the form of a suppository or cream. In a further embodiment, the compound may be formulated as part of a pharmaceutically acceptable transdermal patch.

A solid carrier can include one or more substances which may also act as flavoring agents, lubricants, solubilizers, suspending agents, fillers, glidants, compression aids, binders or tablet-disintegrating agents; it can also be an encapsulating material. In powders, the carrier is a finely divided solid which is in admixture with the finely divided active ingredient. In tablets, the active ingredient is mixed with a carrier having the necessary compression properties in suitable proportions and compacted in the shape and size desired. The powders and tablets preferably contain up to 99% of the active ingredient. Suitable solid carriers include, for examples, calcium phosphate, magnesium stearate, talc, sugars, lactose, dextrin, starch, gelatin, cellulose, polyvinylpyrrolidine, low melting waxes and ion exchange resins.

Liquid carriers are used in preparing solutions, suspensions, emulsions, syrups, elixirs and pressurized compositions. The active ingredient can be dissolved or suspended in a pharmaceutically acceptable liquid carrier such as water, an organic solvent, a mixture of both, or pharmaceutically acceptable oils or fats. The liquid carrier can contain other suitable pharmaceutical additives such as solubilizers, emulsifiers, buffers, preservatives, sweeteners, flavoring agents, suspending agents, thickening agents, colors, viscosity regulators, stabilizers or osmo-regulators. Suitable examples of liquid carriers for oral and parenteral administration include water (partially containing additives as above, e.g. cellulose derivatives, preferably sodium carboxymethyl cellulose solution), alcohols (including monohydric and polyhydric alcohols, e.g. glycols) and their derivatives, and oils (e.g. fractionated coconut oil and arachis oil). For parenteral administration, the carrier can also be an oily ester such as ethyl oleate and isopropyl myristate. Sterile liquid carriers are useful in sterile liquid form compositions for parenteral administration. The liquid carrier for pressurized compositions can be halogenated hydrocarbon or other pharmaceutically acceptable propellant, which are useful for intranasal administration.

Liquid pharmaceutical compositions which are sterile solutions or suspensions can be utilized for intramuscular, intrathecal, intratracheal, epidural, intraperitoneal or subcutaneous injections. Sterile solutions can also be administered intravenously. The compounds may be prepared as a sterile solid composition which may be dissolved or suspended at the time of administration using sterile water, saline, or other appropriate sterile injectable medium. Carriers are intended to include necessary and inert binders, suspending agents, lubricants, flavorants, sweeteners, preservatives, dyes and coatings.

The compound can be administered orally in the form of a sterile solution or suspension containing other solutes or suspending agents, for example, enough saline or glucose to make the solution isotonic, bile salts, acacia, gelatin, sorbitan monoleate, polysorbate 80 (oleate esters of sorbitol and its anhydrides copolymerized with ethylene oxide) and the like.

The compound can also be administered orally either in liquid or solid composition form. Compositions suitable for oral administration include solid forms such as pills, capsules, granules, tablets and powders, and liquid forms such as solutions, syrups, elixirs and suspensions. Forms useful for parenteral administration include sterile solutions, emulsions and suspensions.

Examples of suitable pharmaceutical carriers include any of the standard pharmaceutically accepted carriers known to those of ordinary skill in the art. Examples of such pharmaceutical carriers include, but are not limited to, phosphate buffered saline solution, water, emulsions such as oil/water emulsions or a triglyceride emulsion, various types of wetting agents, tablets, coated tablets and capsules. A suitable pharmaceutically acceptable carrier may be selected taking into account the chosen mode of administration.

Besides containing an effective amount of the compounds described herein the pharmaceutical compositions may also include suitable diluents, preservatives, solubilizers, emulsifiers, adjuvant and/or carriers.

The resulting pharmaceutical compositions may be liquids or lyophilized or otherwise dried formulations. Examples of suitable diluents include, but are not limited to, Tris-HCL, Tris-acetate and Tris-phosphate. The diluents employed may vary in their buffer content, pH and/or ionic strength. Examples of representative additives which may be used in the present invention include, but are not limited to, albumin or gelatin to prevent absorption to surfaces, detergents (e.g., Tween 20, Tween 80, Pluronic F68, bile acid salts), solubilizing agents (e.g., Thimerosal, benzyl alcohol), bulking substances or tonicity modifiers (e.g., lactose, mannitol), covalent attachment of polymers such as polyethylene glycol to the protein, complexation with metal ions, or incorporation of the material into or onto particulate preparation of polymeric compounds such as polylactic acid, polyglycolic acid, polyvinyl pyrrolidone, etc. or into liposomes, microemulsions, micelles, unilamellar or multilamellar vesicles, erythrocyte ghosts, or spheroplasts. Such compositions will influence the physical state, solubility, stability, rate of in vivo release, and rate of in vivo clearance of the compounds.

Examples of optional ingredients which may be included in the pharmaceutical compositions of the present invention include antioxidants, e.g., ascorbic acid; low molecular weight (less than about ten residues) polypeptides, i.e., polyarginine or tripeptide; proteins, such as serum albumin, gelatin, or immunoglobulins; amino acids, such as glycine, glutamine acid, aspartic acid, or arginine; chelating agents such as EDTA; and sugar alcohols such as mannitol or sorbitol.

The choice of composition will depend on the physical and chemical properties of the compounds. Controlled or sustained release compositions include formulation of lipophilic depots (e.g., fatty acids, waxes, oils). Also comprehended by the invention are particulate compositions coated with polymers (e.g., poloxamers or poloxamines) and compounds coupled to antibodies directed against tissue-specific receptors, ligands or antigens or coupled to ligands of tissue-specific receptors. Other embodiments of the compositions of the invention incorporate particulate forms protective coatings, protease inhibitors or permeation enhancers for various routes of administration, including parenteral, pulmonary nasal and oral.

suitable topical formulations include gels, creams, solutions, emulsions, carbohydrate polymers, biodegradable matrices thereof; vapors, mists, aerosols, or other inhalants. The compounds of the present invention may be encapsulated in a wafer, wax, film or solid carrier, including chewing gums. Permeation enhancers to aid in transport to movement across the epithelial layer are also known in the art and include, but are not limited to, dimethyl sulfoxide and glycols.

