Benzothiazole derivatives

Abstract: The object of the present invention is to provide novel benzothiazole derivatives and pharmaceutically acceptable salts thereof, which have a lipid lowering activity and are useful as a medicine. The compounds of the present invention and pharmaceutically acceptable salts thereof are represented by the following formula (I): wherein R 1 is halogen, alkyl, trifluoromethyl, acetamide or -OX 1 ; X 1 is hydrogen, alkyl or acyl; R 2 is hydrogen, halogen, alkyl, hydroxyalkyl, trifluoromethyl, nitro, amino which may be substituted with alkyl or acyl, carboxy which may be esterified with alkyl, or -OX 2 ; X 2 is hydrogen, alkyl, acyl, carboxyalkyl which may be esterified with alkyl; or n is an integer from 1 to 3 which means a number of substituent R 2 ; and plural R 2 may be the same or different when n is 2 or 3; with the proviso that R 1 is a group other than chloride when R 2 is hydrogen. The benzothiazole derivatives of the present invention have excellent pharmacological activities which significantly decrease cholesterol, triglyceride and low-density lipoprotein in blood. Therefore, they are novel compounds which are very useful as medicines such as a remedy for hyperlipemia.

Description: The present invention relates to novel benzothiazole derivatives and pharmaceutically acceptable salts thereof, which are useful as a medicine. Lipids such as cholesterol, triglyceride, phospholipid and free fatty acid are present in blood. Many kinds of diseases are caused by the abnormal increase or unbalance of such lipids. For instance, hyperlipemia is not only the direct cause of arteriosclerosis but also causes various symptoms such as abnormal glucometabolism, ischemic heart diseases, and the like. EP-A-030 632 provides benzothiazole derivatives of the general formula wherein R 1 is H or CH 3 , R 2 is phenyl, tolyl, xylyl or pyridyl, R 3 is OH, alkoxy having 1 to 4 carbon atoms or -NHCH 2 CH 2 OH, and R 4 is H, Cl, Br, OH or alkoxy having 1 to 4 carbon atoms. These compounds are stated to show a lowering effect on lipids. JP-A-53 071071 discloses alpha-phenoxyacetic acid derivatives of benzothiazole which are potentially useful as cholesterol-and lipid-lowering agents. Thus, the present inventors have conducted a study concerning a novel compound having a good lipid lowering activity. As a result, they have found that the novel benzothiazole derivatives of the present invention have an excellent pharmacological activity whereby the present invention has been achieved. The object of the present invention is to provide novel benzothiazole derivatives and pharmaceutically acceptable salts thereof, which have a lipid lowering activity and are useful as a medicine. The compounds of the present invention and pharmaceutically acceptable salts thereof are represented by the following formula (I): wherein R 1 is halogen, alkyl, trifluoromethyl, acetamide or -OX 1 ; X 1 is hydrogen, alkyl or acyl; R 2 is hydrogen, halogen, alkyl, hydroxyalkyl, trifluoromethyl, nitro, amino which may be substituted with alkyl or acyl, carboxy which may be esterified with alkyl, or -OX 2 ; X 2 is hydrogen, alkyl, acyl or carboxyalkyl which may be esterified with alkyl; or n is an integer from 1 to 3 which means a number of substituent R 2 ; and plural R 2 may be the same or different when n is 2 or 3; with the proviso that R 1 is a group other than chloride when R 2 is hydrogen. In the above-mentioned general formula (I), R 1 is halogen such as fluorine, chlorine, bromine and iodine; a linear or branched alkyl having 1 to 6 carbon atoms such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, t-butyl, pentyl, isopentyl, neopentyl, hexyl and dimethylbutyl; trifluoromethyl; actamide; or -OX 1 : X 1 is hydrogen; halogen such as fluorine, chlorine, bromine and iodine; a linear or branched alkyl having 1 to 6 carbon atoms such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, t-butyl, pentyl, isopentyl, neopentyl, hexyl and dimethylbutyl; or a liner or branched acyl having 1 to 6 carbon atoms such as formyl, acetyl, propionyl, butyryl, isobutyryl, valeryl, isovaleryl, pivaloyl, hexanoyl. R 2 is hydrogen; halogen such as fluorine, chlorine, bromine and iodine; a linear or branched alkyl having 1 to 6 carbon atoms such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, t-butyl, pentyl, isopentyl, neopentyl, hexyl and dimethylbutyl; a linear or branched hydroxyalkyl wherein alkyl has 1 to 6 carbon atoms such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, t-butyl, pentyl, isopentyl, neopentyl, hexyl and dimethylbutyl; trifluoromethyl; nitro; amino which may be substituted with 1 or 2 of linear or branched alkyls having 1 to 6 carbon atoms such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, t-butyl, pentyl, isopentyl, neopentyl, hexyl and dimethylbutyl or with 1 or 2 of linear or branched acyls having 1 to 6 carbon atoms such as formyl, acetyl, propionyl, butyryl, isobutyryl, valeryl, isovaleryl, pivaloyl, hexanoyl; carboxy which may be esterified with a linear or branched alkyl having 1 to 6 carbon atoms such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, t-butyl, pentyl, isopentyl, neopentyl, hexyl and dimethylbutyl; or - OX 2 : X 2 is hydrogen; halogen such as fluorine, chlorine, bromine and iodine; a linear or branched alkyl having 1 to 6 carbon atoms such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, t-butyl, pentyl, isopentyl, neopentyl, hexyl and dimethylbutyl; a linear or branched acyl having 1 to 6 carbon atoms such as formyl, acetyl, propionyl, butyryl, isobutyryl, valeryl, isovaleryl, pivaloyl, hexanoyl; or carboxy-alkyl(C 1-6 ) which may be esterified with a linear or branched alkyl having 1 to 6 carbon atoms such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, t-butyl, pentyl, isopentyl, neopentyl, hexyl and dimethylbutyl. The compounds of the present