INHIBITION OF THE 5-LIPOXYGENASE PATHWAY

Abstract: This invention relates to 4,5-diaryl-2-­ (substituted)imidazoles or pharmaceutically acceptable salts thereof, for use in inhibiting the 5-lipoxygenase pathway of arachidonic acid metabolism, to methods for their preparation and to pharmaceutical compositions containing them.

Description: This invention relates to 4,5-diaryl-2-(substituted)imidazoles or pharmaceutically acceptable salts thereof, for use in inhibiting the 5-lipoxygenase pathway of arachidonic acid metabolism, to methods for their preparation and to pharmaceutical compositions containing them. Several compounds structurally similar to those of the present invention are known to have antiinflammatory, antiarthritic, immunoregulatory, antithrombolic, or antinociceptive activity as exhibited by their activity in various assays. These assays are not useful in detecting compounds which are inhibitors of the 5-lipoxygenase pathway. Thus, the utility of the compounds as 5-lipoxygenase pathway inhibitors was not previously detected. AT-374 198 discloses certain 2-mercaptoimidazoles as having anti-inflammatory and/or antinoiceptive activity. EP-A-4648 discloses further 2-mercaptoimidazoles, again as anti-inflammatory and/or antinoiceptive agents. Chemical Abstracts 1979, 91 , 175 349 6 discloses a series of 2-amino-4,5-diphenyl imidazoles which are unsubstituted at the 3-position. Lombardino et al., U.S. Patent 3,772,441, issued November 13, 1973, disclose preparation of compounds of the formula and the pharmaceutically acceptable acid addition salt thereof, wherein: Ar and Ar¹ are each selected from furyl, thienyl, pyridyl, phenyl and substituted phenyl, wherein said substituents are selected from fluoro, chloro, bromo, and C₁₋₄ alkoxy; R¹ is selected from H or C₁₋₄ alkyl; and R² is selected from trifluoromethyl, C₁₋₄ alkyl, furyl, thienyl, pyridyl, and substituted phenyl wherein said substituents are selected from fluoro, chloro, bromo, or C 1-4 alkoxy. Lombardino et al., J. Med. Chem. , 17 (11), 1182-1188 (1974) disclose the preparation of compounds of the formula wherein Ar and Ar¹ are each selected from methoxyphenyl, 4-ethoxyphenyl, 2-pyridyl and 4-halophenyl; and R is selected from 4-halophenyl, CF₃, phenyl and 4-methoxyphenyl. Bender et al., J. Med. Chem. , 28 , 1169-1177 (1985) disclose the preparation of compounds of the formula wherein R is methyl or ethyl, R¹ is H, methyl or ethyl, R² is 4-methoxyphenyl, and R³ is 4-methoxyphenyl, 4-bromophenyl or 3-fluorophenyl. Cherkofsky et al., U.S. Patent No. 4,190,666, issued February 26, 1980 disclose the preparation of compounds of the formula wherein n is 0, 1 or 2; R¹ is C 1-6 alkyl or polyhalo C 1-6 alkyl; and R² and R³ are independently selected from monosubstituted phenyl wherein said substituent is selected from C 1-4 alkoxy, chloro or fluoro, and pharmaceutically acceptable salts thereof. Zauer et al., Chem. Ber. , 106 , 1628-1636 (1973), disclose the preparation of 4,5-bis-(p-chlorophenyl)-2-(methylthio)imidazole and 4,5-bis(p-methoxypheny)-2-methylimidazole. Ferrini et al., U.S. Patent 4,308,277, issued December 29, 1981 disclose the preparation of compounds of the formula wherein: R¹ and R² are independently selected from thienyl or monosubstituted phenyl wherein said substituents are selected from lower alkoxy and halo; R³ is H or C 1-7 alkyl; and R⁴ is C 1-7 alkyl; and pharmaceutically acceptable salts thereof. Dupont, Belgian Patent Application No. 845,074, published November 2, 1977 discloses the preparation of compounds of the formula wherein: n is 0, 1 or 2; R¹ is mono or polyhalo C 1-4 alkyl or C 1-4 alkyl; and R² and R³ are independently selected from mono-substituted phenyl wherein said substituents are selected from C 1-4 alkoxy, chloro or fluoro, and pharmaceutically acceptable salts thereof. Tanino et al., Bulletin of the Chemical Society of Japan , 45 , 1474-1480 (l972), and White et al., J. Org. Chem. , 29 , 1926-1930 (1964), disclose the preparation of 2,4,5-tri(p-chloropheny)imidazole. Cherkofsky et al., U.S. Patent 4,182,769, issued January 8, 1980, disclose the preparation of compounds of the formula wherein: n is 0, 1 or 2; R¹ is C 1-6 alkyl and mono- and polyhalo C 1-4 alkyl; and R² and R³ are independently selected from mono-substituted phenyl wherein said substituent is selected from C 1-4 alkoxy, Cl or F, and pharmaceutically acceptable salts thereof. Ferrini et al., U.S. Patent 4,461,770, issued July 24, 1984, disclose the preparation of compounds of the formula wherein at least one of the radicals R¹ and R² is a substituted or unsubstituted heteroaryl group and the other is a substituted or unsubstituted aryl group; R³ is H or lower alkyl, n is 0, 1 or 2, and R⁴ is a substituted or unsubstituted aliphatic hydrocarbon radical, and pharmaceutically usable salts thereof. Cherkofsky et al., U.S. Patent 4,159,338, issued June 26, 1979, disclose the preparation of compounds of the formula wherein: n is 0, 1 or 2; R¹ is polyfluoro C 1-2 alkyl; R² and R³ are independently selected from 2-thienyl, 3-thienyl, 3-pyridyl, 2-furyl or monosubstituted phenyl wherein said substituent is selected from C 1-4 alkoxy, Cl or F; and R⁴ is H, and pharmaceutically acceptable acid addition salts thereof. Bender et al., U.S. Patent 4,175,127, issued November 20, 1979, disclose the preparation of compounds of the formula wherein: R³ is H, C 1-6 alkyl or mono- or polyhalo C 1-4 alkyl; and R¹ and R² are the same or different, but one of which always being pyridyl, are pyridyl or mono-substituted phenyl wherein said substituent is selected from lower alkoxy, chloro, fluoro or bromo. Fitzi, et al., U.S. Patent