Magnetic nanosphere Fe3O4@SiO2.SnCl4 promoted synthesis of 5-substituted 1H-tetrazoles

Tetrazoles have many interesting futures and applications in drug and energy industries. 5-Substituted 1H-tetrazoles were synthesized via [2+3] cycloaddition reaction of aryl or alkyl nitriles with sodium azide in the presence of Fe3O4@SiO2.SnCl4 as catalyst in DMF under reflux conditions. The catalyst was removed from reaction mixture by an external magnet and was reusable for many times without any appreciable loss of its activity. The Fe3O4@SiO2.SnCl4 promotes synthesis of tetrazole in shorter time than other reported catalysts. The obtained tetrazoles were identified by spectroscopic and physical data such as FT-IR, 1HNMR and melting point. Easy workup and reusability of catalyst are some advantages of this protocol.