The mineral alum: an effective and low-cost heterogeneous catalyst for the successful synthesis of 5-substituted-1H-tetrazoles

Abstract

A simple, efficient, and green procedure for the synthesis of 5-substituted-1H-tetrazoles via [3 + 2] cycloaddition reaction of nitriles with sodium azide is described. The reaction was catalyzed by natural and mesoporous alum nanoparticles (NPs) in DMSO at 140 °C. Alum NPs have been prepared as the new catalytic system by heating and calcination of mineral alum in a furnace. Alum NPs were characterized using FT-IR, BET, SEM-EDS, XRD, and TGA analysis. The results showed that alum, as an amorphous mineral and natural low-cost heterogeneous catalyst, provides 5-substituted-1H-tetrazoles easily with high efficiency. Some of the advantages of this method are high yields of the desired product, short reaction times, the safe catalyst, prevention of using the toxic metal catalysts, readily accessible of the catalyst, and low-cost heterogeneous catalyst.