No. 3,940,486, issued February 24, 1976, and Fitzi, et al., U.S. Patent 3,929,807, issued December 30, 1975, disclose the preparation of compounds of the formula wherein: R¹ is halo-substituted phenyl; and one of the groups R² and R³ represents phenyl which is optionally substituted by halo or lower alkoxy and the other is a 6-membered heteroaromatic ring, and salts of such compounds. Lantos, et al., J. Med. Chem. , 27 (1), 72-75 (1984), disclose the preparation of 4-(4-methoxyphenyl)-5-(4-pyridyl)-2-thione-imidazole and 4-(4-fluorophenyl)-5-(4-pyridyl)-2-thione-imidazole. This invention relates to novel compounds of the formula wherein: X¹ is NHCN or NH₂; R¹ and R are independently selected from pyridyl or monosubstituted phenyl wherein said substituent is selected from halo or C 1-4 alkoxy; and Y¹ is H or CN; provided that when X¹ is NH₂, Y¹ is CN, and when X¹ is NHCN, Y¹ is H; or a pharmaceutically acceptable salt thereof. The halo group can be fluoro, chloro, bromo, or iodo. This invention also relates to a pharmaceutical composition comprising an effective, non-toxic 5-lipoxygenase pathway inhibiting amount of a compound of Formula (IA), or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier or diluent. This invention also relates to compounds of Formula (IA) for use in treating rheumatoid arthritis in an animal in need thereof. This invention also relates to the use of compounds of the Formula (I) in the preparation of medicaments for use in treating 5-lipoxygenase pathway mediated disease, other than, or in addition to, rheumatoid arthritis, in an animal, including a mammal, in need thereof, said compounds being of the formula wherein: X is SH, OH, H, S(0) n R², NHCN, NH₂, polyhalo C 1-4 alkyl, or 4-halophenyl; n is 0, 1 or 2; R² is selected from H, C 1-6 alkyl, mono- or polyhalo C 1-4 alkyl, or C 1-4 alkylamino; R and R¹ are independently selected from pyridyl or substituted phenyl wherein said substituent is selected from halo, C 1-4 alkoxy, or C 1-4 alkylthio; provided that when R and/or R¹ are pyridyl, R² is other than C 1-6 alkyl, tetrahaloethyl or C 1-4 perhaloalkyl; Y is H, CN or C 1-4 alkyl; provided that when X is NH₂, Y is CN and when X is NHCN, Y is H; and halo is selected from fluoro, chloro, bromo, or iodo; or a pharmaceutically acceptable salt thereof. The compounds of Formula (I) are useful as 5-lipoxygenase pathway inhibitors. Compounds of this general type are known in the art, but not as 5-lipoxygenase pathway inhibitors. All of the compounds of Formula (IA) are useful as 5-lipoxygenase pathway inhibitors and are novel. The compounds of Formula (IA) are within the scope of Formula (I). The preparation of all the compounds of Formula (I), except for the compounds of Formula (IA), is known and such compounds can be prepared by the methods taught in the previously cited references. The preparation of the compounds of Formula (IA) can be accomplished by reacting a compound of Formula (II) wherein R and R¹ are the same or different and are pyridyl or monosubstituted phenyl wherein the substituent is selected from halo or C 1-4 alkoxy, and X is bromine or chlorine with cyanoguanidine of Formula (III) Preferably one equivalent of the compound of Formula (II) is reacted with three equivalents of cyanoguanidine. The compound of Formula (II), a 2-halo-1,2-diaryl-ethan-1-one or a 2-halo-1,2-diheteroarylethan-1-one can be reacted with an excess of cyanoguanidine typically in a ratio of from 1:1 to 1:5 equivalents of Formula (II) compound to cyanoguanidine in a suitable, unreactive, polar solvent, such as dimethylformamide. The reaction can be conducted at ambient temperature, typically for from about 70 to about l50 hours. Optionally the reaction can be conducted in an inert atmosphere such as nitrogen gas. The reaction mixture is then treated with water, extracted with an appropriate organic solvent, such as methylene chloride and concentrated to yield the desired product. The compound of Formula (II) can be prepared by treatment of the corresponding 1,2-diarylethan-1-one or 1,2-diheteroarylethan-1-one of Formula (IV) wherein R and R¹ are as defined for Formula (II) with a brominating agent such as bromine or pyridinium bromide perbromide, or a similar chlorinating agent. The precurser ethanone of Formula (IV) can be prepared by any one of several methods. One method of preparing the compound of Formula (IV) is by acylation of picolyl sodium by an aryl or heteroaryl carboxylic acid ester according to a reaction exemplified by scheme (A). This reaction can be employed when for compound of Formula (IV), R is pyridyl and R¹ is pyridyl, phenyl, or substituted phenyl. An alternate method of preparing the compound of Formula (IV) can be by an alkoxide catalyzed condensation of an aryl or heteroaryl carboxylic acid ester with an aryl acetic acid ester or arylacetonitrile (ArCH₂C≡N) according to a reaction exemplified by scheme (B). This reaction can be employed when R¹ of the compound of Formula (IV) is pyridyl, phenyl, or substituted phenyl. A third method of preparing the compound of Formula (IV) can be by Friedel Crafts acylation of a substituted benzene by an aryl acetic acid chloride according to reaction scheme (C). A fourth method of preparing the compound of Formula (IV) can be by reduction of a benzoin with tin and hydrochloric acid as exemplified by reaction (D). A fifth method of preparing the compound of Formula (IV) can be is by Curtius rearrangement of an acyl azide of the stilbene carboxylic acid resulting from Perkin condensation of a benzaldehyde with a phenylacetic acid ester as detailed in Hill, D.T., Stringer, O.D., Presentation at