invention maybe, for example, produced in accordance with the following methods. A benzothiazole having a substituent corresponding to R 1 is treated with a base such as n-butyllithium, t-butyllithium or lithium diisopropylamide at a low temperature. The resulting product is reacted with a compound such as benzoic ester, benzoyl chloride, benzamide or benzonitrile, which has a substituent corresponding to R 2 , to give a R 1 -2-(R 2 -benzoyl)benzothiazole derivative. Also, the benzothiazole derivatives of the present invention maybe produced as follows. A benzothiazole having a substituent corresponding to R 1 and a benzaldehyde having a substituent corresponding to R 2 are dissolved in the mixture of water and acetic acid containing conc. sulfric acid. Then, to the reaction mixture, a solution of a reagent producing acyl radicals, such as cerium sulfate, chronium sulfate, manganese sulfate, copper sulfate or iron sulfate, and t-butylhydroperoxide are simultaneously added to afford said benzothiazole derivative. In the case of producing the benzothiazole derivative of the present invention wherein R 1 or R 2 is hydroxy, a material compound having a hydroxy-protecting group such as (2-methoxyethoxy)methyl, benzyl or acetyl is used and reacted as mentioned above, and then the protecting group is removed to produce the intended benzothiazole derivative. To produce the benzothiazole derivative wherein R 1 is -OX 1 or R 2 is -OX 2 , such benzothiazole derivative maybe produced by a conventional acylation of hydroxy group, for example, a condensation reaction between the above benzothiazole derivative wherein R 1 or R 2 is hydroxy and carbonic anhydride such as acetic anhydride or halogenated compound such as acetyl chloride, or a reaction of carboxylic acid and a dehydrating-condensing agent such as dicyclohexylcarbodiimide (DCC). And to produce the benzothiazole derivative wherein R 2 is carboxy or X 2 is carboxyalkyl, such benzothiazole derivative maybe produced by hydrolysis of its ester form. The novel benzothiazole derivatives of the present invention include the pharmaceutically acceptable salts of the compounds represented by the above-given general formula (I) such as acid addition salts with hydrochloric acid, sulfuric acid, nitric acid, hydrobromic acid, phosphoric acid, perchloric acid, thiocyanic acid, boric acid, formic acid, acetic acid, haloacetic acid, propionic acid, glycolic acid, citric acid, tartaric acid, succinic acid, gluconic acid, lactic acid, malonic acid, fumaric acid, anthranilic acid, benzoic acid, cinnamic acid, p-toluenesulfonic acid, naphthalenesulfonic acid, sulfanilic acid, salts with alkali metal such as sodium and potasium, salts with alkaline-earth metal such as calcium, magnesium and barium, or salts with other metals such as aluminum and with bases such as ammonia and organic amines. Those salts may be manufactured by known methods from the novel benzothiazole derivatives of the present invention in a free state or may be mutually converted among the salts. When there are steric isomers such as cis-trans isomer, optical isomer and conformational isomer for the substances of the present invention, the present invention includes any and all of them. The substance of the present invention can be made into pharmaceutical preparations by a combination with a suitable pharmaceutical carriers or diluents. They can be made into various types of preparations by common methods and are able to be made into solid, semisolid, liquid or aerosol formulations for administrations by oral or parenteral means. In preparing the preparations, the substance of the present invention may be used in the form of their pharmaceutically acceptable salts, and also can be used either solely or jointly together with other pharmaceutically-active components. In the case of injections, it is possible to prepare the solutions or the suspensions in an aqueous and nonaqueous solvents such as distilled water for injection, physiological saline solution, Ringer's solution, plant oil, synthetic fatty acid glycerides, higher fatty acid esters, propylene glycol, etc., and to adjust the pH and isonicity of the solution or suspension. In the case of the preparations for oral administration, the substance of the present invention as it is or together with commonly-used excipients such as a suitable additive (e.g. lactose, mannitol, corn starch, potato starch, crystalline cellulose, etc.) is mixed with binders such as crystalline cellulose, cellulose derivatives, gum arabicum, corn starch, gelatin, etc., disintegrating agents such as corn starch, potato starch, carboxymethylcellulose, potassium carboxymethylcellulose, etc., lubricating agents such as talc, magnesium stearate, etc. and others including bulking agents, moisturizing agents, buffers, preservatives, perfumes and the like to give tablets, diluted powders, granules or capsules. Alternatively, suppositories may be prepared by mixing with fatty/oily bases (e.g. cacao butter), emulsified bases, water-soluble bases (e.g. Macrogol), hydrophilic bases, etc. In case of inhalations or aerosol preparations, the compound of the present invention in the form of a liquid or minute powder can be filled up in an aerosol container with gas or liquid spraying agent, and if desired, with conventional adjuvants such as humidifying agents or dispersing agent. They can also be used as pharmaceuticals for a non-pressurized preparation such as in a nebulizer or an atomizer. In order to make the compounds of the present invention into collyriums, they can be prepared as a solution or suspension together with an aqueous solvent such as sterile, purified water and physiologically saline solution, or a non-aqueous solvent for injection, if desired, with preservations, sterilizers, etc. It is also possible, depending upon the type of the disease, to prepare the pharmaceutical