N-(2-CHLOROMETHYL-1-METHYL-1H-BENZIMIDAZOLE-5-ACYL)-N-(PYRIDINE-2-YL)-3-AMINOPROPANOIC ACID ETHYL ESTER PREPARATION METHOD

摘要

Disclosed is a dabigatran etexilate intermediate preparation method, the method comprising: a) utilizing 3-amino-4-methylaminobenzoic acid as a raw material for cyclization with chloroacetyl chloride to obtain 2-chloromethyl-1-methyl-1H-benzimidazole-5-carboxylic acid; b) the 2-chloromethyl-1-methyl-1H-benzimidazole-5-carboxylic acid is formed into 2-chloromethyl-1-methyl-1H-benzimidazole-5formyl chloride under the effect of oxalyl chloride; c) the 2-chloromethyl-1-methyl-1H-benzimidazole-5-formyl is condensed with 3-(pyridine-2-yl)aminopropanoic acid ethyl ester to obtain the N-(2-chloromethyl-1-methyl-1H-benzimidazole-5-acyl)-N-(pyridine-2-yl) -3-aminopropanoic acid ethyl ester. The synthetic route is not reported in any literature, and the raw material is cheap and easily available; in addition, the present invention has a simple unit operation and low equipment requirements, and is suitable for industrial mass production.