regioselective transmonocyanoacetylation of o-phenylenediamine derivatives: simple and efficient synthesis of 2-cyanomethylbenzimidazole derivatives

A simple and efficient method for the regioselective transmonocyanoacetylation of o-phenylenediamine derivatives was developed using 1-cyanoacetyl-3,5-dimethylpyrazole as a cyanoacetylating agent. this method provided operationally simple and efficient access to a series of n-(2-aminophenyl)-2-cyanoacetamide derivatives under mild conditions with short reaction time. also, 2-cyanomethylbenzimidazole derivatives have been synthesized through the cyclocondensation of n-(2-aminophenyl)-2-cyanoacetamide derivatives. in all cases, high yield of products was obtained and reaction times were significantly reduced with relation to similar reactions.