the 13th Mid-America Regional Meeting of the American Chemical Society, March (l979) ORG 21. Pharmaceutically acceptable salts and their preparation are well known to those skilled in the art of pharmaceuticals. The compounds of the present invention, depending upon their structure, are capable of forming salts with pharmaceutically acceptable acids using procedures well known in the art. Examples of such acceptable acids include inorganic and organic acids, such as hydrochloric, hydrobromic, sulfuric, methanesulfonic, benzenesulfonic, p-toluenesulfonic and acetic acid. Preferred pharmaceutically acceptable salts of the compounds of Formula (I) include hydrochloride and hydrobromide salts. The compounds of Formula (I) which are preferred for their ability to inhibit 5-lipoxygenase pathway, as evidenced by their ability to inhibit 5-lipoxygenase pathway products, such as LTB₄, 5-HETE and /or LTC₄, include those listed in Table A below: It is known that some of the compounds of Formula (I) are useful for treating cyclooxygenase product-mediated disease states. It has now been discovered that all of the compounds of Formula (I) are also useful for treating disease states mediated by 5-lipoxygenase products by inhibiting the 5-lipoxygenase pathway. The discovery that the compounds of Formula (I) are dual inhibitors of the cyclooxygenase and 5-lipoxygenase pathways or sole inhibitors of the 5-lipoxygenase pathway is based on the effects of the compounds of Formula (I) on tissue inflammation in vivo and on the production of 5-lipoxygenase products by inflammatory cells in vitro in assays which are described in the Examples. In summary, such assays reveal that the compounds of Formula (I) display anti-inflammatory activity in arachidonic acid-induced inflammation in the mouse ear model. The cyclooxygenase inhibitor, indomethacin, did not reduce inflammation in this assay. These data, together with previous observations on the anti-edematous effects of the compounds of Formula (I) in inflammatory lesions caused by cyclooxygenase-generated products, reveal that the compounds of Formula (I) inhibit either just the 5-lipoxygenase pathway or both the 5-lipoxygenase and cyclooxygenase pathways of arachidonic acid metabolism. The 5-lipoxygenase pathway inhibitory action of the compounds of Formula (I) was confirmed by showing that they impaired the production of 5-lipoxygenase products such as leukotriene B₄ (di-HETE) and 5-HETE production by RBL-1 cells. The pathophysiological role of arachidonic acid metabolites has been the focus of recent intensive studies. In addition to the well-described phlogistic activity (i.e. general inflammatory activity) of prostaglandins, the more recent description of similar activity for eicosanoids has broadened the interest in these products as mediators of inflammation. The reported discovery of potent chemotactic and algesic activity for LTB₄, together with known LTC₄ and LTD₄-mediated increase in capillary permeability has led to their consideration as targets for pharmacological intervention in both the fluid and cellular phases of inflammatory diseases. The pharmacology of several inflammatory model systems has attested to the effectiveness of corticosteroids, known to inhibit the generation of both cyclooxygenase and lipoxygenase products, in reducing the cellular infiltration. These results, suggest that such dual inhibitors may effectively reduce both the fluid and cellular phases of the inflammatory response. Thus a dual inhibitor of arachidonic acid metabolism would be a more effective antiinflammatory agent than an inhibitor of cyclooxygenase only. Under optimal conditions, an agent with preferential lipoxygenase inhibitory activity may not share the ulcerogenic liability of cyclooxygenase inhibitors or the toxicity of corticosteroids. Recent clinical data also support the utility of inhibitors of the 5-lipoxygenase pathway of arachidonic acid metabolism in a variety of inflammatory diseases. These include rheumatoid arthritis, inflammatory bowel disease, psoriasis, gout, myocardial infarction, organ transplant rejection, tissue trauma, asthma, and inflammation reactions in the central nervous system such as multiple schlerosis. This invention relates to a pharmaceutical composition comprising an effective, 5-lipoxygenase product inhibiting amount of a compound of Formula (IA), or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier or diluent. As stated above, it will be apparent to one of skill in the art that all the compounds of Formula (IA) are within the scope of Formula (I). The compounds of Formula (I) are administered in conventional dosage forms prepared by combining a compound of Formula (I) ("active ingredient") or a salt thereof in an amount sufficient to produce activity with a standard pharmaceutical carrier according to conventional procedures. These procedures may involve mixing, granulating and compressing or dissolving the ingredients as appropriate to the desired preparation. The resulting pharmaceutical compositions containing an effective 5-lipoxygenase pathway inhibiting amount of a compound of Formula (IA) are also objectives of this invention. The pharmaceutical carrier employed may be, for example, either a solid or liquid. Exemplary of solid carriers are lactose, terra alba, sucrose, talc, gelatin, agar, pectin, acacia, magnesium stearate, stearic acid and the like. Exemplary of liquid carriers are syrup, peanut oil, olive oil, water and the like. Similarly, the carrier or diluent may include a time delay material well known to the art, such as glyceryl monostearate or glyceryl distearate alone or with a wax. A