synthesis of benzimidazoles by two methods (c–h functionalization and condensation reaction) catalyzed by α-zirconium hydrogen phosphate-based nanocatalyst

In this report, two heterogeneous nanocatalysts based on α-zirconium hydrogen phosphate were applied. these heterogeneous catalysts have demonstrated the promising catalytic activity for the synthesis of 2-substituted benzimidazoles in two different methods. one of these reactions is the functionalization of the c–h bond and the formation of c–n bond, and the other reaction involves the condensation reaction between aldehydes and 1,2-phenylenediamine. the activity of both catalysts was compared in two methods, and the superior catalyst was introduced. the prepared catalysts are easily separated from the reaction mixture by centrifugation and reused several times without significant loss of activity.