PROCESS FOR PRODUCING BENZIMIDAZOLE DERIVATIVE

摘要

A process for efficiently producing the following compound (X), which is useful as an intermediate for medicines, from the following compound (Y) while inhibiting by-product generation. The process, which is for producing a compound of the formula (X): (wherein R1 and R2 are the same or different and each represents hydrogen, methoxy, or difluoromethoxy; R3 represents methyl or methoxy; R4 represents methoxy, 2,2,2-trifluoroethoxy, or 3-methoxypropoxy; and R5 represents hydrogen or methyl), is characterized by comprising the following operations: adding an oxidizing agent to a compound of the formula (Y): in a water-immiscible organic solvent and reacting the ingredients to obtain a reaction mixture; adding an aqueous alkali solution to the reaction mixture obtained, shaking or stirring the resultant mixture at a pH of 13.0 or higher, and then allowing the mixture to stand and thereby separate into an organic layer (A1) and an aqueous layer (B1); and adding an oxidizing agent to the organic layer (A1) obtained and reacting the mixture.