preparations which are other than those which were mentioned already and are suitable for the therapy such as, for example, ointments, poultices, etc. [Examples] The resulting compounds of the present invention were purified by common means such as distillation, chromatography and recrystallization and identified by means of, for example, elementary analysis, melting point measurement, IR, NMR, UV and MS. As hereunder, several examples of the methods of manufacturing the compounds of the present invention are given. Example 1 (1) A solution of 1 g of 6-hydroxybenzothiazole in dimethylformamide was dropped into a solution of 0.4 g of 60 % sodium hydride in 3 ml of dimethylformamide at 0 °C. After the mixture was stirred at room temperature for 1 hour, 0.75 ml of (2-methoxyethoxy)methylchloride was added dropwise into the mixture and the mixture was stirred for another 1 hour. NaCl was added to the reaction mixture and the mixture was extracted with ether. The extracts were dried over sodium sulfate and concentrated, and then the residue was purified by column-chromatography (hexane : ethyl acetate = 5 : 1) to give 0.6 g of 6-[(2-methoxyethoxy)-methoxy]benzothiazole. 1 H-NMR(CDCl 3 ): 3.38(s,3H), 3.58(m,2H), 3.87(m,2H), 7.22(dd,J=8.8,2.4Hz,1H), 7.66(d,J=2.4Hz,1H), 8.82(d,J=8.8Hz,1H), 8.86(s,1H) IR(neat) cm -1 : 2927, 1674, 1475, 1230, 1103, 999 MS(EI) m/z: 239(M + ), 89, 59 (2) The same operations as above were carried out using 4-hydroxybenzoic ethyl ester. 1.4 g of 60 % sodium hidride was washed with hexane and dissolved in 50 ml of dimethylformamide. A solution of 5 g of ethyl 4-hydroxybenzoate in dimethylformamide (50 ml) was added dropwise into this solution at 0 °C. After the mixture was stirred at room temperature for 1 hour, 4.1 ml of (2-methoxyethoxy)methylchloride was added dropwise into the mixture and the mixture was stirred for another 1 hour. NaCl was added to the reaction mixture and the mixture was extracted with ether. The extracts were dried over sodium sulfate and concentrated, and then the residue was purified by distillation (135 °C, 1 mmHg) to afford 7.0 g of ethyl 4-[(2-methoxyethoxy)methoxy]-benzoate. bp: 135 °C (1 mmHg) 1 H-NMR(CDCl 3 ): 1.38(t,J=7.1Hz,3H), 3.37(s,3H), 3.55(m,2H), 3.82(m,2H), 4.35(q,J=7.1Hz,2H), 5.32(s,2H), 7.07(d,J=8.8Hz,2H), 7.99(d,J=8.8Hz,2H) IR(neat) cm -1 : 2981, 1713, 1606, 1276, 1104, 988 MS(EI) m/z: 254(M + ), 209, 179, 121, 89, 59 (3) A solution of 1.3 N of n-butyllithium in hexane (0.7 ml) was added to a solution of 220 mg of 6-[(2-methoxyethoxy)methoxy]benzothiazole in 30 ml of tetrahydrofuran at -78 °C cooled by dry ice - acetone. The mixture was added dropwise into a solution of 234 mg of ethyl 4-[(2-methoxyethoxy)methoxy]benzoate in tetrahydrofuran (3 ml) cooled by using same way. NH 4 Cl was added to the reaction mixture and the mixture was extracted with ether. The extracts were washed with water and dried over sodium sulfate. After being concentrated, the residue was recrystallized from ethyl acetate to yield 320 mg of 6-(2-methoxyethoxy)methoxy-2-{4-[(2-methoxyethoxy)methoxy]benzoyl}benzothiazole (Compound 1). mp: 46 °C 1 H-NMR(CDCl 3 ): 3.38(s,3H), 3.38(s,3H), 3.58(m,4H), 3.86(m,4H), 5.38(s,4H), 7.18(d,J=8.8Hz,2H), 7.28(dd,J=9.1,2.2Hz,1H), 7.67(d,J=2.2Hz,1H), 8.10(d,J=9.1Hz,1H), 8.59(d,J=8.8Hz,2H) IR(KBr) cm -1 : 2877, 1598, 1488, 1214, 1117, 987 MS m/z: 447(M + ), 89, 59 Elementary analysis (C 22 H 25 NO 7 S): Calculated (C=59.05,H=5.63,N=3.13); Found (C=59.15,H=5.58,N=2.93) The same reaction as in Example 1 (1) - (3) was carried out to give the following compounds. 6-Methoxy-2-(4-methoxybenzoyl)benzothiazole (Compound 2) mp: 142 °C 1 H-NMR(DMSO-d 6 ): 3.91(s,6H), 7.17(d,J=8.9Hz,2H), 7.26(dd,J=8.9,2.4Hz,1H), 7.81(d,J=2.4Hz,1H), 8.16(d,J=8.9Hz,1H), 8.54(d,J=8.9Hz,2H) Elementary analysis (C 16 H 13 NO 3 S): Calculated (C=64.20,H=4.38,N=4.68); Found (C=64.31,H=4.52,N=4.40) 6-[(2-Methoxyethoxy)methoxy]-2-(4-nitrobenzoyl)benzothiazole (Compound 3) mp: 143-144 °C 1 H-NMR(DMSO-d 6 ): 3.22(s,3H,CH 3 ), 3.46-3.50(m,2H,CH 2 ), 3.76-3.80(m,2H,CH 2 ), 5.42(s,2H,CH 2 ), 7.37(dd,J=9.2,2.6Hz,1H,Ar-H), 7.93(d,J=2.6Hz,1H,Ar-H), 8.21(d,J=9.2Hz,1H,Ar-H), 8.43(d,J=8.8Hz,2H,Ar-H), 8.56(d,J=8.8Hz,2H,Ar-H) IR(KBr) cm -1 : 1645(C=O), 1597, 1525(NO 2 ), 1351(NO 2 ) MS m/z: 388(M + ) Elementary analysis (C 18 H 16 N 2 O 6 S): Calculated (C=55.66,H=4.15,N=7.21); Found (C=55.69,H=4.08,N=7.61) 6-[(2-Methoxyethoxy)methoxy]-2-(3-nitrobenzoyl)benzothiazole (Compound 4) mp: 85-86 °C 1 H-NMR(DMSO-d 6 ): 3.22(s,3H,CH 3 ), 3.46-3.50(m,2H,CH 2 ), 3.76-3.80(m,2H,CH 2 ), 5.42(s,2H,CH 2 ), 7.37(d,J=9.0Hz,1H,Ar-H), 7.90-7.96(m,2H,Ar-H), 8.22(d,J=9.0Hz,1H,Ar-H), 8.58(d,J=7.6Hz,1H,Ar-H), 8.81(d,J=7.6Hz,1H,Ar-H), 9.21(s,1H,OH) IR(KBr) cm -1 : 1643(C=O), 1527(NO 2 ), 1491, 1350(NO 2 ) MS m/z: 388(M + ) Elementary analysis (C 18 H 16 N 2 O 6 S): Calculated (C=55.66,H=4.15,N=7.21); Found (C=55.60,H=4.06,N=7.52) 6-[(2-Methoxyethoxy)methoxy]-2-(2-nitrobenzoyl)benzothiazole (Compound 5) mp: 89-90 °C 1 H-NMR(DMSO-d 6 ): 3.21(s,3H,CH 3 ), 3.46-3.50(m,2H,CH 2 ), 3.76-3.80(m,2H,CH 2 ), 5.39(s,2H,CH 2 ), 7.29(dd,J=9.0,2.4Hz,1H,Ar-H), 7.88-7.94(m,3H,Ar-H), 7.99-8.04(m,2H,Ar-H), 8.31(d,J=8.8Hz,1H,Ar-H) IR(KBr) cm -1 : 1670(C=O), 1603, 1525(NO 2 ), 1354(NO 2 ) MS m/z: 388(M + ) Elementary analysis (C 18 H 16 N 2 O 6 S): Calculated (C=55.66,H=4.15,N=7.21); Found (C=55.84,H=4.14,N=7.09) 2-(3-Fluorobenzoyl)-6-[(2-methoxyethoxy)methoxy] benzothiazole (Compound 6) mp: 60-61 °C 1 H-NMR(CDCl 3 ): 3.38(s,3H,CH 3 ), 3.56-3.64(m,2H,CH 2 ), 3.87-3.90(m,2H,CH 2 ), 5.38(s,2H,CH 2 ), 7.29(dd,J=9.2,2.6Hz,1H,Ar-H), 7.36(ddd,J=8.4,8.4,2.4Hz,1H,Ar-H), 7.53(ddd,J=8.4,8.4,5.6Hz,1H,Ar-H), 7.68(d,J=2.4Hz,1H,Ar-H), 8.13(d,J=9.2Hz,1H,Ar-H), 8.31(ddd,J=7.6,2.4,2.4Hz,1H,Ar-H), 8.36(d,J=7.6Hz,1H,Ar-H) IR(KBr) cm -1 : 1637(C=O), 1605, 1583, 1497 MS m/z: 361(M + ) Elementary analysis (C 18 H 16 FN 2 O 6 S 0.6EtOAc): Calculated (C=59.16,H=5.06,N=3.38); Found (C=59.32,H=5.45,N=3.78) (4) 0.2 ml of trifluoroacetic acid was added to a solution of 4 g of the compound 1 in water - methanol and the mixture was stirred for 48 hours at 70 °C. After the reaction was completed, methanol was evaporated and the crystals were collected by filtration and dried to give 2.3 g of 6-hydroxy-2-(4-hydroxybenzoyl)benzothiazole (Compound 7). mp: 46 °C 1 H-NMR(aceton-d 6 ): 7.01(d,J=8.9Hz,2H), 7.18(dd,J=8.9,2.4Hz,1H), 7.52(d,J=2.4Hz,1H), 8.05(d,J=8.9Hz,1H), 8.58(d,J=8.9Hz,2H), 9.15(br,1H), 9.40(br,1H) IR(KBr) cm -1 : 3463, 1602, 1589, 1491, 1249, 1176, 1119, 875 MS m/z: 271(M + ), 243, 121 Elementary analysis (C 14 H 9 NO 3 S 0.8H 2 O): Calculated (C=58.84,H=3.74,N=4.90); Found (C=58.78,H=3.55,N=4.54) The same reaction as in Example 1 (4) was carried out to give the following compounds. 