Optimal dosages to be administered may be determined by those skilled in the art, and will vary with the particular compound in use, the strength of the preparation, the mode of administration, and the advancement of the disease condition. Additional factors depending on the particular subject being treated, including subject age, weight, gender, diet, and time of administration, will result in a need to adjust dosages. Administration of the compound may be effected continuously or intermittently. One skilled in the art will readily appreciate'that appropriate biological assays will be used to determine the therapeutic potential of the claimed compounds for treating α₂-mediated disorders, in particular the disorders described herein.

The present invention additionally provides for the use of a compound for the manufacture of a pharmaceutical composition for treating an α₂ adrenergic receptor associated disorder in a subject, whereby the compound is used in an amount effective to treat the disorder and whereby the compound has the structure: wherein each of Z1, Z2 and Z3 is N or CR₂, with the proviso that either one of Z1, Z2 or Z3 is N and the others of Z1, Z2 or Z3 are CR₂, or both Z1 and Z3 are N and Z2 is CR₂; wherein R₁ is H; F; straight chained or branched C₁ - C₄ alkyl, C₁ - C₄ monofluoroalkyl or C₁ - C₄ polyfluoroalkyl; straight chained or branched C₁ - C₄ alkoxy, -OH; or - (CH₂) qOH; wherein each R₂ is independently H; F; Cl; Br, I; -NO₂, -CN; straight chained or branched C₁ - C₄ alkyl; C₁ - C₄ monofluoroalkyl or C₁ - C₄ polyfluoroalkyl; straight chained or branched C₁ - C₄ alkoxy; -OH; - (CH₂)_qOH; -COR₄; CO₂R₄; CONHR₄; phenyl; or benzyl; wherein each R₄ is independently H; straight chained or branched C₁ - C₄ alkyl, C₁ - C₄ monofluoroalkyl or C₁ - C₄ polyfluoroalkyl; or phenyl; and wherein q is each independently 0, 1, 2 or 3; or a pharmaceutically acceptable salt thereof.

Examples of α₂ adrenergic receptor associated disorders which may be treated in accordance with the subject invention include, but are not limited to, hypertension, pain, glaucoma, alcohol and drug withdrawal, rheumatoid arthritis, ischemia, migraine, cognitive deficiency, spasticity, diarrhea and nasal congestion.

In a specific embodiment of the present invention the α₂ adrenergic receptor associated disorder is migraine headache, hypertension or glaucoma.

The present invention additionally provides for the use of a compound for the manufacture of a pharmaceutical composition for treating pain in a subject, whereby the compound is used in an amount effective to treat the pain and whereby the compound has the structure: wherein each of Z1, Z2 and Z3 is N or CR₂, with the proviso that either one of Z1, Z2 or Z3 is N and the others of Z1, Z2 or Z3 are CR₂, or both Z1 and Z3 are N and Z2 is CR₂; wherein R₁ is H; F; straight chained or branched C₁ - C₄ alkyl, C₁ - C₄ monofluoroalkyl or C₁ - C₄ polyfluoroalkyl; straight chained or branched C₁ - C₄ alkoxy, -OH; or - (CH₂) qOH; wherein each R₂ is independently H; F; Cl; Br; I; -NO₂, -CN; straight chained or branched C₁ - C₄ alkyl; C₁ - C₄ monofluoroalkyl or C₁ - C₄ polyfluoroalkyl; straight chained or branched C₁ - C₄ alkoxy; -OH; - (CH₂) qOH; -COR₄; CO₂R₄; CONHR₄; phenyl; or benzyl; wherein each R₄ is independently H; straight chained or branched C₁ - C₄ alkyl, C₁ - C₄ monofluoroalkyl or C₁ - C₄ polyfluoroalkyl; or phenyl; and wherein q is each independently 0, 1, 2 or 3; or a pharmaceutically acceptable salt thereof.

This invention will be better understood from the Experimental Details which follow. However, one skilled in the art will readily appreciate that the specific methods and results discussed are merely illustrative of the invention as described more fully in the claims which follow thereafter.

Experimental Details :

The compounds of Examples 32-44 may be obtained using the methods depicted in Schemes 5 and 6. Examples 32-38 were prepared using the general scheme shown in Scheme 5, and Examples 39-44 were prepared according to Scheme 6.

Abbreviations in Schemes 5 and 6:

n-BuLi

n-butyl lithium

DMF

dimethylformamide

LDA

lithium diisopropyl amide

Me

methyl

Et

ethyl

Ph

phenyl

RT

room temperature

DMSO

dimethyl sulfoxide

AcCl

acetyl chloride

Py

pyridine

THF

tetrahydrofuran

TBDMS

t-butyl dimethylsilyl

Example 32 4-(4,5-Dihydro-1H-imidazol-4-ylmethyl)-quinoline fumarate

Step A. 2-(Benzhydrylideneamino)-3-quinolin-4-yl-propionitrile. To N-(Diphenylmethylene)aminoacetonitrile (0.360 g, 1.633 mmol) in 10 ml of anhydrous THF and HMPA (hexamethyl phosphoramidite) (0.38 ml, 2.12 mmol), at -78 °C, LDA (2.0 M, 1.06 ml, 2.12 mmol) was added dropwise over a period of 5 minutes. The color of solution turns from colorless to yellow to dark brown. It was then stirred at -78 °C for one hour. 4-Chloromethylquinoline (0.29 g, 1.63 mmol) was added dropwise over a period of 5 minutes and the reaction mixture was slowly brought to room temperature over a period of five minutes. The reaction mixture was quenched by addition of ice and partitioned between EtOAc (20 ml) and water (5 ml). The organic layer was dried over sodium sulfate, filtered concentrated and column purified (hexanes:EtOAc; 3.5:1.5) to give 0.155,g (26%) of the product as a syrup, which was used as such for the subsequent step.

Step B. 2-Amino-3-quinolin-4-yl-propionitrile. To 2-(Benzhydrylideneamino)-3-quinolin-4-yl-propionitrile (0.155 g, 4.29 mmol) in 5 ml dioxane, 1N HCl (1.3 ml, 12.8 mmol) was added and the reaction mixture stirred at room temperature overnight. The solution was concentrated under reduced pressure, partitioned between 10 ml water and EtOAc (10 ml). The organic layer was dried over sodium sulfate filtered and concentrated to give 2-Amino-3-quinolin-4-yl-propionitrile 0.036 g (43%) which was used as such for the subsequent step.

