NOVEL IMIDAZOLE COMPOUNDS, PROCESS FOR PREPARATION THEREOF ANTIFUNGAL AGENT AND MILDEWPROOF AGENT

Abstract: Compound of formula (I) wherein A₁ is thien-3-yl or 4-chlorophenyl and A₂ is 2,4-dichlorophenyl, 2-chlorothien-3-yl or 2-chloro-5-bromothien-3yl, with the proviso that at least one of A₁ and A₂ stands for a thien-3-yl or halogen-substituted thien-3-yl group, are effective as a therapeutic antifungal agent or mildewproofing agent.

Description: Background of the Invention (1) Field of the Invention The present invention relates to a novel imidazole compound and a process for the preparation thereof. Furthermore, the present invention relates to an antifungal agent and a mildewproofing agent, which comprise this novel imidazole compound. More particularly, the present invention relates to an imidazole compound which is valuable as a therapeutic antifungal agent. (2) Description of the Related Art It is known that certain imidazole compounds have a fungicidal action. For example, Japanese Patent Publication No. 16479/68 discloses 1-hydroxy-2-undecyl-­ 3-methylimidazolium-p-toluene-sulfonate, 1-benzyl-2-­ undecyl-3-methylimidazolium methylsulfate and 1-dodecyl-­ 2-ethyl-3-benzylimidazolium chloride as fungicidal agents. Furthermore, the specification of U.S. Patent No. 4,577,032 discloses 1-benzyldibromomethyl-2-­ methylimidazole. The compound of the present invention has a much broader antimicrobial spectrum than those of these known compounds. Summary of the Invention The imidazole compound of the present invention is represented by the following general formula (1): wherein A1 stands for a thien-3-yl or 4-chlorophenyl group and A₂ stands for a 2,4-dichlorophenyl, 2-chlorothien-3-yl or 2-chloro-5-bromothien-3-yl group, with the proviso that at least one of A₁ and A₂ stands for a thien-3-yl or halogen-substituted thien-3-yl group. This compounds represented by the general formula 1) can be prepared by reacting an imidazolylethanone compound represented by the following general formula 2): wherein A₁ is as defined above, with an aldehyde compound represented by the following general formula (3): A₂-CHO (3) wherein A₂ is as defined above. Among compounds represented by the general formula (1), the following imidazole compounds are especially preferred: 1-(thien-3-yl)-2-(1H-imidazolyl)-3-(2,4-­ dichlorophenyl)-2-propen-1-one of the following formula: 1-(thien-3-yl)-2-(1H-imidazolyl)-3-(2-chlorothien-­ 3-yl)-2-propen-1-one of the following formula: 1-(4-chlorophenyl)-2-(1H-imidazolyl)-3-(2-­ chlorothien-3-yl)-2-propen-1-one of the following formula: 1-(4-chlorophenyl)-2-(1H-imidazolyl)-3-(2-chloro-5-­ bromothien-3-yl)-2-propen-1-one of the following formula: Detailed Description of the Invention The imidazole compound of the present invention can be prepared by refluxing 1 mole of the imidazolylethanone compound of the formula (2) and 1 to 2 moles of the aldehyde compound of the formula (3) in a solvent such as benzene in the presence of piperidine for 1 to 10 hours. After completion of the reaction, the reaction liquid is concentrated and the reaction product is eluted with a solvent such as chloroform or chloroform/methyl alcohol by the silica gel chromatography, and the eluate is crystallized by using a solvent such as isopropyl ether or n-hexane and recrystallized from a solvent such as ethyl acetate or ethyl acetate/n-hexane. Thus, the intended imidazole compound can be obtained. The compounds of the present invention are characterized in that they are in the form of white or yellow crystals, neutral or weakly acidic, hardly soluble in water and soluble in ethyl acetate, n-hexane and dimethyl sulfoxide. These compounds have a relatively broad antimicrobial spectrum and are valuable as fungicidal agents, and they are particularly effective when