Silica Supported MTSA Catalyst for the Synthesis of 5-Substituted-1H-tetrazole- A Green Chemistry Approach

We have developed simple, cost efficient and environmentally benign protocol for the synthesis of 5-substituted 1H-tetrazole via [2+3] cyclo addition reaction from organic nitrile and sodium azide in refluxing DMF by using heterogeneous catalyst as MTSA (Melamine tri sulphonic acid). The corresponding 5-substituted 1H-tetrazole were obtained in lower yield but when using silica supported MTSA the yield obtained 85% in 6 h. After completion of the reaction, the catalyst was recovered by filtration and reused with only a slight decrease of activity observed under the same reaction conditions. Various aliphatic and aromatic nitrile converted in corresponding 5-substituted 1H-tetrazole in excellent yield without any contamination.