Step C. 3-Quinolin-4-yl-propane-1,2-diamine. To 2-Amino-3-quinolin-4-yl-propionitrile (0.036 g, .0.18 mmol) in 10 ml of ethanol, ammonia gas was bubbled for 15 minutes. 1 g of Raney Ni (washed with 2 x 50 ml water and 2 x 50 ml ethanol) was added to the solution and the reaction mixture was hydrogenated at 50 psi for 2 hours. The reaction mixture was filtered over celite and concentrated to give 0.250 g (50%) of the product which was used as such for the subsequent step.

Step D. 4-(4,5-Dihydro-1H-imidazol-4-ylmethyl)-quinoline. To 3-Quinolin-4-yl-propane-1,2-diamine (0.080 g, 3.98 mmol) in 5 ml of dry dichloromethane, formimidic acid ethyl ester hydrochloride (0.174 g, 7.96 mmol) (Ohme, R. et al. Angew.Chem.Int.Engl.Ed. 1967, 6, 90.) was added. The reaction mixture was stirred overnight at room temperature. Aqueous ammonia (2 ml) was added to the reaction mixture and was partitioned between EtOAc. (2 x 5 ml) and water. The organic layer was dried, filtered and concentrated to give 0.084 g (100%) of the product as a syrup.

Step E. 4-(4,5-Dihydro-1H-imidazol-4-ylmethyl)-quinoline fumarate. To 4-(4,5-Dihydro-1H-imidazol-4-ylmethyl)-quinoline (0.76 g, 0.359 mmol) in 5 ml ethanol, fumaric acid (0.041 g, 0.359 mmol) was added and the solution was heated till all the fumaric acid dissolves. The reaction mixture was concentrated to yield 0.077 (100%) of a solid which was recrystallized from isopropanol: m.p. 180-182 °C; Anal. Calcd. for C₁₃H₁₃N_3.1.5 fumaric acid. 0.1 H₂O: C, 58.94; H, 5.00; N, 10.85. Found: C, 58.99; H, 5.03; N, 10.84.

Example 33 4-[1-(1H-Imidazol-4-yl)-ethyl]-quinoline dihydrochloride

Step A. 1-Quinolin-4-yl-ethanol. To 4-quinolinecarbaldehyde (2 g, 12.73 mmol) in 20 ml anhydrous ether, MeLi (1.4M, 10 ml, 13.9 mmol) was added dropwise over a period of five minutes at 0°C. The reaction mixture was stirred at room temperature for 3 hours. The solution was partitioned between ether (20 ml) and water (10 ml) . The organic layer was dried over sodium sulfate, filtered and concentrated to give 1.43 g (59%) of the product which was then used as such for the subsequent step.

Step B. 4-(1-Chloroethyl)-quinoline. To 1-Quinolin-4-yl-ethanol (1.4 g, 8.09 mmol) in 15 ml chloroform, thionyl chloride (1.8 ml, 20.2 mmol) was added dropwise over a five minute period at room temperature. Stirring was continued for 30 minutes after which the reaction mixture was cooled to 0 °C and quenched carefully by the addition of saturated aqueous NaHCO₃ (20 ml). The chloroform layer was dried over sodium sulfate, filtered and concentrated. Column purification (hexane:ethyl acetate; 1.5:3.5) gave 1.54 g (100%) of the product as a syrup which was used as such for the subsequent step.

Step C. 2-(Benzhydrylideneamino)-3-quinolin-4-yl-butyronitrile. To N-(Diphenylmethylene)arninoacetonitrile (2.26 g, 10.2 mmol) in 10 ml of anhydrous THF and HMPA (2.17 ml, 12.14 mmol), at -78 °C, LDA (2.0 M, 6.0 ml, 12.14 mmol) was added dropwise over a period of 5 minutes. The color of solution turns from colorless to yellow to dark brown. It was then stirred at -78 °C for one hour. Then 4-(1-Chloroethyl)-quinoline (1.79 g, 9.34 mmol) was added dropwise and the reaction mixture was slowly brought to room temperature over a period of five minutes, quenched by addition of ice and partitioned between EtOAc (20 ml) and water (5ml). The organic layer was dried over sodium sulfate, filtered, concentrated and column purified (hexanes:EtOAc; 3.5:1.5) to give 3.0 g (86%) of the product as a syrup which was used as such for the subsequent step.

Step D. 2-Amino-3-quinolin-4-yl-butyronitrile. To 2-(Benzhydrylideneamino)-3-quinolin-4-yl-butyronitrile (3.0 g, 7.3 mmol) in 30 ml dioxane, 1N HCl (30 ml, 29.99 mmol) was added and the reaction mixture stirred at room temperature overnight. The solution was then concentrated under reduced pressure, partitioned between water (10 ml) and EtOAc (10 ml). The organic layer was dried over sodium sulfate, filtered and concentrated to give 1.58 g (88%) of the product which was used as such for the subsequent step.

Step E. 3-Quinolin-4-yl-butane-1,2-diamine. To 2-Amino-3-quinolin-4-yl-butyronitrile (1.58 g, 6.42 mmol) in 10 ml of ethanol, ammonia gas was bubbled for 15 minutes. 2 g of Raney Ni (washed with 2 x 50 ml water and 2 x 50 ml ethanol) was added to the solution and the reaction mixture was hydrogenated at 50 psi for 2 hours, filtered over celite and concentrated to give 1.54 g (96%) of the product which was then used as such for the subsequent step.

Step F. 4-[1-(4,5-Dihydro-1H-imidazol-4-yl)-ethyl]quinoline. To 3-Quinoilin-4-yl-butane-1,2-diamine (1.54 g, 7.16 mmol) in 5 ml of dry dichloromethane, formimidic acid ethyl ester hydrochloride (1.57 g, 14.3 mmol) was added. The reaction mixture was stirred overnight at room temperature. Aqueous ammonia (2 ml) was added to the reaction mixture and was partitioned between EtOAc (2 x 5 ml) and water. The organic layer was dried, filtered and concentrated to give 1.16 g (73%) of the product as a syrup which was used for the subsequent step.

Step G. 4-[1-(1H-Imidazol-4-yl)-ethyl]-quinoline. To oxalyl chloride (0.85 µl, 0.976 mmol) in 5 ml of anhydrous dichloromethane at -78 °C, dimethylsulfoxide (0.14 ml, 1.95 mmol) was added over a five minute period. After stirring for 5 minutes at the same temperature, 4-[1-(4,5-Dihydro-1H-imidazol-4-yl)-ethyl]quinoline (0.200 g, 0.888 mmol) was added slowly and the reaction mixture was stirred for a further 20 minutes at -78 °C. Triethylamine (0.62 ml, 4.44 mmol) was added and the reaction mixture was stirred for 5 minutes at -78 °C and then 20 minutes at room temperature. The reaction mixture was concentrated under reduced pressure and partitioned between EtOAc (10 ml) and water (5 ml). The organic layer was dried over sodium sulfate, filtered, concentrated and column purified [EtOAc:MeOH:Methanol NH₃ (1.0 M); 3.5:1:0.5) to give 0.100 g (51%) of the product as a syrup.