wide variety of pharmaceutical forms can be employed. Thus, if a solid carrier is used, the preparation can be tableted, placed in a hard gelatin capsule in powder or pellet form or in the form of a troche or lozenge. The amount of solid carrier will vary widely but preferably will be from about 50 mg to about 500 mg. If a liquid carrier is used, the preparation will be in the form of a syrup, emulsion, soft gelatin capsule, sterile injectable liquid such as an ampule or a nonaqueous liquid suspension. To obtain a stable water soluble dose form, a pharmaceutically acceptable acid addition salt, preferably hydrochloride or sulfate, of a compound of Formula (I) is dissolved in an aqueous solution of an organic or inorganic acid, such as a 0.3 M solution of succinic acid or preferably citric acid. In addition to sulfate and hydrochloride, methanesulfonate, phosphate and hydrobromide are exemplary of other water soluble salts. Preferably, each parenteral dosage unit will contain the active ingredient in an amount of from about 50 mg to about 500 mg. The compounds of Formula (I) may also be administered by inhalation. Appropriate dosage forms for such administration, such as an aerosol formulation or a metered dose inhaler, may be prepared by convention techniques. The preferred daily dose amount of a compound of Formula (I) administered by inhalation is from about l0 mg to about 200 mg per day. The compounds of Formula (I) may be administered topically to a mammal in need of the inhibition of the 5-lipoxygenase pathway of arachidonic acid metabolism. Thus, the compounds of Formula (I) may be administered topically in the treatment or prophylaxis of inflammation in an animal, including man and other mammals, and may be used in the relief or prophylaxis of 5-lipoxygenase pathway mediated diseases, such as rheumatoid arthritis, rheumatoid spondylitis, oestoarthritis, gouty arthritis and other arthritic conditions, inflamed joints, eczema, psoriasis or other inflammatory skin conditions such as sunburn; inflammatory eye conditions including conjunctivitis; pyresis, pain and other conditions associated with inflammation. The amount of a compound of Formula (I) (hereinafter referred to as the active ingredient) required for therapeutic effect on topical administration will, of course, vary with the compound chosen, the nature and severity of the inflammatory condition and the animal undergoing treatment, and is ultimately at the discretion of the physician. A suitable anti-inflammatory dose of an active ingredient is 1 µg to 500 mg of base for topical administration, the most preferred dosage being 1 µg to 1000 µg, for example, 5 to 25 µg; administered two or three times daily. By topical administration is meant non-systemic administration and includes the application of a compound of Formula (I) externally to the epidermis, to the buccal cavity and instillation of such a compound into the ear, eye and nose, and where the compound does not significantly enter the blood stream. By systemic administration is meant oral, intravenous, intraperitoneal and intramuscular administration. While it is possible for an active ingredient to be administered alone as the raw chemical, it is preferable to present it as a pharmaceutical formulation. The active ingredient may comprise, for topical administration, from 0.001% to 10% w/w, e.g. from 1% to 2% by weight of the formulation although it may comprise as much as 10% w/w but preferably not in excess of 5% w/w and more preferably from 0.1% to 1% w/w of the formulation. The topical formulations of the present invention both for veterinary and for human medical use, comprise an active ingredient together with one or more acceptable carrier(s) therefor and optionally any other therapeutic ingredient(s). The carrier(s) must be 'acceptable' in the sense of being compatible with the other ingredients of the formulation and not deleterious to the recipient thereof. Formulations suitable for topical administration include liquid or semi-liquid preparations suitable for penetration through the skin to the site of inflammation such as: liniments, lotions, creams, ointments or pastes, and drops suitable for administration to the eye, ear or nose. Drops according to the present invention may comprise sterile aqueous or oily solutions or suspensions and may be prepared by dissolving the active ingredient in a suitable aqueous solution of a bactericidal and/or fungicidal agent and/or any other suitable preservative, and preferably including a surface active agent. The resulting solution may then be clarified by filtration, transferred to a suitable container which is then sealed and sterilized by autoclaving or maintaining at 98-100°C for half an hour. Alternatively, the solution may be sterilized by filtration and transferred to the container by an aseptic technique. Examples of bactericidal and fungicidal agents suitable for inclusion in the drops are phenylmercuric nitrate or acetate (0.002%), benzalkonium chloride (0.01%) and chlorhexidine acetate (0.01%). Suitable solvents for the preparation of an oily solution include glycerol, diluted alcohol and propylene glycol. Lotions according to the present invention include those suitable for application to the skin or eye. An eye lotion may comprise a sterile aqueous solution optionally containing a bactericide and may be prepared by methods similar to those for the preparation of drops. Lotions or liniments for application to the skin may also include an agent to hasten drying and to cool the skin, such as an alcohol or acetone, and/or a moisturizer such as glycerol or an oil such as caster oil or arachis