Mellomprodukter for syntese av benzimidazolforbindelser, og fremgangsmåte for fremstilling derav

摘要

This invention provides a process for the preparation of a benzimidazole derivative (I) or a pharmaceutically acceptable salt thereof, wherein R<1> is C1-C6 alkyl, C1-C6 alkoxyl, etc., R<2> is C1-C6 alkyl, and R<3> is hydrogen or a protecting group, which exhibits excellent hyopoglycemic action, said process comprising condensation of an amine derivative (III) with a carboxylic acid derivatives (II) to afford a compound (IV), followed by cyclization of compound (IV) in the presence of an acid.