Step H. 4-[1-(1H-Imidazol-4-yl)-ethyl]-quinoline dihydrochloride. To 4-[1-(1H-Imidazol-4-yl)-ethyl]-quinoline (0.067, 0.300 mmol) in 5 ml methanol, 3 ml of HCl in dioxane was added and the reaction mixture was concentrated under reduced pressure to give 0.067 g, (100%) of the product as a pale yellow solid which was recrystallized from isopropanol: m.p. 276-278 °C; Anal. Calcd. for C₁₄H₁₅N₃Cl₂ 0.6 mole H₂O: C, 54.77; H, 5.32; N, 13.69. Found: C, 54.93; H, 4.94; N, 13.28.

Example 34 4-[1-(1H-Imidazol-4-yl)-propyl]-quinoline dihydrochloride

Step A. 4-[1-(1H-Imidazol-4-yl)-propyl]-quinoline. This compound was prepared starting from 4-quinolinecarboxaldehyde using experimental conditions outlined for example 33, except for substituting MeLi in step A with EtMgBr.

Step B. 4-[1-(1H-Imidazol-4-yl)-propyl]-quinoline dihydrochloride. To 4-[1-(1H-Imidazol-4-yl)-propyl]-quinoline (0.185, 0.779 mmol) in 5 ml methanol, 3 ml of HCl in dioxane was added and the reaction mixture was concentrated under reduced pressure to give 0.240 g,(100%) of the product as a foam.

Example 35 4-[1-(1H-Imidazol-4-yl)-ethyl]-2-methyl-quinoline dihydrochloride

Step A. 4-[1-(1H-Imidazol-4-yl)-ethyl]-2-methyl-quinoline. This compound was prepared starting from 2- Methyl -4-quinolinecarbaldehyde (Minisci, F. et al. J. Org. Chem. 1986, 51, 536) and using experimental conditions outlined for example 33.

Step B. 4-[1-(1H-Imidazol-4-yl)-ethyl]-2-methyl-quinoline dihydrochloride. To 4-[1-(1H-Imidazol-4-yl)-ethyl]-2-methyl-quinoline (0.062, 0.261 mmol) in 5 ml methanol, 3 ml of HCl in dioxane was added and the reaction mixture was concentrated under reduced pressure to give 0.080 g, (100%) of the product as a pale yellow solid which was crystallized from isopropanol-ether: m.p. 238-240 °C; Anal. Calcd. for C₁₅H₁₇N₃Cl₂ 1.0 mole H₂O: C, 54.86; H, 5.82. Found: C, 54.83; H, 5.99.

Example 36 4-[1-(1H-Imidazol-4-yl)-ethyl]-2-phenyl-quinoline dihydrochloride

Step A. 1-(2-phenylquinolin-4-yl)-ethanone. To methyl 2-phenyl-4-quinolinecarboxylate (1 g, 3.80 mmol) in 10 ml ether, at 0°C was added MeLi (1.4M, 3.0 ml, 4.1 mmol) dropwise over a five minute period. The reaction mixture was stirred at 0°C for 30 minutes and quenched by the addition of 10 ml of water. The ether layer was separated, dried over sodium sulfate, filtered, concentrated and column purified (hexane:EtOAc; 4.5:0.5) to give 0.233 g (23%) of the product as a syrup which was used as such for the subsequent step.

Step B. 1-(2-phenylquinolin-4-yl)-ethanol. To 1-(2-phenylquinolin-4-yl)-ethanone (0.233 g, 0.943 mmol) in 5 ml methanol, at room temperature sodium borohydride (0.036 g, 0.943 mmol) was added and the solution stirred for 30 minutes. The reaction mixture was concentrated and partitioned between EtOAc (10 ml) and water (5 ml). The organic layer was dried over sodium sulfate, filtered, concentrated and column purified (hexane:EtOAc; 3.5:1.5) to give 0.145 g (62%) of the product as a syrup which was used as such for the subsequent step.

Step C. 4-[1-(1H-Imidazol-4-yl)-ethyl]-2-phenyl-quinoline. This compound was prepared starting from 1-(2-phenylquinolin-4-yl)-ethanol (step B) and following experimental conditions outlined for example 33.

Step D. 4-[1-(1H-Imidazol-4-yl)-ethyl]-2-phenyl-quinoline dihydrochloride. To 4-[1-(1H-Imidazol-4-yl)-ethyl]-2-phenyl-quinoline (0.02 g, 0.066 mmol) in 5 ml methanol, 3 ml of HCl in dioxane was added and the reaction mixture was concentrated under reduced pressure to give 0.025 g, (100%) of the product as a pale yellow solid which was crystallized from isopropanol-ethyl acetate: m.p. 175-180 °C; Anal. Calcd. for C₂₀H₁₉N₃Cl₂ 1.0 mole H O: C, 64.52; H,5.14; N, 11.29., Found: C, 64.83; H, 5.59; N, 11.23.

Example 37 4-[1-(1H-Imidazol-4-yl)-ethyl]-isoquinoline dihydrochloride

Step A. 4-[1-(1H-Imidazol-4-yl)-ethyl]-isoquinoline. This compound was prepared starting from Isoquinoline-4-carbaldehyde (Minisci, F. et al. J. Org. Chem. 1986, 51, 536) and using experimental conditions outlined for example 33.

Step B. 4-[1-(1H-Imidazol-4-yl)-ethyl]-isoquinoline dihydrochloride. To 4-[1-(1H-Imidazol-4-yl)-ethyl]-isoquinoline (0.105, 0.470 mmol) in 5 ml methanol, 3 ml of HCl in dioxane was added and the reaction mixture was concentrated under reduced pressure to give 0.105 g,(86%) of the product as a brown solid which was crystallized from isopropanol: m.p. 185-190 °C; Anal. Calcd. for C₁₄H₁₅N₃Cl₂ 0.9mole H₂O: C, 53.82; H, 5.42; N, 13.45. Found: C, 54.01; H, 5.77; N, 13.98.