oil. Creams, ointments or pastes according to the present invention are semi-solid formulations of the active ingredient for external application. They may be made by mixing the active ingredient in finely-divided or powdered form, alone or in solution or suspension in an aqueous or non-aqueous fluid, with the aid of suitable machinery, with a greasy or non-greasy basis. The basis may comprise hydrocarbons such as hard, soft or liquid paraffin, glycerol, beeswax, a metallic soap; a mucilage; an oil or natural origin such as almond, corn, arachis, castor or olive oil; wool fat or its derivatives, or a fatty acid such as stearic or oleic acid together with an alcohol such as propylene glycol or macrogels. The formulation may incorporate any suitable surface active agent such as an anionic, cationic or non-ionic surfactant such as sorbitan esters or polyoxyethylene derivatives thereof. Suspending agents such as natural gums, cellulose derivatives or inorganic materials such as silicaceous silicas, and other ingredients such as lanolin, may also be included. This invention relates to a compound of Formula (I) in a medicament for use in treating a disease state mediated by the 5-lipoxygenase pathway in an animal in need thereof, including humans and other mammals, provided that such animal is in need of treatment of a 5-lipoxygenase pathway mediated disease other than, or in addition to, rheumatoid arthritis, by administering to such animal an effective, 5-lipoxygenase pathway inhibiting amount of a Formula (I) compound. By "treating" is meant either prophylactive or therapeutic therapy. By "mediated" is meant exacerbated or caused by. This invention also relates to compounds of Formula (IA) in a medicament to use in treating rheumatoid arthritis in an animal in need thereof, including humans and other mammals, by administering to such animal an effective, 5-lipoxygenase pathway inhibiting amount of a Formula (IA) compound. The Formula (I) compound is administered to an animal in need of inhibition of the 5-lipoxygenase pathway in an amount sufficient to inhibit the 5-lipoxygenase pathway. The Formula (IA) compound is administered to an animal in need of treatment of rheumatoid arthritis in an amount sufficient to inhibit the 5-lipoxygenase pathway. Such Formula (I) compound can be administered to such animal in a conventional dosage form prepared by combining the Formula (I) compound with a conventional pharmaceutically acceptable carrier or diluent according to known techniques. It will be recognized by one of skill in the art that the form and character of the pharmaceutically acceptable carrier or diluent is dictated by the amount of active ingredient with which it is to be combined, the route of administration and other well-known variables. The route of administration may be parenteral by inhalation or topical. The compounds of Formula (I) are either poorly active or inactive when administered orally. The term parenteral as used herein includes intravenous, intramuscular, subcutaneous, intranasal, intravaginal, intrarectal or intraperitoneal administration. The subcutaneous and intramuscular forms of parenteral administration are generally preferred. The daily dosage regimen will preferably be from about 50 mg to about 1000 mg per day. It will be recognized by one of skill in the art that the optimal quantity and spacing of individual dosages of the Formula (I) compound will be determined by the nature and extent of the condition being treated, the form, route and site of administration, and the particular animal being treated, and that such optimums can be determined by conventional techniques. It will also be appreciated by one of skill in the art that the optimal course of treatment, i.e., the number of doses of the Formula (I) compound given per day for a defined number of days, can be ascertained by those skilled in the art using conventional course of treatment determination tests. Without further elaboration, it is believed that one skilled in the art can, using the preceding description, utilize the present invention to its fullest extent. EXAMPLE 1 4,5-Bis(4-fluorophenyl)-2-cyanamido-imidazole or 4,5-Bis(4-fluorophenyl-2-amino-1-cyano-imidazole To a solution 15 g (0.048 mol) of 2-bromo-1,2-di-(4-fluorophenyl)-ethan-1-one in 80 ml of dry N,N-dimethylformamide was added 12.1 g. (0.144 mol) of cyanoguanidine with stirring. After 120 hours, the solution was poured into cold water and extracted into methylene chloride. The extract was washed with water, dried with magnesium sulfate and concentrated. The chilled concentrate deposited a solid which was filtered and recrystallized from acetonitrile to afford white crystals, melting point (mp) 197-199°C. Analyzed for C₁₆H₁₀F₂N₄; Calcd.: C, 64,86; H, 3.40; N, 18.91. Found: C, 64.90; H, 3.57; N, 18.71. Identification of which of the above-named isomers was obtained was not determined. EXAMPLE 2 1,5-Bis(4-methoxyphenyl)-2-cyanamido-imidazole or 4,5-Bis(4-methoxyphenyl)-2-amino-1-cyano-imidazole To a solution of 25 g (0.074 mol) of 2-bromoanisoin in 150 ml of dry N,N-dimethylformamide was added 18.75 g (0.223 mol) of cyanoguanidine with stirring. After 96 hours, the solution was poured into 500 ml of cold water. The mixture was made acidic with 6N hydrochloric acid and extracted with methylene chloride. The organic layer was washed with water, dried with magnesium sulfate and concentrated to give a yellow solid. Recrystallation from methanol-water gave white crystals, melting point 192-199°C. Analyzed for C₁₈H₁₆N₄O₂; Calcd.: C, 67.49; H, 5.03; N, 17.49. Found: C, 67.44; H, 4.79; N, 17.43. Identification of which of the