Syntheses of Some Benzimidazoles from N-Arylamidines

Grenda's method to convert arylamidine hydrochloride into benzimidazole with the aid of sodium hypochloride and a base has been applied to the previously untried N-arylamidines to synthesize the following : 5-chloro-2-phenylbenzimidazole (Y=96%), 5-methyl-2-phenylbenzimidazole (Y=96%), 2-benzylbenzimidazole (Y=50%), 2-benzyl-5-chlorobenzimidazole (Y=70%), 2-(2'-naphthyl)-benzimidazole (Y=75%), 5-chloro-2-(2'-naphthyl)-benzimidazole (Y=90%), 2-(p-tolyl)-benzimidazole (Y=95%), 5-chloro-2-(p-tolyl)-benzimidazole (Y=80%), 5-methyl-2-(p-tolyl)-benzimidazole (Y=80%).