Example 38 4-[1-(1H-Imidazol-4-yl)-propyl]-isoquinoline dihydrochloride

Step A. 4-[1-(1H-Imidazol-4-yl)-propyl]-isoquinoline. This compound was prepared starting from Isoquinoline-4-carbaldehyde and using experimental conditions outlined for example 33 except for substituting MeLi in step A with EtMgBr.

Step B. 4-[1-(1H-Imidazol-4-yl)-propyl]-isoquinoline dihydrochloride. To 4-[1-(1H-Imidazol-4-yl)-propyl]-isoquinoline (0.077 g, 0.324 mmol) in 5 ml methanol, 3 ml of HCl in dioxane was added and the reaction mixture was concentrated under reduced pressure to give 0.086 g, (86%) of the product as a yellow solid which was crystallized from isopropanol-ether: m.p. 173-176 °C; Anal. Calcd. for C₁₅H₁₇N₃Cl₂ 0.6 mole dioxane: C, 55.39; Hz, 5.70, N, 11.54. Found: C, 55.85; H, 6.09; N, 11.15.

Example 39 (1H-Imidazol-4-yl)-quinolin-4-yl-methanol dihydrochloride

Step A. 2-(tert-Butyldimethylsilyl)-4-(hydroxyquinolin-4-yl-methyl)-imidazole-1-sulfonic acid dimethylamide. To N,N-dimethylsulfamoyl-2-(tert-butyldimethylsilyl)imidazole (0.165 g, 1.05 mmol) (Chadwick, D.J. et al. J.Chem.Soc.Perkin Trans. I. 1984, 481) in 8 ml THF, n-BuLi ( 0.55 ml, 1.1 mmol) was added over a period of 5 minutes at -78 °C and the reaction mixture was stirred for 30 minutes at the same temperature. 4-quinolinecarbaldehyde (0.165 g, 1.05 mmol) was added neat to the solution and the reaction mixture was stirred for 10 minutes at -78 °C and then at room temperature for 30 minutes. The reaction mixture was partitioned between EtOAc (50 ml) and water (10 ml). The organic layer was dried over sodium sulfate, filtered and concentrated to yield 0.462 g (100%) of the product.

Step B. (1H-Imidazol-4-yl)-quinolin-4-yl-methanol. To (1H-Imidazol-4-yl)-quinolin-4-yl-methanol (0.150 g, 0.32 mmol), 7 ml of 1.5N HCl was added and the contents refluxed for 2 hours. The reaction mixture was concentrated, partitioned between water (10 ml) and EtOAc (2 x 10 ml). The organic layer was dried over sodium sulfate, filtered concentrated and column purified (CH₂Cl₂: MeOH: Methanol-NH₃ (1.0M) (4.5:0.25:0.25) to yield 0.072 g (100%) of the product.

Step C. (1H-Imidazol-4-yl)-quinolin-4-yl-methanol dihydrochloride. To (1H-Imidazol-4-yl)-quinolin-4-yl-methanol (0.030 g, 0.133 mmol) in 5 ml methanol, 3 ml of HCl in dioxane was added and the reaction mixture was concentrated under reduced pressure to give 0.033 g, (85%) of the product as a solid: m.p. 200-202 °C; Anal. Calcd. for C₁₃H₁₃N₃OCl₂ 1.0 H₂O: C, 49.38; Hz, 4.78; N, 13.29. Found: C, 49.52; H 4.72; N 13.52.

Example 40 4-[(1H-Imidazol-4-yl)-methoxymethyl]quinoline dihydrochloride

Step A. 2-(tert-Butyldimethylsilyl)-4-(methoxyquinolin-4-yl-methyl)-imidazole-1-sulfonic acid dimethylamide. To pentane washed sodium hydride (0.048 g, 1.2 mmol) in 5 ml of THF at 0 °C, 2-(tert-Butyldimethylsilyl)-4-(hydroxyquinolin-4-yl-methyl)-imidazole-1-sulfonic acid dimethylamide (example 8, step A) (0.375 g, 0.811 mmol) was added slowly over a period of 5 minutes. After stirring at room temperature for 15 minutes, it was again cooled to 0°C and methyl iodide (0.1 ml, 1.62 mmol) was added neat. The reaction mixture was stirred at room temperature for 1 hour, concentrated under reduced pressure and partitioned between EtOAc (10 ml) and water (10 ml). The organic layer was dried over sodium sulfate, filtered and concentrated to yield 0.32 g (83%) of the product as a syrup.

Step B. 4-[(1H-Imidazol-4-yl)-methoxymethyl]quinoline. To 2-(tert-Butyldimethylsilyl)-4-(methoxyquinolin-4-yl-methyl)-imidazole-1-sulfonic acid dimethylamide. (0.32 g, 0.672 mmol), 7 ml of 1.5N HCl was added and the solution refluxed for two hours. The reaction mixture was concentrated, partitioned between water(10 ml) and EtOAc (2 x 10 ml). The organic layer was dried over sodium sulfate, filtered , concentrated and column purified (CH₂Cl₂: MeOH: methanol-NH₃ (1.0M); (4.5:0.25:0.25) to yield 0.160 g (100%) of the product as a syrup.

Step C. 4-[(1H-Imidazol-4-yl)-methoxymethyl]quinoline dihydrochloride. To 4-[(1H-Imidazol-4-yl)-methoxymethyl]quinoline (0.160 g, 0.66 mmol) in 5 ml methanol, 3 ml of HCl in dioxane was added and the reaction mixture was concentrated under reduced pressure to give 0.116 g, (80%) of the product as a white solid: m.p. 188-190 °C; Anal. Calcd. for C₁₄H₁₅N₃OCl₂ 0.6 mole H₂O: C, 52.06; H; 5.06. Found: C, 52.18; H; 5.40.

Example 41 4-(1H-Imidazol-4-yl-methyl)-quinoline dihydrochloride

Step A. Acetic acid-[2-(tert-Butyldimethylsilyl)-1-dimethylsulfamoyl-1H-imidazol-4-yl]-quinolin-4-yl-methyl ester. To 2-(tert-Butyldimethylsilyl)-4-(hydroxyquinolin-4-yl-methyl)-imidazole-1-sulfonic acid dimethylamide (example 8, step A) (0.750 g, 1.62 mmol) in 8 ml of anhydrous toluene at 0 °C, pyridine (0.16 ml, 1.94 mmol) was added followed by acetyl chloride (0.14 ml, 1.94 mmol). The solution was stirred at room temperature for two hours. It was cooled to 0 °C and ice cubes were added. The reaction mixture was partitioned between toluene (5 ml) and water (5 ml). The organic layer was dried over sodium sulfate, filtered, concentrated under reduced pressure and column purified (hexanes:EtOAc; 1:4) to give 0.84 g (100%) of the product.