above-named isomers was obtained was not determined. EXAMPLE 3 4-(4-pyridyl)-5(phenyl)-2-cyanoamido-imidazole or 4(4-[pyridyl or phenyl])-5(phenyl or pyridyl)-2-amino-1-cyano-imidazole A solution of 4-phenyl-4-pyridylmethyl ketone (5.0 g, 25 mmol) in 100 ml of methylenechloride is treated with an equimolar quantity of bromine in 10 ml of methylenechloride. Immediate discharge of the coloration is observed. To a solution of 12.5 g (0.048 mol) of the resulting 4-[2-(α-bromo-phenacyl)]pyridine in 80 ml of dry N,N-dimethylformamide is added 12.5 g (.048 mol) of cyanoguanidine with stirring. After about 120 hours, the solution is poured into cold water and is extracted into methylenechloride. The extract is washed with water, is dried with magnesium sulfate and is concentrated in vacuo . The residue is recrystallized from acetonitrile to afford the crystalline product. This resulting product is one or a mixture of the above-named isomers. UTILITY EXAMPLES In the following Examples male Balb/c mice (20-28 g) were used. All mice were obtained from Charles River Breeding Laboratories, Kingston, NY, U.S.A. Within a single experiment, mice were sex and age matched. In the following assays, reagents used were employed as follows: The compounds of Formula (I), indomethacin, naproxen, and ibuprofen were each used as the free base. The compounds were homogenized in 0.5% tragacanth. Compounds were administered by gavage at the indicated dose in a final volume of 10 ml/kg. The compounds of Formula (I) were solubilized in dimethylacetamide and diluted with olive oil for subcutaneous administration. For in vitro experiments, compounds were dissolved at appropriate concentrations in ethanol (final concentration less than 1.0%) and then diluted to final concentrations using the buffers indicated in the text. I. METHODS Arachidonic Acid-Induced Mouse Ear Inflammation Arachidonic acid in acetone (2 mg/20 µl) was applied to the inner surface of the left ear. The thickness of both ears was then measured with a dial micrometer one hour after treatment, and the data were expressed as the change in thickness (10⁻³ cm) between treated and untreated ears. Test compounds were given orally in 0.5% tragacanth at the times indicated in the text prior to the topical application of arachidonic acid. Parenteral administration of compound was accomplished by subcutaneous injection of solution as indicated. Assay of 5-Lipoxygenase and Cyclooxygenase Activities The activities of these enzymes in extracts of RBL-1 cells were assayed. RBL-1 cells were obtained from the American Type Culture Collection (#CRL 1378) and were grown at 37°C (5% CO₂ in air) in spinner culture in minimal essential medium supplemented with 10% heat inactivated fetal calf serum. Harvested cells were washed with 50 mM sodium phosphate buffer, pH 7.0, containing l mM ethylenediaminetetraacetic acid and 0.l% gelatin, resuspended in fresh buffer (5 × 10⁷ cells/ml) and disrupted by nitrogen cavitation using the Parr bomb at 51 atm. for l0 minutes. The broken cell extract was then centrifuged at 10,000 × g for 60 minutes. Aliquots (0.25 mls) of the supernatant were preincubated with or without drugs for 10 minutes, after which 10 µl of calcium chloride (2 mM) of 2.5 mM arachidonic acid-1-¹⁴C (final concentration was 25 M; specific activity 20,000 dpm/nmole) was added. After incubation for 5 minutes at 5°C, the reaction was terminated by addition of 2 volumes (0.5 ml) ice cold acetone and the sample was allowed to deproteinize on ice for 10 minutes prior to centrifugation at 1,000 × g for 10 minutes. The deproteinized supernatant was adjusted to pH 3.5 with 2N formic acid and extracted with 2 volumes of ice cold ethyl acetate. The extracted samples were dried under argon, redissolved in ethyl acetate and applied to Whatman LK5D thin layer chromatography (TLC) plates, available from Whatman in Naidstone, England, which were developed using the A-9 solvent system [organic phase of ethyl acetate: 2,2,5-trimethylpentane:acetic acid: water (110:50:20:10)]. Arachidonic acid, 5-HETE, LTB₄ and PGD₂ were quantified with a Berthold LB 2832 autoscanner available from Berthold Analytical Inc., Nashua, NH, U.S.A. Drug-induced effects on enzyme activities are described as the concentration of drug causing a 50% inhibition of metabolite synthesis (IC₅₀). LTC-4 Production by Human Monocytes One of the compounds of Formula (I), i.e., Compound Number 8 from Table I, was evaluated for its ability to inhibit the production of LTC₄ by human monocytes according to the following protocol. Human monocytes were prepared from whole blood supplied by the American Red Cross. The blood was fractionated by a two-step procedure employing sedimentation on Ficoll gel available from Sigma Chemical Co., St. Louis, MO, U.S.A. followed by sedimentation on Percoll gel available from Pharmacia of Upsala, Sweden. The mononuclear cell fraction recovered was composed of 80-90% monocytes with the remainder of the cells being predominant lymphocytes. The monocytes were plated at 1 × 10⁶ cells per well in a Costar 24 well tissue culture plat available from Costar in Cambridge, MA, U.S.A., and allowed to adhere for one hour at 37°C. Non-adherent cells were removed by washing. The cells were stimulated with 1 M of A23l87 calcium ionophore available from Sigma Chemical Co., St. Louis, MO, U.S.A. for 3 hours at 37°C to induce LTC-4 production when drugs were evaluated. They were added to the cells 30 minutes prior to the A23187. Supernatants were collected, clarified by centrifugation and store frozed at -20°C until assay. The LTC-4 content was determined by using a New England Nuclear