6-Hydroxy-2-(4-nitrobenzoyl)benzothiazole (Compound 8) mp: 238-239 °C 1 H-NMR(DMSO-d 6 ): 7.16(dd,J=9.0,2.2Hz,1H,Ar-H), 7.54(d,J=2.2 Hz,2H,Ar-H), 8.10(d,J=9.0Hz,1H,Ar-H), 8.43(d,J=8.8Hz,2H,Ar-H), 8.57(d,J=8.8Hz,2H,Ar-H), 10.47(brs,1H,OH) IR(KBr) cm -1 : 3464(OH), 1641(C=O), 1603, 1518(NO 2 ), 1356(NO 2 ) MS m/z: 300(M + ) Elementary analysis (C 14 H 8 N 2 O 4 S 0.1H 2 O): Calculated (C=55.66,H=2.74,N=9.27); Found (C=55.45,H=2.73,N=9.07) 6-Hydroxy-2-(3-nitrobenzoyl)benzothiazole (Compound 9) mp: >300 °C 1 H-NMR(DMSO-d 6 ): 7.37(d,J=8.0Hz,1H,Ar-H), 7.87(dd,J=8.6,8.0Hz,1H,Ar-H), 8.07(d,J=8.6Hz,1H,Ar-H), 8.52(d,J=8.0Hz,1H,Ar-H), 8.70(d,J=8.0Hz,1H,Ar-H), 9.10(s,1H,Ar-H), 10.92(brs,1H,OH) IR(KBr) cm -1 : 3422(OH), 1650(C=O), 1608, 1524(NO 2 ), 1498, 1355(NO 2 ), 1259 Elementary analysis (C 14 H 8 N 2 O 4 S 0.15H 2 O): Calculated (C=55.50,H=2.76,N=9.25); Found (C=55.74,H=2.65,N=9.00) 6-Hydroxy-2-(2-nitrobenzoyl)benzothiazole (Compound 10) mp: 265-266 °C (decomp.) 1 H-NMR(DMSO-d 6 ): 7.37(d,J=8.0Hz,1H,Ar-H), 7.87(dd,J=8.6,8.0Hz,1H,Ar-H), 8.07(d,J=8.6Hz,1H,Ar-H), 8.52(d,J=8.0Hz,1H,Ar-H), 8.70(d,J=8.0Hz,1H,Ar-H), 9.10(s,1H,Ar-H), 10.92(brs,1H,OH) IR(KBr) cm -1 : 3449(OH), 1663(C=O), 1613, 1557, 1524(NO 2 ), 1497, 1462, 1349(NO 2 ), 1271, 1250, 1205 MS m/z: 300(M + ) Elementary analysis (C 14 H 8 N 2 O 4 S 0.55H 2 O): Calculated (C=59.38,H=3.24,N=4.95); Found (C=59.70,H=3.42,N=4.61) Example 2 4 ml of acetic anhydride was added to a solution of 2.3 g of the compound 3 hydrochloride in 40 ml of pyridine and the mixture was stirred overnight. The reaction mixture was poured into 50 ml of ice water and the resulting precipitate was separated. The solid was recrystallized from benzene to afford 1.8 g of 6-acetoxy-2- (4-acetoxybenzoyl)benzothiazole (Compound 11). mp: 183 °C 1 H-NMR(DMSO-d 6 ): 8.52(d,J=8.7Hz,2H), 8.33(d,J=8.9Hz,1H), 8.12(d,J=2.2Hz,1H), 7.47(dd,J=8.9,2.2Hz,1H), 7.42(d,J=8.7Hz,2H), 2.35(s,3H), 2.34(s,3H) IR(KBr) cm -1 : 1763, 1493, 1186, 1161, 872 MS m/z: 355(M + ), 313, 271, 243, 121, 43 Elementary analysis (C 22 H 25 NO 7 S): Calculated (C=60.84,H=3.69,N=3.94); Found (C=60.98,H=3.63,N=3.55) Example 3 4.37 g of 6-hydroxybenzothiazole and 11.0 g of 4-hydroxybenzaldehyde were dissolved in a mixed solvent of 22 ml of water and 66 ml of acetic acid containing 1.3 ml of conc. sulfuric acid and the mixture was cooled at 0 °C. 65 ml of an aqueous solution containing 25.7 g of FeSO 4 7H 2 O and 3 equivalent of t-butylhydroperoxide were separatelly added dropwise into the mixture with stirring. After the mixture was stirred for 1 hour, the crystals were collected by filtration, dissolved in ethyl acetate and washed with water. The organic layer was dried over mirabilite and concentrated and then the residue was recrystallized from ethanol - water (1 : 1) to yield 5.50 g of the compound 7. The same reaction as in Example 3 was carried out to give the following compounds. 2-(4-Hydroxybenzoyl)-6-methoxybenzothiazole (Compound 12) mp: 193-194 °C 1 H-NMR(DMSO-d 6 ): 3.90(s,1H,CH 3 ), 6.97(d,J=8.6Hz,2H,Ar-H), 7.26(dd,J=9.0,2.0Hz,1H,Ar-H), 7.81(d,J=2.0Hz,1H,Ar-H), 8.16(d,J=9.0Hz,1H,Ar-H), 8.16(d,J=8.6Hz,2H,Ar-H), 10.68(brs,1H,OH) IR(KBr) cm -1 : 3386(OH), 1603(C=O), 1578, 1491, 1254 MS m/z: 285(M + ) Elementary analysis (C 15 H 11 NO 3 S): Calculated (C=63.14,H=3.89,N=4.91); Found (C=63.22,H=3.88,N=4.92) 6-Hydroxy-2-(4-methoxybenzoyl)benzothiazole (Compound 13) mp: 190-191 °C (decomp.) 1 H-NMR(DMSO-d 6 ): 3.90(s,3H,CH 3 ), 7.10-7.20(m,3H,Ar-H), 7.51(s,1H,Ar-H), 8.09(d,J=9.0Hz,1H,Ar-H), 8.53(d,J=8.6Hz,1H,Ar-H), 10.34(brs,1H,OH) IR(KBr) cm -1 : 3340(OH), 1601(C=O), 1489, 1257 MS m/z: 285(M + ) Elementary analysis (C 15 H 11 NO 3 S): Calculated (C=63.14,H=3.89,N=4.91); Found (C=63.23,H=3.98,N=4.51) 2-(4-Hydroxybenzoyl)benzothiazole (Compound 14) mp: 173-174 °C 1 H-NMR(DMSO-d 6 ): 6.99(d,J=8.6Hz,2H,Ar-H), 7.60-7.72(m,2H,Ar-H), 8.28(dd,J=7.0,7.0Hz,2H,Ar-H), 8.28(dd,J=7.0,7.0Hz,2H,Ar-H), 8.49(d,J=8.6Hz,1H,Ar-H), 10.73(brs,1H,OH) IR(KBr) cm -1 : 3304(OH), 1572(C=O), 1485, 1288 MS m/z: 255(M + ) Elementary analysis (C 14 H 9 NO 2 S): Calculated (C=65.87,H=3.55,N=5.49); Found (C=65.94,H=3.53,N=5.15) 2-Benzoyl-6-hydroxybenzothiazole (Compound 15) mp: 146-147 °C 1 H-NMR(DMSO-d 6 ): 7.14(dd,J=11.4,1.8Hz,1H,Ar-H), 7.52(d,J=1.8Hz,1H,Ar-H), 7.63(dd,J=8.0,7.2Hz,2H,Ar-H), 8.10(tt,J=7.2,1.0Hz,1H,Ar-H), 8.42(dd,J=8.0,1.0Hz,2H,Ar-H), 10.39(brs,1H,OH) IR(KBr) cm -1 : 3327(OH), 1610(C=O), 1468, 1255 MS m/z: 255(M + ) Elementary analysis (C 14 H 9 NO 2 S 0.1H 2 O): Calculated (C=65.40,H=3.60,N=5.45); Found (C=65.13,H=3.58,N 5.32) 2-(2,4-Dihidroxybenzoyl)-6-methoxybenzothiazole (Compound 16) mp: 220-221 °C (decomp.) 1 H-NMR(DMSO-d 6 ): 3.90(s,3H,CH 3 ), 6.36(s,1H,Ar-H), 6.53(d,J=7.8Hz,1H,Ar-H), 7.27(d,J=8.6Hz,1H,Ar-H), 7.83(s,1H,Ar-H), 8.17(d,J=8.6Hz,1H,Ar-H), 9.06(d,J=7.8Hz,1H,Ar-H), 11.15(brs,1H,OH), 12.36(brs,1H,OH) IR(KBr) cm -1 : 3427(OH), 1633(C=O), 1485, 1230 MS m/z: 301(M + ) Elementary analysis (C 15 H 11 NO 4 S 0.1H 2 O): Calculated (C=59.44,H=3.72,N=4.62); Found (C=59.39,H=3.61,N=4.37) 2-(2,4-Dihidroxybenzoyl)-6-hydroxybenzothiazole (Compound 17) mp: 239-240 °C (decomp.) 