Microwave irradiation synthesis of 2-substituted benzimidazoles using PPA as a catalyst under solvent-free conditions

An efficient microwave irradiation synthesis of 2-substituted benzimidazoles using polyphosphoric acid (PPA) as a catalyst from organic acid and o-phenylenediamine under solvent-free conditions is described. This method is a good option to obtain the title compounds in a simple and an inexpensive way.