Fe3O4 nanoparticles: An efficient and recyclable catalyst for benzimidazoles synthesis

A facile technique for the condensation of o-phenylenediamine and aromatic aldehydes to benzimidazole derivatives in the presence of nano-sized Fe3O4 particles has been studied. The reactions were conducted under a mild condition. The compound 3a-c was obtained in high yields, and the catalyst could be readily separated by an ordinary external magnet from the mixture of reaction. This protocol has many advantages such as the use of recoverable magnetic nanocatalyst, a relatively short reaction time, high yields, and simple to be implemented in a larger scale.