1 H-NMR(DMSO-d 6 ): 6.34(s,1H,Ar-H), 6.51(d,J=9.0Hz,1H,Ar-H), 7.13(dd,J=9.0,2.4Hz,1H,Ar-H), 7.51(d,J=2.2Hz,1H,Ar-H), 8.09(d,J=9.0Hz,1H,Ar-H), 9.05(d,J=9.0Hz,1H,Ar-H), 10.40(brs,1H,OH), 12.42(brs,1H,OH) IR(KBr) cm -1 : 3388(C=O), 3302(C=O), 1633(C=O), 1606, 1491, 1254 MS m/z: 287(M + ) Elementary analysis (C 14 H 9 NO 4 S 1/3H 2 O): Calculated (C=57.33,H=3.32,N=4.78); Found (C=57.14,H=3.25,N=4.54) 2-(3-Hydroxybenzoyl)-6-methoxybenzothiazole (Compound 18) mp: 174-175 °C 1 H-NMR(DMSO-d 6 ): 3.90(s,3H,CH 3 ), 7.14(d,J=7.8Hz,1H,Ar-H), 7.28(d,J=8.8Hz,1H,Ar-H), 7.43(dd,J=7.8,7.8Hz,1H,Ar-H), 7.80-7.90(m,2H,Ar-H), 7.93(d,J=7.8Hz,1H,Ar-H), 8.18(d,J=8.8Hz,1H,Ar-H), 9.92(brs,1H,OH) IR(KBr) cm -1 : 3423(OH), 1585(C=O), 1489, 1454, 1263, 1223 MS m/z: 285(M + ) Elementary analysis (C 15 H 11 NO 3 S): Calculated (C=63.14,H=3.89,N=4.91); Found (C=62.94,H=3.80,N=4.59) 6-Hydroxy-2-(3-hydroxybenzoyl)benzothiazole (Compound 19) mp: 249-250 °C (decomp.) 1 H-NMR(DMSO-d 6 ): 7.13(s,2H,Ar-H), 7.42(dd,J=8.8Hz,1H,Ar-H), 7.43(dd,J=8.8,6.8Hz,1H,Ar-H), 7.52(s,1H,Ar-H), 7.80(s,1H,Ar-H), 7.91(d,J=6.8Hz,1H,Ar-H), 8.09(d,J=8.8Hz,1H,Ar-H), 9.91(brs,1H,OH), 10.39(brs,1H,OH) IR(KBr) cm -1 : 3388(OH), 3286(OH), 1585(C=O), 1489, 1456, 1238 MS m/z: 271(M + ) Elementary analysis (C 14 H 9 NO 3 S 0.1H 2 O): Calculated (C=61.57,H=3.40,N=5.13); Found (C=61.58,H=3.45,N=5.10) 2-(4-Bromobenzoyl)-6-methoxybenzothiazole (Compound 20) mp: 190-190.5 °C 1 H-NMR(DMSO-d 6 ): 3.90(s,3H,CH 3 ), 7.28(d,J=9.0Hz,1H,Ar-H), 7.82-7.89(m,3H,Ar-H), 8.17(d,J=9.0Hz,1H,Ar-H), 8.38(d,J=8.2Hz,2H,Ar-H) IR(KBr) cm -1 : 1637(C=O), 1605, 1585, 1497, 1481, 1257, 1230 MS m/z: 349(M + , 81 Br), 347(M + , 79 Br) Elementary analysis (C 15 H 10 BrNO 2 S): Calculated (C=51.74,H=2.89,N=4.02); Found (C=51.46,H=2.80,N=3.82) 2-(4-Bromobenzoyl)-6-hydroxybenzothiazole (Compound 21) mp: 178-179 °C 1 H-NMR(DMSO-d 6 ): 7.15(dd,J=8.8,2.0Hz,1H,Ar-H), 7.53(d,J=2.0Hz,1H,Ar-H), 7.86(d,J=8.6Hz,2H,Ar-H), 8.09(d,J=8.8Hz,1H,Ar-H), 8.37(d,J=8.6Hz,2H,Ar-H), 10.43(brs,1H,OH) IR(KBr) cm -1 : 3340(OH), 1620, 1603(C=O), 1479, 1236 MS m/z: 335(M + , 81 Br), 333(M + , 79 Br) Elementary analysis (C 14 H 8 BrNO 2 S): Calculated (C=50.32,H=2.41,N=4.20); Found (C=50.08,H=2.45,N=4.13) 6-Hydroxy-2-(2-hydroxybenzoyl)benzothiazole (Compound 22) mp: 173-175 °C 1 H-NMR(DMSO-d 6 ): 7.02(d,J=6.4Hz,2H,Ar-H), 7.12(d,J=8.8Hz,1H,Ar-H), 7.49-7.59(m,2H,Ar-H), 8.06(d,J=8.8Hz,1H,Ar-H), 8.36(d,J=7.8Hz,1H,Ar-H), 10.43(brs,1H,OH), 10.99(brs,1H,OH) IR(KBr) cm -1 : 3417(OH), 3385(OH), 1622(C=O), 1589, 1487, 1468, 1240 MS m/z: 271(M + ) Elementary analysis (C 14 H 9 NO 3 S): Calculated (C=61.98,H=3.34,N=5.16); Found (C=61.75,H=3.28,N=5.04) 2-(2-Chlorobenzoyl)-6-hydroxybenzothiazole (Compound 23) mp: 172-173 °C 1 H-NMR(DMSO-d 6 ); 7.12(d,J=8.0Hz,1H,Ar-H), 7.54(brs,2H,Ar-H), 7.63(s,2H,Ar-H), 7.77(d,J=6.4Hz,1H,Ar-H), 8.01(d,J=8.0Hz,1H,Ar-H), 10.43(brs,1H,OH), 10.99(brs,1H,OH) IR(KBr) cm -1 : 3459(OH), 1648(C=O), 1601, 1485, 1255 MS m/z: 291(M + , 37 Cl), 289(M + , 35 Cl) Elementary analysis (C 14 H 8 ClNO 2 S 0.1H 2 O): Calculated (C=57.68,H=2.83,N=4.80); Found (C=57.66,H=2.78,N=4.58) 2-(3-Chlorobenzoyl)-6-hydroxybenzothiazole (Compound 24) mp 156-157 °C 1 H-NMR(DMSO-d 6 ): 7.15(d,J=8.6Hz,1H,Ar-H), 7.53(s,1H,Ar-H), 7.67(dd,J=8.0,7.6Hz,1H,Ar-H), 7.82(d,J=8.0Hz,1H,Ar-H), 8.12(d,J=8.6Hz,1H,Ar-H) 8.36(d,J=7.6Hz,1H,Ar-H), 8.41(s,1H,Ar-H), 10.45(brs,1H,OH) IR(KBr) cm -1 : 3456(OH), 1649(C=O), 1601, 1483, 1255 MS m/z: 291(M + , 37 Cl), 289(M + , 35 Cl) Elementary analysis (C 14 H 8 ClNO 2 S): Calculated (C=58.04,H=2.78,N=4.83); Found (C=58.34,H=2.78,N=4.43) 2-(4-Chlorobenzoyl)-6-hydroxybenzothiazole (Compound 25) mp: 177-177.5 °C 1 H-NMR(DMSO-d 6 ): 6.64(dd,J=9.0,2.2Hz,1H,Ar-H), 7.54(d,J=2.2Hz,1H,Ar-H), 7.71(d,J=8.8Hz,2H,Ar-H), 8.10(d,J=9.0Hz,1H,Ar-H), 8.46(d,J=8.8Hz,2H,Ar-H), 10.43(brs,1H,OH) IR(KBr) cm -1 : 3396(OH), 1622, 1603(C=O), 1483, 1259, 1234 MS m/z: 291(M + , 37 Cl), 289(M + , 35 Cl) Elementary analysis (C 14 H 8 ClNO 2 S): Calculated (C=58.04,H=2.78,N=4.83); Found (C=58.34,H=2.90,N=4.55) 6-Hydroxy-2-(2-methylbenzoyl)benzothiazole (Compound 26) mp: 200-202 °C 1 H-NMR(DMSO-d 6 ): 2.37(s,3H,CH 3 ), 7.11(d,J=9.2Hz,1H,Ar-H), 7.34-7.41(m,2H,Ar-H), 7.49-7.57(m,2H,Ar-H), 7.83(d,J=7.6Hz,1H,Ar-H), 8.01(d,J=9.0Hz,1H,Ar-H), 10.41(brs,1H,OH) IR(KBr) cm -1 : 3410(OH), 1639, 1610(C=O), 1552, 1498, 1468, 1257 MS m/z: 269(M + ) Elementary analysis (C 15 H 11 NO 2 S 0.1EtOH): Calculated (C=66.65,H=4.27,N=5.11); Found (C=67.07,H=4.21,N=4.68) 6-Hydroxy-2-(3-methylbenzoyl)benzothiazole (Compound 27) mp: 170-171 °C 1 H-NMR(DMSO-d 6 ): 2.44(s,3H,CH 3 ), 7.14(d,J=8.6Hz,1H,Ar-H), 7.46-7.60(m,3H,Ar-H), 8.10(d,J=8.6Hz,1H,Ar-H), 8.15(s,1H,Ar-H), 8.25(d,J=7.0Hz,1H,Ar-H), 10.43(brs,1H,OH) IR(KBr) cm -1 : 3407(OH), 1603(C=O), 1595, 1487, 1233, 1198 MS m/z: 269(M + ) 6-Hydroxy-2-(4-methylbenzoyl)benzothiazole (Compound 28) mp: 186-187 °C 1 H-NMR(DMSO-d 6 ): 2.44(s,3H,CH 3 ), 7.14(dd,J=9.0,2.4Hz,1H,Ar-H), 7.44(d,J=8.2Hz,2H,Ar-H), 7.52(d,J=2.4Hz,1H,Ar-H), 8.09(d,J=9.0Hz,1H,Ar-H), 8.37(d,J=8.2Hz,2H,Ar-H), 10.38(brs,1H,OH) IR(KBr) cm -1 : 3398(OH), 1635, 1605, 1558, 1492, 1259 MS m/z: 269(M + ) Elementary analysis (C 15 H 11 NO 2 S): Calculated (C=66.90,H=4.12,N=5.20); Found (C=67.31,H=4.07,N=4.77) 2-(3-Chloro-4-hydroxybenzoyl)-6-hydroxybenzothiazole (Compound 29) mp: 225-226 °C 1 H-NMR(DMSO-d 6 ): 7.13(dd,J=9.0,2.2Hz,1H,Ar-H), 7.18(d,J=8.6Hz,1H,Ar-H), 7.51(d,J=2.2Hz,1H,Ar-H), 8.10(d,J=9.0Hz,1H,Ar-H), 8.38(dd,J=8.6,2.2Hz,1H,Ar-H), 8.59(d,J=2.0Hz,1H,Ar-H), 10.36(brs,1H,OH), 11.50(brs,1H,OH) IR(KBr) cm -1 ; 3408(OH), 1593(C=O), 1487, 1252 MS m/z: 307(M + , 37 Cl), 305(M + , 35 Cl) Elementary analysis (C 14 H 8 ClNO 3 S 0.1H 2 O): Calculated (C=54.68,H=2.69,N=4.55); Found (C=54.51,H=2.70,N=4.55) 6-Hydroxy-2-(4-methoxycarbonylbenzoyl)benzothiazole (Compound 30) mp: 205-206 °C 1 