Step B. 4-Quinolin-4-yl-methyl-imidazole-1-sulfonic acid dimethylamide. To Acetic acid-[2-(tert-Butyldimethylsilyl)-1-dimethylsulfamoyl-1H-imidazol-4-yl]-quinolin-4-yl-methyl ester (0.895 g, 1.72 mmol) in 10 ml of ethanol, 0.3 g of palladium on carbon (10%) was added and the solution hydrogenated at 40 psi for 18 hours. The solution was filtered over celite and concentrated under reduced pressure to give 0.190 g (53%) of the product as a syrup.

Step C. 4-(1H-Imidazol-4-yl-methyl)-quinoline. To 4-Quinolin-4-yl-methyl-imidazole-1-sulfonic acid dimethylamide (0.16 g, 0.765 mmol), 7 ml of 1.5N HCl was added and the solution refluxed for two hours. The reaction mixture was concentrated, partitioned between water (10 ml) and EtOAc (2 x 10 ml). The organic layer was dried over sodium sulfate, filtered , concentrated and column purified (CH₂Cl₂: MeOH: methanol - NH₃ (1.0M); (4.5:0.25:0.25) to yield 0.080 g (51%) of the product as a syrup.

Step D. 4-(1H-Imidazol-4-yl-methyl)-quinoline dihydrochloride. To 4-(1H-Imidazol-4-yl-methyl)-quinoline (0.08 g, 0.382 mmol) in 5 ml methanol, 3 ml of HCl in dioxane was added and the reaction mixture was concentrated under reduced pressure to give 0.107 g, (100%) of the product as a' solid: m.p. > 300 °C; Anal. Calcd. for C₁₃H₁₃N₃Cl₂ 1.0 mole H₂O: C, 52.02; H, 5.04; N 14.00. Found: C, 52.00; H, 4.81; N, 14.04.

Example 42 4-(1H-Imidazol-4-yl-methyl)-isoquinoline dihydrochloride

Step A. 2-(tert-Butyldimethylsilyl)-4-(hydroxyisoquinolin-4-yl-methyl)-imidazole-1-sulfonic acid dimethylamide. This compound was prepared according to experimental conditions outlined in example 39, step A, starting with isoquinoline-4-carbaldehyde (Gilman, H. et al. J. Org. Chem. 1957, 22, 565.) and N,N-dimethylsulfamoyl-2-(tert-butyldimethylsilyl)imidazole (Chadwick, D.J. et al. J. Chem. Soc. Perkin Trans. I. 1984, 481).

Step B. 2-(tert-Butyldimethylsilyl)-4-(chloroisoquinolin-4-yl-methyl)-imidazole-1-sulfonic acid dimethylamide. This compound was prepared from 2-(tert-Butyldimethylsilyl)-4-(hydroxyisoquinolin-4-yl-methyl)-imidazole-1-sulfonic acid dimethylamide following experimental conditions outlined in example 33, step B.

Step C. 4-Isoquinolin-4-yl-methyl-imidazole-1-sulfonic acid dimethyl amide. To 2-(tert-Butyldimethylsilyl)-4-(chloroisoquinolin-4-yl-methyl)-imidazole-1-sulfonic acid dimethylamide (0.150 g, 0.312 mmol) in 0.6 ml acetic acid ( 0.5mmol), zinc dust (0.300 g, 5.55 mmol) was added and the solution stirred for 24 hours at room temperature. It was neutralized with ammonium hydroxide, EtOAc (20 ml) was added to the solution and filtered. The filtrate was partitioned between ethyl acetate and water (10 ml). The organic layer was dried over sodium sulfate, filtered and concentrated. Purification by column chromatography (EtOAc:MeOH; 4:1) gave 0.075 g (74%) of the product as a syrup.

Step D. 4-(1H-Imidazol-4-yl-methyl)-isoquinoline. To 4-Isoquinolin-4-yl-methyl-imidazole-1-sulfonic acid dimethyl amide (0.110 g, 0.312 mmol), 7 ml of 1.5N HCl was added and the solution refluxed for two hours. The reaction mixture was concentrated, partitioned between water (10 ml) and EtOAc (2 x 10 ml). The organic layer was dried over sodium sulfate, filtered , concentrated and column purified (CH₂Cl₂: MeOH: methanol-NH, (1.0M) ( 4.5:0.25:0.25) to yield 0.0528 g (81%) of the product as a syrup.

Step E. 4-(1H-Imidazol-4-yl-methyl)-isoquinoline dihydrochloride. To 4-(1H-Imidazol-4-yl-methyl)-isoquinoline (0.053 g, 0.253 mmol) in 5 ml methanol, 3 ml of HCl in dioxane was added and the reaction mixture was concentrated under reduced pressure to give 0.071 g, (100%) of the product as a solid. Anal. Calcd. for C₁₃H₁₃N₃Cl₂ 1.3 mole H₂O: C, 51.10; H, 5.15; N, 13.75. Found: C, 51.27; H, 4.97; N, 13.54.

Example 43 1-(1H-Imidazol-4-yl-methyl)-isoquinoline dihydrochloride

Step A. 4-(1H-Imidazol-4-yl-methyl)-isoquinoline. This compound was prepared according to experimental conditions outlined in example 42, starting from isoquinoline-1-carbaldehyde (F.Minisci et al. J. Org. Chem. 1986, 51, 536).

Step B. 1-(1H-Imidazol-4-yl-methyl)-isoquinoline dihydrochloride. To 1-(1H-Imidazol-4-yl-methyl)-isoquinoline (0.124 g, 0.592 mmol) in 5 ml methanol, 3 ml of HCl in dioxane was added and the reaction mixture was concentrated under reduced pressure to give 0.127 g, (74%) of the product as a pale yellow solid which was recrystallized from isopropanol-ether: m.p. 240-242 °C; Anal. Calcd. for C₁₃H₁₁N₃Cl₂ 0.6 mole H₂O: C, 53.29; H, 4.89. Found: C, 53.30; H, 5.04.