Leukotriene C-4 (³H) RIA Kit available from DuPont of Wilmington, DE, U.S.A. as per instructions. II. RESULTS The Effect of Compounds of Formula (I) on Arachidonic Acid-induced Inflammation Elucidation of the antiinflammatory activity of compounds of Formula (I) was achieved in models of arachidonic acid-induced edema in mice and rats. The mouse ear edematous response to arachidonic acid has been shown to be sensitive to agents that inhibit both lipoxygenase- and cyclooxygenase-generated mediators or that selectively inhibit lipoxygenase, but not cyclooxygenase, enzyme activity. Compounds of Formula (I) produced marked inhibition of the edematous response normally seen 1 hour after the application of 2 mg of arachidonic acid to the ear (Table I). The cyclooxygenase inhibitors, indomethacin (10 mg/kg, p.o.), ibuprofen (250 mg/kg, p.o.) and naproxen (100 mg/kg, p.o.) did not exhibit detectable antiinflammatory activity in this assay, despite use at near maximally tolerated doses. Collectively, these findings indicate that compounds of Formula (I) are, in general, potent inhibitors of the inflammatory response to arachidonic acid. The Effect of Compounds of Formula (I) on Arachidonic Acid Metabolism Experiments using a soluble extract preparation of RBL-1 cells containing only lipoxygenase activity confirmed the inhibitory effects of compounds of Formula (I) on LTB₄ production (Table I) and 5-HETE production (Table I). The data in Table I shows that compounds of Formula (I) are able to inhibit the 5-lipoxygenase pathway since they inhibit production of LTB₄, a 5-lipoxygenase pathway product. Indomethacin at concentrations up to 10⁻⁴M was inactive. The data in Table I also shows that compounds of Formula (I) are able to inhibit the 5-lipoxygenase pathway since they inhibit production of 5-HETE, a 5-lipoxygenase pathway product. LTC₄ Inhibition Assay As shown in Table I, a compound of Formula (I) was efficacious in inhibiting LTC₄ production, a 5-lipoxygenase pathway product, by human monocytes. These data confirm the ability of compounds of Formula (I) to inhibit the 5-lipoxygenase pathway. As seen in Table I not all compounds of Formula (I) significantly inhibited arachidonic acid-induced ear swelling, but such compounds did significantly inhibit the production of LTB₄ by RBL-1 high speed supernatant and/or the production of 5-HETE indicating that such compounds are indeed inhibitors of the 5-lipoxygenase pathway. EXAMPLE A - INJECTABLE PARENTERAL COMPOSITION A pharmaceutical composition of this invention in a form suitable for administration by injection is prepared by stirring 1.5% by weight of a compound of Formula (IA) in 10% by volume propylene glycol and water. The solution is sterilized by filtration. EXAMPLE B - OINTMENT COMPOSITION Compound of Formula (IA) 1.0 g White soft paraffin to 100.0 g The compound of Formula (IA) is dispersed in a small volume of the vehicle. This dispersion is gradually incorporated into the bulk to produce a smooth, homogenous product which is filled into collapsible metal tubes. EXAMPLE C - TOPICAL CREAM COMPOSITION Compound of Formula (IA) 1.0 g Polawax GP 200 20.0 g Lanolin Anhydrous 2.0 g White Beeswax 2.5 g Methyl hydroxybenzoate 0.1 g Distilled Water to 100.0 g The polawax, beeswax and lanolin are heated together at 60°C and a solution of methyl hydroxybenzoate is added. Homogenization is achieved and then using high speed stirring temperature is allowed to fall to 50°C. The compound of Formula (IA) is added and dispersed throughout, and the composition is allowed to cool with slow speed stirring. EXAMPLE D - TOPICAL LOTION COMPOSITION Compound of Formula (1A) 110 g Sorbitan Monolaurate 0.6 g Polysorbate 20 0.6 g Cetostearyl Alcohol 1.2g Glycerin 6.0 g Methyl Hydroxybenzoate 0.2 g Purified Water B.P. to 100.00 ml The methyl hydroxybenzoate and glycerin are dissolved in 70 ml of the water at 75°. The sorbitan monolaurate, polysorbate 20 and cetostearyl alcohol are melted together at 75°C and added to the aqueous solution. The resulting emulsion is homogenized, allowed to cool with continuous stirring and the compound of Formula (IA) is added as a suspension in the remaining water. The whole suspension is stirred until homogenous. EXAMPLE E - EYE DROP COMPOSITION Compound of Formula (IA) 0.5 g Methyl Hydroxybenzoate 0.01 g Propyl Hydroxybenzoate 0.04 g Purified Water B.P. to 100.00 ml The methyl and propyl hydroxybenzoates are dissolved in 70 ml purified water at 75°C and the resulting solution is allowed to cool. The compound of Formula (IA) is then added, and the solution is made up to 100 ml with purified water. The solution is sterilized by filtration through a membrane filter (0.22 mu m pore size) and packed aseptically into suitable sterile containers. EXAMPLE F - COMPOSITION FOR ADMINISTRATION BY INHALATION For an aerosol container with a capacity of 15-20 ml: Mix 10 mg of a compound of Formula (IA) with 0.1-0.2% of a lubricating agent, such as Span 85 or oleic acid, and disperse such mixture in a propellant, such as freon, preferably a combination of freon 114 and freon 12, and put into an appropriate aerosol container adopted for either intranasal or oral inhalation administration. EXAMPLE G - COMPOSITION FOR ADMINISTRATION BY INHALATION For an aerosol container with a capacity of 15-20 ml: Dissolve 10 mg of a compound of Formula (IA) in ethanol (6-8 ml) and 0.1-.2% of a lubricating agent, such as Span 85 or oleic acid, and disperse such in a propellant, such as freon, preferably a combination of freon 114 and freon 12, and put into an appropriate aerosol container adapted for either intranasal or oral inhalation administration.

