Three-component solvent-free synthesis of 5-substituted-1H-tetrazoles catalyzed by unmodified nanomagnetite with microwave irradiation or conventional heating

Abstract

A convenient, rapid, and highly efficient procedure for synthesis of 5-substituted-1H-tetrazoles was developed via multicomponent domino Knoevenagel condensation/1,3-dipolar cycloaddition reaction between aromatic aldehydes, malononitrile, and sodium azide in presence of Fe3O4 magnetic nanoparticles, using microwave irradiation and conventional heating, under solvent-free conditions. The procedure is efficient due to the low cost and nontoxicity of the catalyst, elimination of volatile and toxic solvents, very short reaction time, excellent product yield, easy methodology, and simple workup. The magnetite catalyst was recycled using an external magnet and could be reused in at least five consecutive runs, delivering high product yield. We illustrate that green, efficient, and recoverable Fe3O4 magnetic nanoparticles can catalyze Knoevenagel condensation/1,3-dipolar cycloaddition of aromatic aldehydes, malononitrile, and NaN3 to synthesize 5-substituted-1H-tetrazoles using microwave irradiation and conventional heating.