Nano-Structured Pyrophosphate Na2CaP2O7 as Catalyst for Selective Synthesis of 1,2-Disubstituted Benzimidazoles in Pure Water

We report on synthesis of 1,2-disubstituted benzimidazoles in pure water using nano-structured pyrophosphate Na2CaP2O7. Our findings showed that this heterogeneous catalyst exhibited high catalytic activity and high selectivity in the synthesis of 1,2- disubstituted benzimidazoles from direct cyclocondensation of aromatic aldehydes with substituted benzene-1,2-diamine in pure water. The salient benefits of this method rely on various factors namely: a simple procedure, mildness of the reaction conditions, short reaction times, operational simplicity, high chemoselectivity, low cost and recyclability of the catalyst.