| 摘要 |
1,184,489. Benzimidazoles. AGFA-GEVAERT A.G. 24 Nov., 1967 [25 Nov., 1966], No. 53521/67. Heading C2C. [Also in Division G2] Benzimidazoles of formula (in which R 1 is C 1-5 alkyl, cycloalkyl, alkoxyalkyl or hydroxyalkyl, R 2 is H, halogen, tert. amino or C 1-18 alkyl or alkoxy, R 3 is optionally substituted phenyl, naphthyl or quasi-aromatic heterocyclic, and R 4 is sulpho, aminosulphonyl, organosulphonyl or optionally esterified carboxyl), are prepared by reacting an aminophenyl-benzimidazole with an aroylacetic ester. In an example, Na-4-chloro-3-nitrobenzene sulphonate is refluxed with n-butylamine and NaHCO 3 to form 3 - nitro - 4- butylaminobenzene sulphonic acid which is reduced by Raney nickel to 3-amino-4-butylaminobenzene sulphonic acid, which is heated with 4-nitrobenzoylchloride in pyridine to form 2 - (4<SP>1</SP> - nitrophenyl) - 3 - butyl benzimidazole - 6- sulphonic acid which is reduced to 2-(4<SP>1</SP>-aminophenyl) 3 - butylbenzimidazole - 6 - sulphonic acid which is heated with p-cetyloxy-benzoylacetic ester in the presence of pyridine and triethylamine to form a benzimidazole in which R 1 is C 4 H 9 , R 2 is H, R 3 is p-C 6 H 4 -O-C 16 H 33 and R 4 is -SO 3 H. |