H-NMR(DMSO-d 6 ) 3.92(s,3H,CH 3 ), 7.15(dd,J=9.0,2.4Hz,1H,Ar-H), 7.54(d,J=2.4Hz,1H,Ar-H), 8.10(d,J=9.0Hz,1H,Ar-H), 8.17(d,J=8.4Hz,2H,Ar-H), 8.49(d,J=8.4Hz,2H,Ar-H), 10.50(brs,1H,OH) IR(KBr) cm -1 : 3394(OH), 1705(C=O), 1645(C=O), 1601, 1485, 1230 MS m/z: 313(M + ) Elementary analysis (C 16 H 11 NO 4 S): Calculated (C=61.33,H=3.54,N=4.47); Found (C=61.46,H=3.53,N=4.22) 2-[4-(N,N-Dimethylamino)benzoyl]-6-hydroxybenzothiazole (Compound 31) mp: 213-214 °C 1 H-NMR(DMSO-d 6 ): 3.09(s,6H,CH 3 ), 6.84(d,J=8.6Hz,2H,Ar-H), 7.11(d,J=8.6Hz,1H,Ar-H), 7.48(s,1H,Ar-H), 8.05(d,J=8.6Hz,1H,Ar-H), 8.48(d,J=8.6Hz,2H,Ar-H), 10.28(brs,1H,OH) IR(KBr) cm -1 : 3423(OH), 1603(C=O), 1576, 1489, 1196 MS m/z: 298(M + ) Elementary analysis (C 16 H 14 N 2 O 2 S 1/3H 2 O): Calculated (C=63.14,H=4.86,N=9.20); Found (C=62.96,H=4.87,N=8.97) 6-Hydroxy-2-(2-hydroxy-3-methoxybenzoyl)benzothiazole (Compound 32) mp: 227-228 °C 1 H-NMR(DMSO-d 6 ): 3.85(s,3H,CH 3 ), 6.96(dd,J=9.0,8.0Hz,1H,Ar-H), 7.12(d,J=8.0Hz,1H,Ar-H), 7.26(d,J=8.0Hz,1H,Ar-H), 7.51(s,1H,Ar-H), 7.87(d,J=7.8Hz,1H,Ar-H), 8.05(d,J=9.0Hz,1H,Ar-H), 10.63(brs,1H,OH) IR(KBr) cm -1 : 3439(OH), 1618(C=O), 1454, 1254, 1249 MS m/z: 301(M + ) Elementary analysis (C 15 H 11 NO 4 S 0.2H 2 O): Calculated (C=59.09,H=3.77,N=4.59); Found (C=59.26,H=3.73,N=4.27) 6-Hydroxy-2-(4-hydroxy-3-methoxybenzoyl)benzothiazole (Compound 33) mp: 212-213 °C 1 H-NMR(DMSO-d 6 ): 3.88(s,3H,CH 3 ), 6.99(d,J=8.4Hz,1H,Ar-H), 7.13(d,J=8.0Hz,1H,Ar-H), 7.50(s,1H,Ar-H), 8.00(s,1H,Ar-H), 8.08(d,J=8.0Hz,1H,Ar-H), 8.29(d,J=8.4Hz,1H,Ar-H), 10.33(brs,1H,OH) IR(KBr) cm -1 : 3386(OH), 3251(OH), 1605(C=O), 1489, 1281, 1234 MS m/z: 300(M + -H) Elementary analysis (C 15 H 9 NO 4 S 0.9H 2 O): Calculated (C=56.74,H=4.06,N=4.41); Found (C=56.93,H=3.96,N=4.40) 6-Hydroxy-2-(3-hydroxy-4-methoxybenzoyl)benzothiazole (Compound 34) mp: 219-220.5 °C 1 H-NMR(DMSO-d 6 ): 3.90(s,3H,CH 3 ), 7.13(d,J=8.6Hz,1H,Ar-H), 7.15(d,J=8.8Hz,1H,Ar-H), 7.49(s,1H,Ar-H), 7.89(s,1H,Ar-H), 8.08(d,J=8.8Hz,1H,Ar-H), 8.19(d,J=8.6Hz,1H,Ar-H), 9.57(brs,1H,OH), 10.33(brs,1H,OH) IR(KBr) cm -1 : 3386(OH), 1605(C=O), 1489, 1273, 1225 MS m/z: 301(M + ) Elementary analysis (C 15 H 9 NO 4 S 0.5H 2 O): Calculated (C=58.06,H=3.89,N=4.51); Found (C=57.86,H=3.81,N=4.37) 6-Hydroxy-2-(3-Chloro-4-methoxybenzoyl)benzothiazole (Compound 35) mp: 232-234 °C 1 H-NMR(DMSO-d 6 ): 4.01(s,3H,CH 3 ), 7.14(d,J=8.4Hz,1H,Ar-H), 7.39(d,J=8.8Hz,1H,Ar-H), 7.51(s,1H,Ar-H), 8.11(d,J=8.8Hz,1H,Ar-H), 8.54(d,J=8.4Hz,1H,Ar-H), 8.56(s,1H,Ar-H), 10.40(brs,1H,OH) IR(KBr) cm -1 : 3363(OH), 1599(C=O), 1578, 1483, 1282, 1228 MS m/z: 321(M + , 37 Cl), 319(M + , 35 Cl) Elementary analysis (C 15 H 10 ClNO 3 S): Calculated (C=56.34,H=3.15,N=4.38); Found (C=56.49,H=3.18,N=4.12) 6-Hydroxy-2-(4-hydroxymethylbenzoyl)benzothiazole (Compound 36) mp: 209-210 °C 1 H-NMR(DMSO-d 6 ): 4.64(s,2H,CH 2 ), 5.43(s,1H,OH), 7.14(d,J=7.4Hz,1H,Ar-H), 7.50-7.58(m,3H,Ar-H), 8.10(d,J=7.4Hz,1H,Ar-H), 8.41(d,J=6.8Hz,1H,Ar-H), 10.39(brs,1H,OH) IR(KBr) cm -1 : 3423(OH), 3265(OH), 1603(C=O), 1483, 1221 MS m/z: 285(M + ) Elementary analysis (C 15 H 11 NO 3 S): Calculated (C=63.14,H=3.89,N=4.91); Found (C=63.27,H=3.86,N=4.65) 2-(4-Fluorobenzoyl)-6-hydroxybenzothiazole (Compound 37) mp: 179-180 °C 1 H-NMR(DMSO-d 6 ): 7.15(d,J=8.6Hz,1H,Ar-H), 7.47(t,J=8.2Hz,2H,Ar-H), 7.53(s,1H,Ar-H), 8.10(d,J=8.6Hz,1H,Ar-H), 8.55(s,2H,Ar-H), 10.42(brs,1H,OH) IR(KBr) cm -1 : 3348(OH), 1626(C=O), 1599, 1489, 1258, 1161 MS m/z: 273(M + ) Elementary analysis (C 14 H 8 FNO 2 S): Calculated (C=61.53,H=2.95,N=5.13); Found (C=61.39,H=3.23,N=4.90) 6-Hydroxy-2-(3-methoxybenzoyl)benzothiazole (Compound 38) mp: 166-167 °C 1 H-NMR(DMSO-d 6 ): 3.87(s,3H,CH 3 ), 7.15(d,J=8.8Hz,1H,Ar-H), 7.33(t,J=7.2Hz,1H,Ar-H), 7.52(s,1H,Ar-H), 7.55(dd,J=7.6,7.2Hz,1H,Ar-H), 7.94(s,1H,Ar-H), 8.06(d,J=7.6Hz,1H,Ar-H), 8.11(d,J=8.8Hz,1H,Ar-H), 10.41(brs,1H,OH) IR(KBr) cm -1 : 3383(OH), 1595(C=O), 1471, 1263 MS m/z: 285(M + ) Elementary analysis (C 15 H 11 NO 3 S 0.1H 2 O): Calculated (C=62.74,H=3.93,N=4.88); Found (C=62.55,H=3.77,N=4.57) 6-Hydroxy-2-(2-methoxybenzoyl)benzothiazole (Compound 39) mp: 184.5-185.5 °C 1 H-NMR(DMSO-d 6 ) 3.73(s,3H,CH 3 ), 7.06-7.14(m,2H,Ar-H), 7.22(d,J=7.8Hz,1H,Ar-H), 7.51(s,1H,Ar-H), 7.56-7.63(m,3H,Ar-H), 7.97(d,J=8.8Hz,1H,Ar-H), 10.36(brs,1H,OH) IR(KBr) cm -1 : 3421(OH), 1627(C=O), 1610, 1554, 874 MS m/z: 285(M + ) Elementary analysis (C 15 H 11 NO 3 S 0.1H 2 O): Calculated (C=62.74,H=3.93,N=4.88); Found (C=62.92,H=3.88,N=4.49) 2-(4-Acetoxybenzoyl)-6-hydroxybenzothiazole (Compound 40) mp: 176-177 °C 1 H-NMR(DMSO-d 6 ) 2.34(s,3H,CH 3 ), 7.12(dd,J=9.0,2.0Hz,1H,Ar-H), 7.40(d,J=8.6Hz,2H,Ar-H), 7.53(d,J=2.0Hz,1H,Ar-H), 8.11(d,J=9.0Hz,1H,Ar-H), 8.49(d,J=8.6Hz,2H,Ar-H), 10.41(brs,1H,OH) IR(KBr) cm -1 : 3379(OH), 1767(C=O), 1601(C=O), 1483, 1254, 1198 MS m/z: 313(M + ) Elementary analysis (C 16 H 11 NO 4 S 0.1H 2 O): Calculated (C=60.98,H=3.58,N=4.44); Found (C=61.11,H=3.55,N=4.09) 2-(4-Acetamidobenzoyl)-6-hydroxybenzothiazole (Compound 41) mp: 190-191 °C (decomp.) 1 H-NMR(DMSO-d 6 ): 2.12(s,3H,CH 3 ), 7.14(d,J=9.0Hz,1H,Ar-H), 7.51(s,1H,Ar-H), 7.81(d,J=8.6Hz,2H,Ar-H), 8.10(d,J=9.0Hz,1H,Ar-H), 8.48(d,J=8.6Hz,2H,Ar-H), 10.36(brs,1H,OH), 10.40(s,1H,NH) IR(KBr) cm -1 : 3400(OH), 3271(NH), 1678(C=O), 1622(C=O), 1581, 1498, 1261 MS m/z: 312(M + ) Elementary analysis (C 16 H 12 N 2 O 3 S 0.2EtOH): Calculated (C=61.26,H=3.96,N=8.38); Found (C=61.54,H=3.96,N=8.38) 2-(4-t-Butylbenzoyl)-6-hydroxybenzothiazole (Compound 42) mp: 168-169 °C 1 H-NMR(DMSO-d 6 ): 1.35(s,9H,CH 3 ), 7.14(dd,J=9.0,2.0Hz,1H,Ar-H), 7.52(d,J=2.0Hz,1H,Ar-H), 7.65(d,J=8.4Hz,2H,Ar-H), 8.08(d,J=9.0Hz,1H,Ar-H), 8.37(d,J=8.4Hz,2H,Ar-H), 10.39(brs,1H,OH) IR(KBr) cm -1 : 3219(OH), 2962, 1632(C=O), 1606, 1552, 1488, 1257 MS m/z: 311(M + ) Elementary analysis (C 18 H 17 NO 2 S): Calculated (C=69.43,H=5.50,N=4.50); Found (C=69.46,H=5.63,N=4.31) 2-(3,4-Diacetoxybenzoyl)-6-hydroxybenzothiazole (Compound 43) mp: 145-146 °C 1 