| abstract |
Synthetic intermediate for benzoimidazole compound or its salt which possesses excellent action to reduce blood-glucose and preparation thereof are provided. A preparation for preparing benzoimidazole compound (I) which is characterized by condensing amine derivative (III) with carboxylic acid derivative (II) as formula, (wherein, R1 is C1-C6 alkyl group or C1-C6 alkoxy group, etc, R2 is C1-C6 alkyl group, R3 is hydrogen atom or protective group) into compound (IV), and closing the ring in the presence of acid. |