Synthesis of nitrogen rich 5-substituted-1H-tetrazoles using a heterogeneous magnetic catalyst based on zirconium

Tetrazoles are an important class of nitrogen-rich heterocycles which have a wide range of applications in high energy materials, pharmaceutical industries, treatment of various disease, biochemistry, bioimaging, and photography. In this paper, Zr0.25Zn0.25Cu0.5Fe2O4 catalyst was first synthesized by two common combustion and hydrothermal methods and was then characterized by inductively coupled plasma atomic emission spectroscopy (ICP-AES), X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM) methods. Furthermore, this catalyst has the magnetic properties. The catalytic activity of the Zr0.25Zn0.25Cu0.5Fe2O4 heterogeneous magnetic catalyst was investigated for the synthesis of a wide range of 5-substituted-1H-tetrazole derivatives via [3+2] cycloaddition of sodium azide with various nitriles in N,N-dimethylformamide at 120 °C. The main advantages of this method are high efficiency, simple methodology, easy work-up and catalyst reusability. Furthermore, this catalyst can be easily separated from the reaction mixture using an external magnet and reused for five cycles without a significant decrease in its catalytic activity.