H-NMR(DMSO-d 6 ): 2.35(s,3H,CH 3 ), 2.50(s,3H,CH 3 ), 7.15(dd,J=9.0,2.4Hz,1H,Ar-H), 7.53(d,J=2.4Hz,1H,Ar-H), 7.56(d,J=8.6Hz,1H,Ar-H), 8.11(d,J=9.0Hz,1H,Ar-H), 8.28(d,J=2.0Hz,1H,Ar-H), 8.44(dd,J=8.6,2.0Hz,1H,Ar-H), 10.46(brs,1H,OH) IR(KBr) cm -1 : 3356(OH), 1770(C=O), 1730(C=O), 1643(C=O), 1603, 1489, 1373, 1211 MS m/z: 371(M + ) Elementary analysis (C 18 H 13 NO 6 S): Calculated (C=58.22,H=3.53,N=3.77); Found (C=58.45,H=3.68,N=3.56) 6-Hydroxy-2-(4-iso-propylbenzoyl)benzothiazole (Compound 44) mp: 108-110 °C 1 H-NMR(DMSO-d 6 ): 1.27(d,J=6.8Hz,6H,CH 3 ), 2.97-3.07(m,1H,CH), 7.14(dd,J=9.0,2.2Hz,1H,Ar-H), 7.47-7.53(m,3H,Ar-H), 8.09(d,J=9.0Hz,1H,Ar-H), 8.37(d,J=8.2Hz,2H,Ar-H), 10.39(brs,1H,OH) IR(KBr) cm -1 : 3362(OH), 2958, 1599(C=O), 1487, 1259 MS m/z: 297(M + ) Elementary analysis (C 17 H 15 NO 2 S): Calculated (C=68.66,H=5.08,N=4.71); Found (C=68.97,H=5.21,N=4.50) 6-Hydroxy-2-(4-trifluoromethylbenzoyl)benzothiazole (Compound 45) mp: 183-184 °C (decomp.) 1 H-NMR(DMSO-d 6 ): 7.15(d,J=9.0Hz,1H,Ar-H), 7.54(s,1H,Ar-H), 8.01(d,J=8.0Hz,2H,Ar-H), 8.10(d,J=9.0Hz,1H,Ar-H), 8.54(d,J=8.0Hz,2H,Ar-H), 10.47(brs,1H,OH) IR(KBr) cm -1 : 3431(OH), 1668(C=O), 1602, 1483, 1319, 1227 MS m/z: 323(M + ) Elementary analysis (C 15 H 8 F 3 NO 2 S 0.25H 2 O): Calculated (C=54.96,H=2.61,N=4.27); Found (C=55.31,H=2.47,N=3.90) tert-Butyl 4-(6-hydroxy-2-benzothiazolecarbonyl)phenoxyacetate (Compound 46) mp: 156-157 °C 1 H-NMR(DMSO-d 6 ): 1.47(s,9H,CH 3 ), 4.85(s,2H,CH 2 ), 7.13-7.16(m,3H,Ar-H), 7.52(d,J=2.4Hz,1H,Ar-H), 8.10(d,J=9.0Hz,1H,Ar-H), 8.51(d,J=9.0Hz,2H,Ar-H), 10.42(brs,1H,OH) IR(KBr) cm -1 : 3442(OH), 1755(C=O), 1736, 1601(C=O), 1489, 1228 MS m/z: 385(M + ) Elementary analysis (C 20 H 19 NO 5 S): Calculated (C=62.32,H=4.97,N=3.63); Found (C=62.28,H=4.90,N=3.93) 4-(6-Hydroxy-2-benzothiazolecarbonyl)phenoxyacetic Acid (Compound 47) mp: 216-217 °C 1 H-NMR(DMSO-d 6 ): 4.86(s,2H,CH 2 ), 7.29(dd,J=9.2,2.4Hz,1H,Ar-H), 7.87(d,J=2.4Hz,1H,Ar-H), 8.18(d,J=9.0Hz,1H,Ar-H), 8.44(d,J=8.6Hz,2H,Ar-H), 8.58(d,J=8.6Hz,2H,Ar-H), 10.37(brs,1H,OH), 13.13(brs,1H,COOH) IR(KBr) cm -1 : 3413(OH), 3074(OH), 1772(C=O), 1601(C=O), 1491, 1257 MS m/z: 329(M + ) Elementary analysis (C 16 H 11 NO 5 S 0.5H 2 O): Calculated (C=56.80,H=3.57,N=4.14); Found (C=56.73,H=3.50,N=4.26) 6-Methoxy-2-(4-nitrobenzoyl)benzothiazole (Compound 48) mp: 225-226 °C (decomp.) 1 H-NMR(DMSO-d 6 ): 3.91(s,3H,CH 3 ), 7.14(dd,J=9.0,2.2Hz,1H,Ar-H), 7.47-7.53(m,3H,Ar-H), 8.09(d,J=9.0Hz,1H,Ar-H), 8.37(d,J=8.2Hz,2H,Ar-H) IR(KBr) cm -1 : 1641(C=O), 1601, 1525(NO 2 ), 1354(NO 2 ) MS m/z: 314(M + ) Elementary analysis (C 15 H 10 N 2 O 4 S): Calculated (C=57.32,H=3.21,N=8.91); Found (C=57.16,H=3.13,N=9.25) 6-Methoxy-2-(3-nitrobenzoyl)benzothiazole (Compound 49) mp: 156-157 °C (decomp.) 1 H-NMR(DMSO-d 6 ): 3.92(s,3H,CH 3 ), 7.29(dd,J=9.2,2.6Hz,1H,Ar-H), 7.87(d,J=2.6Hz,1H,Ar-H), 7.94(dd,J=9.2,9.0Hz,1H,Ar-H), 8.20(d,J=9.0Hz,1H,Ar-H), 8.58(dd,J=8.2,2.0Hz,1H,Ar-H), 8.81(d,J=7.8Hz,1H,Ar-H), 9.21(d,J=2.0Hz,1H,Ar-H) IR(KBr) cm -1 : 1647(C=O), 1603, 1527(NO 2 ), 1491, 1356(NO 2 ) MS m/z: 314(M + ) Elementary analysis (C 15 H 10 N 2 O 4 S): Calculated (C=57.32,H=3.21,N=8.91); Found (C=57.28,H=3.29,N=9.07) 2-(3-Fluorobenzoyl)-6-hydroxybenzothiazole (Compound 50) mp: 162-163 °C (decomp.) 1 H-NMR(DMSO-d 6 ): 7.15(d,J=8.6Hz,1H,Ar-H), 7.53(s,1H,Ar-H), 7.36(dd,J=7.2,7.2Hz,1H,Ar-H), 7.69(dd,J=7.2,6.2Hz,1H,Ar-H), 8.12(d,J=8.6Hz,1H,Ar-H), 8.21(d,J=9.2Hz,1H,Ar-H), 8.27(d,J=7.2Hz,1H,Ar-H), 10.44(brs,1H,OH) IR(KBr) cm -1 : 3433(OH), 1629(C=O), 1581, 1482, 1256, 841 MS m/z: 273(M + ) 2-[3-t-Butyl-4-(2-methoxyethoxy)methoxy]benzoyl-6-(2-methoxyethoxy)methoxybenzothiazole (Compound 51) 1 H-NMR(DMSO-d 6 ): 1.45(s,9H,CH 3 ), 3.30-3.42(m,6H,CH 3 ), 3.55-3.64(m,4H,CH 2 ), 5.38(s,2H,CH 2 ), 5.44(s,2H,CH 2 ), 7.22-7.32(m,3H,Ar-H), 7.67(d,J=2.4Hz,1H,Ar-H), 8.09(d,J=9.0Hz,1H,Ar-H), 8.53(d,J=7.0Hz,1H,Ar-H) IR(neat) cm -1 : 2925, 1637(C=O), 1592, 1489, 1216 5-Trifluoromethyl-2-(4-hydroxybenzoyl)benzothiazole (Compound 52) mp: 234.5-236 °C 1 H-NMR(DMSO-d 6 ): 6.99(d,J=8.8Hz,2H,Ar-H), 7.95(d,J=8.4Hz,1H,Ar-H), 8.50(d,J=8.8Hz,2H,Ar-H), 8.52(d,J=8.4Hz,1H,Ar-H), 8.66(s,1H,Ar-H), 10.81(brs,1H,OH) IR(KBr) cm -1 : 3275(OH), 1622(C=O), 1566, 1491, 1323, 1292, 1174, 1122 MS m/z: 323(M + ) 6-Chloro-2-(4-hydroxybenzoyl)benzothiazole (Compound 53) mp: 209-210 °C 1 H-NMR(DMSO-d 6 ): 6.97(d,J=8.8Hz,2H,Ar-H), 7.70(dd,J=8.8,2.0Hz,1H,Ar-H), 8.28(d,J=8.8Hz,1H,Ar-H), 8.44(d,J=2.0Hz,1H,Ar-H), 8.47(d,J=8.8Hz,2H,Ar-H), 10.80(brs,1H,OH) IR(KBr) cm -1 : 3383(OH), 1605(C=O), 1572, 1485, 1300, 1134 MS m/z: 291(M + , 37 Cl), 289(M + , 35 Cl) Elementary analysis (C 14 H 8 ClNO 2 S): Calculated (C=58.04,H=2.78,N=4.83); Found (C=58.20,H=2.68,N=5.09) 6-Acetamido-2-(4-hydroxybenzoyl)benzothiazole (Compound 54) mp: 226-227 °C 1 H-NMR(DMSO-d 6 ): 2.13(s,3H,CH 3 ), 6.85(dd,J=8.8Hz,2H,Ar-H), 7.76(d,J=9.0Hz,Ar-H), 8.17(d,J=9.0Hz,1H,Ar-H), 8.43(d,J=8.8Hz,2H,Ar-H), 8.62(s,1H,Ar-H), 10.39(brs,1H,OH) IR(KBr) cm -1 : 3323(OH), 3155(NH), 1678(C=O), 1601(C=O), 1572, 1514, 1489, 1296 MS m/z: 312(M + ) 5-Chloro-2-(4-hydroxybenzoyl)benzothiazole (Compound 55) mp: 223-225 °C (decomp.) 1 H-NMR(DMSO-d 6 ): 6.98(d,J=8.6Hz,2H,Ar-H), 7.70(d,J=8.4Hz,1H,Ar-H), 8.31(d,J=8.4Hz,1H,Ar-H), 8.39(s,1H,Ar-H), 8.47(d,J=8.6Hz,2H,Ar-H), 10.79(brs,1H,OH) IR(KBr) cm -1 : 3323(OH), 1606(C=O), 1597, 1562, 1489, 1302, 1124 MS m/z: 291(M + , 37 Cl), 289(M + , 35 Cl) Elementary analysis (C 14 H 8 ClNO 2 S): Calculated (C=58.04,H=2.78,N=4.83); Found (C=58.31,H=3.14,N=4.93) 2-(4-Hydroxybenzoyl)-6-methylbenzothiazole (Compound 56) mp: 210-212 °C 1 H-NMR(DMSO-d 6 ): 2.51(s,3H,CH 3 ), 6.98(d,J=8.4Hz,2H,Ar-H), 7.48(d,J=8.2Hz,1H,Ar-H), 8.03(s,1H,Ar-H), 8.15(d,J=8.2Hz,1H,Ar-H), 8.48(d,J=8.4Hz,2H,Ar-H), 10.71(brs,1H,OH) IR(KBr) cm -1 : 3333(OH), 1628, 1597(C=O), 1491, 1299, 1170 MS m/z: 269(M + ) Elementary analysis (C 15 H 11 NO 2 S): Calculated (C=66.90,H=4.12,N=5.20); Found (C=66.85,H=4.16,N=5.05) 2-(4-Hydroxybenzoyl)-4-methylbenzothiazole (Compound 57) mp: 186-187 °C (decomp.) 