Example 44 4-(1H-Imidazol-4-yl-methyl)-3-methylisoquinoline dihydrochloride

Step A. 4-Bromo-3-methylisoquinoline. To 3-methylisoquinoline (0.500 g, 3.49 mmol) in 1 ml nitrobenzene, bromine (0.196 ml, 3.84 mmol) was added and the contents heated in a sealed tube at 180 °C for 4 hours. The solution was cooled to room temperature, neutralized with solid sodium carbonate (pH = 8) and extracted with ethyl acetate (2 x 20 ml). The organic layer was dried over sodium sulfate, filtered, concentrated and column purified (hexane:EtOAc; 4.5:0.5) to give 0.560 g (72%) of the product as syrup.

Step B. 3-methylisoquinoline-4-carbaldehyde. To a solution of n-BuLi ( 2.5M, 0.869 ml, 2.17 mmol) ) in 10 ml anhydrous THF at -50 °C, 4-bromo-3-methylisoquinoline (0.460 g, 2.07 mmol) was added. After 10 minutes of stirring, DMF (0.32 g, 4.14 mmol) was added to the solution. The reaction mixture was allowed to stir at -50 °C for 20 minutes and then at room temperature for 15 minutes. 5 ml of 1N HCl was added and the solution was stirred for another 5 minutes. The reaction mixture was neutralized with saturated solution of NaHCO₃ (25 ml) and partitioned between ethylacetate (2 x 20 ml) and water (10 ml). The organic layer was dried over sodium sulfate, filtered, concentrated and column purified (hexane:EtOAc; 3:2) to give 0.151 g (43%) of the product as a syrup.

Step C. 4-(1H-Imidazol-4-yl-methyl)-3-methylisoquinoline. This compound was prepared from 3-methylisoquinoline-4-carbaldehyde employing reaction conditions outlined in example 42. Yield 0.042 g (81%).

Step D. 4-(1H-Imidazol-4-yl-methyl)-3-methylisoquinoline dihydrochloride. To 4-(1H-Imidazol-4-yl-methyl)-3-methylisoquinoline (0.042 g, 1.88 mmol) in 5 ml methanol, 3 ml of HCl in dioxane was added and the reaction mixture was concentrated under reduced pressure to give 0.042, (76%) of the product as a pale yellow solid which was recrystallized from isopropanol-ether. m.p. 160-165 °C; Anal. Calcd. for C₁₄H₁₃N₃Cl₂ 1.1 mole H₂O: C, 53.21; H, 5.49. Found: C, 53.02; H, 5.75.

It is understood that additional compounds may be synthesized under the general synthetic schemes referred to herein using appropriately substituted starting materials.

Example 45

As a specific embodiment of an oral composition of a compound of this invention, 100 mg of one of the compounds described herein is formulated with sufficient finely divided lactose to provide a total amount of 580 to 590 ma to fill a size O hard gel capsule.

Pharmacological profiles of the compounds at cloned human α adrenergic receptors Binding and functional assays were performed using stably transfected cells expressing human α adrenergic receptors.

Equilibrium competition binding assays were performed with membrane preparations from cultured LM(tk-) cells stably transfected with the cloned human adrenoceptor subtypes except for α_2b, which was expressed in Y-1 cells, using [³H]prazosin for α₁ receptors and [³H]rauwolscine for ₂α receptors.

Protocol for the determination of the potency of ligands The activity of the compounds at the different receptors was determined in vitro using cultured cell lines, each selectively expressing only one α adrenergic receptor subtype (α_1a, α_1b, α_1c, α_2a, α_2b, or α_2c ). These cell lines were prepared by transfecting cloned cDNA or cloned genomic DNA or constructs containing both genomic DNA and cDNA encoding the human α adrenergic receptors as described below.

Human α_2a Adrenergic Receptor: The entire coding region of α_2a (1350 bp), including 1.0 kilobasepairs of 5' untranslated sequence (5'UT) and 100 bp of 3' untranslated sequence (3'UT), was cloned into the SmaI site of the eukaryotic expression vector pCEXV-3. The insert housing this coding region was a 2.5 kb Kpn1/HindIII human placenta genomic fragment which was end-blunted by either T₄ polymerase or Klenow fragment of DNA polymerase. Stable cell lines were obtained by co-transfection with the plasmid pGCcos3neo (plasmid containing the α_2a receptor gene) and the plasmid pGCcos3neo (plasmid containing the aminoglycoside transferase gene) into LM(tk-), CHO, and NIH3T3 cells, using calcium phosphate technique. The cells were grown in a controlled environment (37°C, 5% CO₂) as monolayers in Dulbecco's modified Eagle's Medium (GIBCO, Grand Island, NY) containing 25 mM glucose and supplemented with 10% bovine calf serum, 100 units/mL penicillin g, and 100 mg/mL streptomycin sulfate. Stable clones were then selected for resistance to the antibiotic G-418 (1 mg/mL) , and membranes were harvested and assayed for their ability to bind [³H]rauwolscine as described below (see "Radioligand Binding Assays").

Human α_2b Adrenergic Receptor: The entire coding region of α_2b (1350 bp), including 393 bp of 5' untranslated sequence and 11 bp of 3' untranslated sequence, was cloned into the eukaryotic expression vector pcEXV-3. Stable cell lines were selected as described above.

Human α_2c Adrenergic Receptor: The entire coding region of α_2c (1383 bp), including 2 bp of 5' UT and 400 bp of 3' UT, was cloned into the Smal site of the eukaryotic expression vector pCEXV-3. The insert housing this coding region was a 1.8 kb Ncol/EcoRI human spleen genomic fragment which was end-blunted by either T₄ polymerase or Klenow fragment of DNA polymerase. Stable cell lines were selected as described above.

Stable cell lines expressing the human α₂ adrenergic receptors described above as well as stable cell lines expressing the human α₁ adrenergic receptors have been deposited with the American Type Culture Collection (ATCC), 12301 Parklawn Drive, Rockville, Maryland, 20852, U.S.A., under the provisions of the Budapest Treaty for the International Recognition of the Deposit of Microorganisms for the Purposes of Patent Procedure. The cell line expressing the human α_2a receptor is designated L-α_2A and was deposited on November 6, 1992, under ATCC Accession Number CRL-11180. The cell line expressing the human α_2b receptor is designated L-NGC-α_2B and was deposited on October 25, 1989 under ATCC Accession Number CRL-10275. The cell line expressing the human α_2c receptor is designated L-α_2C and was deposited on November 6, 1992, under ATCC Accession Number CRL-11181.

