文献类型：专利

英文题名：Preparing 2,2,2-trifluoroethyl benzo(d)(1,2,3)thiadiazole-7-carboxylate, comprises reacting 3-aminobenzoic acid with methanol, adding thiocyanate, adding e.g. bromine, performing ring-opening, diazotization and ring-closure and esterifying

作者：QIAN X;XU Y;ZHOU J;ZHU W;ZHAO Z;CHEN M

机构：[1]UNIV EAST CHINA SCI&TECHNOLOGY

申请号：CN101973960-B

公开日：2012-07-04

语种：英文

收录：DERWENT

摘要：NOVELTY - Preparing 2,2,2-trifluoroethyl benzo(d)(1,2,3)thiadiazole-7-carboxylate, comprises esterifying 3-aminobenzoic acid with methanol to obtain methyl 3-aminobenzoate, reacting with a thiocyanate to obtain methyl 2-thioureidobenzoate, adding e.g. bromine or glacial acetic acid to obtain methyl 2-aminobenzo(d)thiazole-7-carboxylate, heating in an aqueous solution of potassium hydroxide for ring-opening reaction, carrying out diazotization and ring-closure to obtain benzo(d)(1,2,3)thiadiazole-7-carboxylic acid and esterifying benzo(d)(1,2,3)thiadiazole-7-carboxylic acid with trifluoroethanol. USE - The method is useful for preparing 2,2,2-trifluoroethyl benzo(d)(1,2,3)thiadiazole-7-carboxylate. ADVANTAGE - The method increases the yield of the product, in comparison with the conventional method. DETAILED DESCRIPTION - Preparing 2,2,2-trifluoroethyl benzo(d)(1,2,3)thiadiazole-7-carboxylate, comprises: (i) esterifying 3-aminobenzoic acid with methanol to obtain methyl 3-aminobenzoate; (ii) reacting methyl 3-aminobenzoate with a thiocyanate in the presence of a surfactant to obtain methyl 2-thioureidobenzoate; (iii) adding bromine, chlorobenzene or glacial acetic acid for cyclization reaction to obtain methyl 2-aminobenzo(d)thiazole-7-carboxylate; (iv) heating methyl 2-aminobenzo(d)thiazole-7-carboxylate in an aqueous solution of potassium hydroxide for ring-opening reaction, and carrying out diazotization reaction and ring-closure under acidic conditions to prepare benzo(d)(1,2,3)thiadiazole-7-carboxylic acid; and (v) esterifying benzo(d)(1,2,3)thiadiazole-7-carboxylic acid with trifluoroethanol in the presence of an esterification agent to obtain the product, where the esterification agent is oxalyl chloride.