INTERMEDIATE FOR SYNTHESIZING BENZIMIDAZOLE COMPOUND AND ITS PRODUCTION

摘要

PROBLEM TO BE SOLVED: To obtain a new nitrophenyl group-containing compound which is useful as an intermediate for synthesizing a benzimidazole compound having an excellent hypoglycemic action. SOLUTION: A compound of formula I (R1a to R4a are each H, OH, a 1 to 6C alkyl or the like; R5a and R6a are each an amino-protecting group), for example, t-butyl N-(5-methoxy-2-nitrophenyl)-N-t-butoxycarbonylcarbamate. The compound of formula I is obtained by reacting a compound of formula II with an amino-protecting group-introducing reagent in the presence of a base [for example, 4-(N,N-dimethylamino)pyridine] preferably in an amount of 0.02 to 0.1 equivalent in an inactive solvent (for example, methylene chloride). The amino-protecting group-introducing reagent is preferably an amino- protecting group-having halide or an acid anhydride, such as di-t-butoxycarbonyl dicarbonate. The reaction temperature is preferably 0 to 50 deg.C, and the reaction time is preferably 30 min to 5 hr.