The cell line expressing the human α_1a receptor is designated L-α_1A and was deposited on September 25, 1992, under ATCC Accession Number CRL-11138. The human α_1a receptor is now known as the "α_1d" receptor due to a nomenclature change by the IUPHAR Nomenclature Committee, as outlined in the 1995 Receptor and Ion Channel Nomenclature Supplement (Watson and Girdlestone, 1995). The cell line expressing the human α_1b receptor is designated L-α_1B and was deposited on September 29, 1992 under ATCC Accession Number CRL-11139. The cell line expressing the human α_1c receptor is designated L-α_1C and was deposited on September 25, 1992, under ATCC Accession Number CRL-11140. The human α_1c receptor was also renamed by the IUPHAR Nomenclature Committee and is now known as the "α_1a" receptor.

Radioligand Binding Assays: The stable cell lines described above were scraped from culture flasks into 5 mL of 5 mM Tris-HCl, 5 nM EDTA, pH 7.5, and lysed by sonication. The cell lysates were centrifuged at 1,000 rpm for 5 min. at 4°C, and the supernatant was centrifuged at 30,000 x g for 20 min. at 4°C. The pellet was suspended in 50 mM Tris-HCl, 1 mM MgCl₂, and 0.1% ascorbic acid at pH 7.5. Binding of the α₂ antagonist [³H]rauwolscine (0.5 nM) or the a₁ antagonist [³H]prazosin (0.5 nM) to membrane preparations of LM(tk-) cells was done in a final volume of 0.25 mL and incubated at 37°C for 20 min. Nonspecific binding was determined in the presence of 10 mM phentolamine. The reaction was stopped by filtration through GF/B filters using a cell harvester. Inhibition experiments routinely consisting of 7 concentrations of the tested compounds were analyzed using a non-linear regression curve-fitting computer program to obtain Ki values.

Measurement of α₂ Agonist Activity: The agonist activity (expressed as pEC₅₀) was measured as a function of the ability to inhibit the forskolin-stimulated synthesis of cyclic adenosine monophosphate (cAMP). The stably transfected cells were incubated in Ham's F10 with 5 mM theophylline, 10 mM HEPES, 17 mM pargyline, and/or appropriate concentrations of forskolin for 20 min. at 37°C in 5% CO₂. The tested compounds were then added to a final concentration of 0.001 nM to 1 mM and incubated for an additional 15 min. at 37°C in 5% CO₂. The medium was aspirated and the reaction was stopped by the addition of 100 mM HCl. To demonstrate competitive antagonism, a dose-response curve for norepinephrine was obtained in parallel using a fixed dose of norepinephrine (0.32 mM). The plates were stored at 4°C for 15 min. and assayed to determine the linear concentration of cAMP. The appropriate dilution was interpolated from the standard curve of cold cAMP. The assessment of cAMP formation was determined by radioimmunoassay (cAMP radioimmunoassay kit; Advanced magnetics, Cambridge, MA). Radioactivity was quantified using a Packard COBRA Auto Gamma counter equipped with data reduction software.

Binding affinities were measured for the compounds of the invention at the six α adrenergic receptor subtypes described above. The compounds were found to be α₂ selective agonists. The compounds were also found to exhibit weak binding to the α₁ receptors relative to the binding of the compounds to the α₂ receptors. Table 1 shows the binding and functional activities of selected compounds at cloned human α₂ adrenergic receptors. Table 1.

Compound	pKi		pKi		pKi
Medetomidine	8.62		8.63		8.27
UK-14,304	8.15		7.44		7.03
Example 36	8.57		7.39		7.79

Claims (12)

1. A compound having the structure: wherein each of Z1, Z2 and Z3 is N or CR₂, with the proviso that either one of Z1, Z2 or Z3 is N and the others of Z1, Z2 or Z3 are CR₂, or both Z1 and Z3 are N and Z2 is CR₂; wherein R₁ is H; F; straight chained or branched C₁ - C₄ alkyl, C₁ - C₄ monofluoroalkyl or C₁ - C₄ polyfluoroalkyl; straight chained or branched C₁ - C₄ alkoxy, -OH; or - (CH₂) qOH; wherein each R₂ is independently H; F; Cl; Br; I; -NO₂, -CN; straight chained or branched C₁ - C₄ alkyl; C₁ - C₄ monofluoroalkyl or C₁ - C₄ polyfluoroalkyl; straight chained or branched C₁ - C₄ alkoxy; -OH; - (CH₂) qOH; -COR₄; CO₂R₄; CONHR₄; phenyl; or benzyl; wherein each R₄ is independently H; straight chained or branched C₁ - C₄ alkyl, C₁ - C₄ monofluoroalkyl or C₁ - C₄ polyfluoroalkyl; or phenyl; and wherein q is each independently 0, 1, 2 or 3; or a pharmaceutically acceptable salt thereof, optionally present as an enantiomer, diastereomer, or as a racemic mixture.
2. The compound of claim 1, wherein the compound comprises the (+) enantiomer.
3. The compound of claim 1, wherein the compound comprises the (-) enantiomer.
4. The compound of claim 1, wherein two of Z1 , Z2 and Z3 are CR₂ and the other is N.
5. The compound of claim 4, wherein at least one R₂ is methyl or phenyl.
6. The compound of claim 4, wherein R₁ is C₁ - C₃ alkyl, C₁ - C₃ alkoxy, or -OH.
7. The compound of claim 6 having the structure:
8. A pharmaceutical composition comprising a therapeutically effective amount of a compound of claim 1 and a pharmaceutically acceptable carrier.
9. Use of a compound of the structure II according to claim 1 or a pharmaceutically acceptable salt thereof, optionally present as an enantiomer, diastereomer, or as a racemic mixture, for the manufacture of a pharmaceutical composition for the treatment of an α₂ adrenergic receptor associated disorder in a subject, whereby the compound is used in an amount effective to treat the disorder.
10. Use according to claim 9, wherein the disorder is migraine headache, hypertension or glaucoma.
11. Use of a compound of the structure II according to claim 1 or a pharmaceutically acceptable salt thereof, optionally present as an enantiomer, diastereomer, or as a racemic mixture for the manufacture of a pharmaceutical composition for the treatment of pain in a subject, whereby the compound is used in an amount effective to treat the pain.
12. Use according to claim 9, wherein the disorder is alcohol and drug withdrawal, rheumatoid arthritis, migraine, ischemia, cognitive deficiency, spasticity, diarrhea or nasal congestion.