A heterogeneous mesoporous catalyst based on anchored copper: Schiff base complex into SBA-15 for the synthesis of benzimidazoles from orthoesters

Abstract

In this article, we report the synthesis of 2-substituted benzimidazoles via condensation of 1,2-phenylenediamines and orthoesters using a heterogeneous catalyst based on anchored copper-Schiff base complex into SBA-15 (Cu/SBA-15) as a modified nanoporous material. The catalyst has been prepared via a postsynthesis grafting method and the 2D hexagonal mesoporous structures of this hybrid have been confirmed by small-angle X-ray scattering, transmission electron microscopy, N2 adsorption–desorption isotherms and Fourier transform infrared spectroscopy. Our results show that the benzimidazole heterocycles were obtained in good to excellent yields under solvent-free conditions in the presence of entitled catalyst. The mesoporous silica pore walls of the catalyst create some advantages such as high specific surface area, good to excellent yields of the benzimidazole products, non-toxicity and reusability.