used as antifungal agents or mildewproofing agents. The present invention will now be described in detail with reference to the following examples that by no means limit the scope of the invention. Example 1 Preparation of 1-(thien-3-yl)-2-(1H-imidazolyl)-3-­ (2,4-dichlorophenyl)-2-propen-1-one. In the presence of piperidine, 1.37 g of 1-(thien-­ 3-yl)-2-(1H-imidazolyl)ethane and 1.87 g of 2,4-­ dichlorobenzaldehyde were refluxed in benzene for 7 hours. After completion of the reaction, the reaction liquid was concentrated and the reaction product was eluted with chloroform by the silica gel chromatography, and the eluate was crystallized and precipitated by using isopropyl ether and the crystals were recrystallized from ethyl acetate/isopropyl ether to obtain 0.64 g of a white crystal having a melting point of 102 to 103°C. From the results of the analysis, it was confirmed that the product was 1-(thien-3-yl)-2-(1H-imidazolyl)-3-­ (2,4-dichlorophenyl)-2-propen-1-one represented by the following structural formula, and the yield was 26%. Structural Formula: Elementary Analysis Values (%): Found values: C = 54.75, H = 2.66, N = 7.54 Calculated values: C = 55.04, H = 2.89, N = 8.02 Nuclear Magnetic Resonance Analysis (chloroform-d, ppm): 7.77 (1H, s, 2-position of imidazole), 7.73 (1H, m, 2-position of thiophene), 7.28-7.58 (4H, m, 4,5-­ positions of thiophene, C=CH-, 3-position of 2,4-dichlorobenzene), 7.18 (2H, s, 4,5-positions of imidazole), 6.91 (1H, m, 5-position of 2,4-­ dichlorobenzene), 6.61 (1H, d, 6-position of 2,4-dichlorobenzene) Example 2 Preparation of 1-(thien-3-yl)-2-(1H-imidazolyl)-3-­ (2-chlorothien-3-yl)-2-propen-1-one. In the presence of piperidine, 1.25 g of 1-(thien-­ 3-yl)-2-(1H-imidazolyl)ethanone and 0.95 g of 2-chloro-­ 3-thiophene aldehyde were refluxed in benzene for 2.5 hours. After completion of the reaction, the reaction liquid was concentrated and the reaction product was eluted with chloroform/methanol by the silica gel chromatography. The eluate was crystallized by using n-­ hexane and the crystals were recrystallized from ethyl acetate/n-hexane to obtain 0.56 g of a light brown crystal having a melting point of 116 to 118°C. From the results of the analysis, it was confirmed that the product was 1-(thien-3-yl)-2-(1H-imidazolyl)-3-­ (2-chlorothien-3-yl)-2-propen-1-one represented by the following structural formula, and the yield was 27%. Structural Formula: Elementary Analysis Values (%): Found values: C = 52.12, H = 2.68, N = 8.29 Calculated values: C = 52.41, H = 2.83, N = 8.73 Nuclear Magnetic Resonance Analysis (chloroform-d/dimethylsulfoxide-d6, ppm): 7.72-8.05 (3H, m, 2-position of thiophene, C=CH-, 2-position of imidazole), 7.48 (2H, m, 4,5-­ positions of thiophene), 7.19 (2H, s, 4,5-­ positions of imidazole), 7.10 (1H, d, 5-position of 2-chlorothiophene), 5.79 (1H, d, 4-position of 2-chlorothiophene) Example 3 Preparation of 1-(4-chlorophenyl)-2-(1H-­ imidazolyl)-3-(2-chlorothien-3-yl)-2-propen-1-one. In the presence of piperidine, 3.00 g of 1-(4-­ chlorophenyl)-2-(1H-imidazolyl)ethanone and 2.00 g of 2-chloro-3-thiophene aldehyde were refluxed in benzene for 8 hours. The reaction product was treated in the same manner as described in Example 2 to obtain 1.60 g of a light yellow crystal having a melting point of 137 to 139°C. From the results of the analysis, it was confirmed that the product was 1-(4-chlorophenyl)-2-(1H-­ imidazolyl)-3-(2-chlorothien-3-yl)-2-propen-1-one having the following structural formula, and the yield was 34%. Structural Formula: Elementary Analysis Values (%): Found values: C = 55.01, H = 2.79, N = 7.88 Calculated values: C = 55.04, H = 2.89, N = 8.02 Nuclear Magnetic Resonance Analysis (chloroform-d, ppm): 7.55 (1H, s, 2-position of imidazole), 7.51 (1H, s, C=CH-), 7.35-7.83 (4H, each