PREPARATION OF 2-(3'- OR 4'-AMINOPHENYL)-5(OR 6)-AMINOBENZIMIDAZOLES

摘要

A process for the production of wherein R1 and R2 are the same or different and each is hydrogen, alkyl having 1-4 carbon atoms, alkoxy having 1-4 carbon atoms, chlorine or bromine, and n is 1 or 2 comprising reacting at -10 DEG C. to 100 DEG C. at a pH of from 1-10 to form an anilide of the formula and cyclizing and reducing the anilide in an aqueous alkaline medium with a sulfide reducing agent.