HClO4-SiO2 as an Efficient and Reusable Heterogeneous Catalyst for the Synthesis of 1-substituted Tetrazoles

An efficient and direct protocol is described for the preparation of 1-substituted 1H-1,2,3,4-tetrazoles by the reaction of primary amines, triethyl orthoformate and sodium azide in the presence of catalytic amount of silica-supported perchloric acid under solvent-free and heterogeneous conditions. The thermal solvent-free green procedure offers advantages such as simple methodology, easy work-up, high yield, recovery and reusability of catalyst.