1 H-NMR(DMSO-d 6 ): 2.51(s,3H,CH 3 ), 6.98(d,J=8.4Hz,2H,Ar-H), 7.48(d,J=8.2Hz,1H,Ar-H), 8.03(s,1H,Ar-H), 8.15(d,J=8.2Hz,1H,Ar-H), 8.48(d,J=8.4Hz,2H,Ar-H), 10.71(brs,1H,OH) IR(KBr) cm -1 : 3348(OH), 1627, 1579(C=O), 1488, 1296, 1171, 1117 MS m/z: 269(M + ) Elementary analysis (C 15 H 11 NO 2 S): Calculated (C=66.90,H=4.12,N=5.20); Found (C=67.12,H=4.16,N=5.36) 4-Hydroxy-2-(4-hydroxybenzoyl)benzothiazole (Compound 58) mp: 213-214 °C 1 H-NMR(DMSO-d 6 ): 6.96-7.02(m,3H,Ar-H), 7.45(t,J=7.2,7.2Hz,1H,Ar-H), 8.58(d,J=7.2Hz,1H,Ar-H), 8.59(d,J=7.2Hz,2H,Ar-H), 10.62(brs,2H,OH) IR(KBr) cm -1 : 3397(OH), 3267(OH), 1616, 1603(C=O), 1569, 1470, 1282 MS m/z: 271(M + ) 2-(4-Hydroxybenzoyl)-4-methoxybenzothiazole (Compound 59) mp: 209-210 °C (decomp.) 1 H-NMR(DMSO-d 6 ): 4.04(s,3H,CH 3 ), 6.98(d,J=7.0Hz,2H,Ar-H), 7.17(d,J=7.2Hz,1H,Ar-H), 7.58(dd,J=8.2,7.2Hz,1H,Ar-H), 7.76(d,J=8.2Hz,1H,Ar-H), 8.78(d,J=8.2Hz,2H,Ar-H), 10.72(brs,1H,OH) IR(KBr) cm -1 : 3407(OH), 1638(C=O), 1580, 1570, 1566, 1301, 1115, 901 MS m/z: 285(M + ) 4-Chloro-2-(4-hydroxybenzoyl)benzothiazole (Compound 60) mp: 242-243 °C (decomp.) 1 H-NMR(DMSO-d 6 ): 7.00(d,J=8.8Hz,2H,Ar-H), 7.63(dd,J=8.2,8.6Hz,1H,Ar-H), 7.78(dd,J=7.6,0.8Hz,1H,Ar-H), 8.24(dd,J=8.2,0.8Hz,1H,Ar-H), 8.52(d,J=8.8Hz,2H,Ar-H), 10.72(brs,1H,OH) IR(KBr) cm -1 : 3341(OH), 1597(C=O), 1566, 1492, 1179, 895, 762 MS m/z: 291(M + , 37 Cl), 289(M + , 35 Cl) 6-Fluoro-2-(4-hydroxybenzoyl)benzothiazole (Compound 61) mp: 174-175 °C 1 H-NMR(DMSO-d 6 ): 6.99(d,J=8.8Hz,2H,Ar-H), 7.56(ddd,J=9.0,8.8,2.6Hz,1H,Ar-H), 8.18(dd,J=8.8,2.6Hz,1H,Ar-H), 8.33(dd,J=9.0,5.0Hz,1H,Ar-H), 8.49(d,J=8.8Hz,2H,Ar-H), 10.74(brs,1H,OH) IR(KBr) cm -1 : 3364(OH), 1625, 1594(C=O), 1491, 1301, 1245, 871 MS m/z: 273(M + ) 6-Methoxy-2-(4-methoxycarbonylbenzoyl)benzothiazole (Compound 62) mp: 189.5-190 °C 1 H-NMR(DMSO-d 6 ): 3.91(s,3H,CH 3 ), 3.93(s,3H,CH 3 ), 7.28(d,J=8.0Hz,1H,Ar-H), 7.86(s,1H,Ar-H), 8.06(d,J=8.0Hz,1H,Ar-H), 8.18(d,J=7.6Hz,2H,Ar-H), 8.50(d,J=7.6Hz,2H,Ar-H) IR(KBr) cm -1 : 1727(C=O), 1638(C=O), 1604, 1491, 1229 2-(4-Carboxybenzoyl)-6-methoxybenzothiazole (Compound 63) mp: 260-261 °C (decomp.) 1 H-NMR(DMSO-d 6 ): 3.91(s,3H,CH 3 ), 7.27(d,J=8.0Hz,1H,Ar-H), 7.85(s,1H,Ar-H), 8.13(d,J=7.6Hz,2H,Ar-H), 8.18(d,J=8.0Hz,1H,Ar-H), 8.44(d,J=7.6Hz,2H,Ar-H) IR(KBr) cm -1 : 3440(OH), 1643(C=O), 1604(C=O), 1491, 1407, 1255, 1228 [Function] Pharmacological actions of the compounds of the present invention are as follows. (1) Lipid lowering action Streptozotocin (45 mg/kg) was intravenously administered to Wistar-strain male rats (5 weeks of age). After a week, the rats whose blood glucose levels increased to 240-300 mg/dl were selected and divided uniformly into groups (8 rats/group). The tested drugs (100 mg/kg/day) were orally administered for 3 weeks and blood was collected from the orbita vein. Cholesterol, triglyceride and low-density lipoprotein in the blood sample were measured. An example of the results is shown in Table 1. The unit of each value is mg/dl and the standard deviation is given as an additional remark. Control Compound 7 Cholesterol 956.6±234.4 260.8±209.4 Triglyceride 380.9±161.8 161.4±156.5 Low-density lipoprotein 2988±1387 404±708 As apparently shown by the above-mentioned results of pharmacological studies, the benzothiazole derivatives of the present invention have excellent pharmacological activities which significantly decrease cholesterol, triglyceride and low-density lipoprotein in blood. Therefore, they are novel compounds which are very useful as medicines such as a remedy for hyperlipemia.

Claims: A benzothiazole derivative represented by the general formula (I) or a pharmaceutically acceptable salt thereof: wherein R 1 is halogen, C 1-6 alkyl, trifluoromethyl, acetamide or -OX 1 ; X 1 is hydrogen, C 1-6 alkyl or C 1-6 acyl; R 2 is hydrogen, halogen, C 1-6 alkyl, hydroxyC 1-6 alkyl, trifluoromethyl, nitro, amino which may be substituted with C 1-6 alkyl or C 1-6 acyl, carboxy which may be esterified with C 1-6 alkyl, or -OX 2 ; X 2 is hydrogen, C 1-6 alkyl, C 1-6 acyl, carboxyC 1-6 alkyl which may be esterified with C 1-6 alkyl; or n is an integer from 1 to 3 which means a number of substituent R 2 ; and plural R 2 may be the same or different when n is 2 or 3; with the proviso that R 1 is a group other than chloride when R 2 is hydrogen. A benzothiazole derivative according to claim 1 wherein R 1 is -OX 1 . A benzothiazole derivative according to claim 2 wherein X 1 is hydrogen. A benzothiazole derivative according to claim 2 wherein X 1 is C 1-6 alkyl. A benzothiazole derivative according to any of the claims 1-4 wherein n is 1. A benzothiazole derivative according to any of the claims 1-5 wherein R 2 is -OX 2 . A benzothiazole derivative according to claim 6 wherein X 2 is hydrogen. A benzothiazole derivative according to claim 6 wherein X 2 is C 1-6 alkyl. 2-(4-hydroxybenzoyl)benzothiazole or a pharmaceutically acceptable salt thereof. A pharmaceutical composition comprising a benzothiazole derivative or a salt thereof as defined in any of the claims 1-9 and a pharmaceutically acceptable carrier. Use of a benzothiazole derivative or a pharmaceutically acceptable salt thereof as defined in any of the claims 1-10 for preparing a lipid lowering medicament.

Inventors: FUKUDA KIYOSHI, HASEGAWA TAISUKE, KOTANI TAKAYUKI, MURAMOTO HIROKI, OKAMOTO KAORU, FUKUDA, KIYOSHI, HASEGAWA, TAISUKE, KOTANI, TAKAYUKI, MURAMOTO, HIROKI, OKAMOTO, KAORU, Fukuda, Kiyoshi, c/o Ono Greenery Factory, Hasegawa, Taisuke Institute of Bio-Active Science, Kotani, Takayuki, Institute of Bio-Active Science, Muramoto, Hiroki, Nippon Zoki Pharm. Co., Ltd., Okamoto, Kaoru, Institute of Bio-Active Science
Applicants: NIPPON ZOKI PHARMACEUTICAL CO, NIPPON ZOKI PHARMACEUTICAL CO., LTD.
Application year: 1996
Main classification: C07D277
IPC codes: C07D277