Claims: Claims for the following Contracting States : BE, CH, DE, FR, GB, IT, LI, LU, NL, SE A compound of the formula (IA) wherein: X¹ is NHCN or NH₂; R¹ and R are independently selected from pyridyl or monosubstituted phenyl wherein said substituent is selected from halo or C₁₋₄ alkoxy; and Y¹ is H or CN provided that when X¹ is NH₂, Y¹ is CN and when X¹ is NHCN, Y¹ is H; or a pharmaceutically acceptable salt thereof. The compound of Claim 1 wherein Y¹ is H, X¹ is NHCN and R and R¹ are both 4-methoxyphenyl. The compound of Claim 1 wherein Y¹ is H, X¹ is NHCN and R and R¹ are both 4-fluorophenyl; or wherein Y¹ is CN, X¹ is NH₂ and R and R¹ are both 4-fluorophenyl. The compounds of Claim 1 wherein a) R and R¹ are both 4-fluorophenyl, or b) R and R¹ are both 4-methoxyphenyl, A pharmaceutical composition comprising an effective, non-toxic 5-lipoxygenase pathway inhibiting amount of a compound as defined in any one of claims 1 to 3, and a pharmaceutically acceptable carrier or diluent. The composition of Claim 5 wherein the composition is in a dosage unit form adapted for parenteral administration, topical administration, or administration by inhalation. A compound as defined in any one of Claims 1 to 3 for use in the treatment of rheumatoid arthritis. A compound as defined in any one of claims 1 to 3 for use in the treatment of a 5-lipoxygenase mediated disease. The use of a compound in the preparation of a medicament for the treatment of a 5-lipoxygenase pathway mediated disease other than or in addition to rheumatoid arthritis or any other cyclooxygenase mediated disease state, said compound being of the formula (I) wherein: X is SH, OH, H, S(O) n R², NHCN, NH₂, polyhalo C₁₋₄ alkyl, or 4-halophenyl; n is 0, 1 or 2; R² is selected from H, C₁₋₆ alkyl, mono- or polyhalo C₁₋₄ alkyl, or C₁₋₄ alkylamino; R and R¹ are independently selected from pyridyl or substituted phenyl wherein said substituent is selected from halo, C₁₋₄ alkoxy, or C₁₋₄ alkylthio; provided that when R and/or R¹ are pyridyl, R² is other than C₁₋₆ alkyl, tetrahaloethyl or C₁₋₄ perhaloalkyl; and Y is H, CN, or C₁₋₄ alkyl; provided that when X is NH₂, Y is CN and when X is NHCN, Y is H; or a pharmaceutically acceptable salt thereof. A process for the preparation of a compound of Claim 1 comprising reacting cyanoguanidine with a compound of formula (II) wherein R and R¹ are the same or different and are pyridyl or monosubstituted phenyl wherein said substituent is selected from halo or C₁₋₄ alkoxy, and X is bromo or chloro. Claims for the following Contracting States : AT, ES, GR A process for the preparation of a compound of formula (IA) wherein: X¹ is NHCN or NH₂; R¹ and R are independently selected from pyridyl or monosubstituted phenyl wherein said substituent is selected from halo or C₁₋₄ alkoxy; and Y¹ is H or CN Provided that when X¹ is NH₂, Y¹ is CN and when X¹ is NHCN, Y¹ is H; or a pharmaceutically acceptable salt thereof comprising reacting a compound of formula II wherein R and R¹ are the same or different and are pyridyl or monosubstituted phenyl wherein the substituent is selected from halo or C₁₋₄ alkoxy, and X is bromo or chloro, with cyanoguanidine. The process of Claim 1 wherein the ratio of the compound of formula (II) to cyanoguanidine reacted is 1:3. A process according to either of claims 1 or 2 wherein the reaction is conducted in N,N-dimethyl-formamide. A process according to any one of claims 1-3 wherein the reaction is conducted at approximately ambient temperature. A process according to any one of claims 1 to 4 wherein R and R¹ are both 4-methoxyphenyl. A process according to any one of claims 1 to 4 wherein R and R¹ are both 4-fluorophenyl. A process for the preparation of a pharmaceutical composition containing a compound as defined in claim 1, which process comprises bringing the compound into association with a pharmaceutically acceptable carrier.

Inventors: BENDER, PAUL ELLIOT, GRISWOLD, DON EDGAR, HANNA, NABIL, SARAU, HENRY MARTIN
Applicants: SMITHKLINE BEECHAM CORPORATION
Application year: 1986
Main classification: C07D233
IPC codes: C07D401, C07D233