d, 3,5-positions of 4-chlorobenzene, 2,6-positions of 4-­ chlorobenzene), 7.26 and 6.95 (1H, s, 4- or 5-position of thiophene), 5.83 (1H, d, 4-position of thiophene) Example 4 Preparation of 1-(4-chlorophenyl)-2-(1H-­ imidazolyl)-3-(2-chloro-5-bromothien-3-yl)-2-propen-1-­ one. In the presence of piperidine, 1.96 g of 1-(4-­ chlorophenyl)-2-(1H-imidazolyl)ethanone and 2.00 g of 2-­ chloro-5-bromo-3-thiophene aldehyde were refluxed in benzene for 8.5 hours. The reaction product was treated in the same manner as described in Example 2 to obtain 1.60 g of a light yellow crystal having a melting point of 155 to 157°C. From the results of the analysis, it was confirmed that the product was 1-(4-chlorophenyl)-2-(1H-­ imidazolyl)-3-(2-chloro-5-bromothien-3-yl)-2-propen-1-­ one represented by the following structural formula, and the yield was 42%. Structural Formula: Elementary Analysis Values (%): Found values: C = 45.80, H = 2.25, N = 6.36 Calculated values: C = 44.88, H = 2.12, N = 6.54 Nuclear Magnetic Resonance Analysis (chloroform-d, ppm): 7.36-7.76 (6H, m, 2-position of imidazole, aromatic), 7.29 and 6.25 (2H, each, s, 4,5-positions of imidazole), 5.73 (1H, d, 4-position of thiophene) Example 5 With respect to the compounds obtained in the foregoing examples, the minimum growth inhibiting concentrations to pathogenic bacterial were measured. The obtained results are shown in Table 1. The unit of each value in Table 1 is µg/ml. The used pathogenic bacteria were Candida albicans , Trichophyton rubrum , Trichophyton mentagrophytes , Trichophyton tonsurans and Microsporum gypsum . Culturing was conducted in Sabouraud's agar culture medium at 25°C. The growth of the bacterium was checked at intervals of 24 hours after inoculation. The minimum concentration at which no colony was formed was measured as the minimum inhibitory concentration after the passage of 7 days. Compound of Present Invention Candida albicans Trichophyton rubrum Trichophyton mentagrophytes Trichophyton tonsurans Microsporum gypseum Example 1 6.25 < 0.39 < 0.39 < 0.39 0.39 Example 2 25 1.56 3.13 3.13 12.5 Example 3 12.5 0.78 3.13 1.56 6.25 Example 4 12.5 < 0.39 < 0.39 0.78 12.5

Claims: 1. A compound of formula (I): wherein A₁ is a thien-3-yl or 4-chlorophenyl and A² is 2,4-dichlorophenyl, 2-chlorothien-3-yl or 2-chloro-5-bromothien-3-yl with the proviso that at least one of A₁ and A₂ stands for a thien-3-yl or halogen-substituted thien-3-yl group. 2. 1-(Thien-3-yl)-2-(1H-imidazolyl)-3-(2,4-­ dichlorophenyl)-2-propen-1-one. 3. 1-(Thien-3-yl)-2-(1H-imidazolyl)-3-(2-­ chlorothien-3-yl)-2-propen-1-one. 4. 1-(4-Chlorophenyl)-2-(1H-imidazolyl)-3-(2-­ chlorothien-3-yl)-2-propen-1-one. 5. 1-(4-Chlorophenyl)-2-(1H-imidazolyl)-3-(2-­ chloro-5-bromothien-3-yl)-2-propen-1-one. 6. A process for preparing a compound of formula (1) according to claim 1 which comprises reacting an imidazolylethanone of formula (II) wherein A₁ is a defined in claim 1 with an aldehyde of formula (III) A₂-CHO (III) wherein A₂ is as defined in claim 1. 7. An antifugal or mildewproofing agent comprising a compound of formula (I) according to any one of claims 1 to 5. 8. An agent according to claim 7 further comprising a carrier of diluent. 9. Use of a compound of formula (I) according to any one of claims 1 to 5 as a mildewproofing agent or in the manufacture of a medicament for use in a method for treatment of the human or animal body by therapy for a fungal infection. 10. A compound of formula (I) according to one of claims 1 to 5 for use in a method for treatment of the human or animal body by therapy.

Inventors: AKITA, TADASHI, FUJITA, TAKAYUKI, IWASAKI, YOSHIYA, YABE, HIROKO
Applicants: SHIKOKU CHEMICALS CORPORATION
Application year: 1988
Main classification: C07D409
IPC codes: C07D521, A61P31, A01N43, C07D409, A61K31