Nano TiO2–H3BO3 as an efficient and recycable catalyst for the synthesis of 5-substituted-1H-tetrazoles

Abstract

An efficient method for the synthesis of 5-substituted-1<em>H</em>-tetrazoles through the reaction of nitriles with sodium azide using titanium oxide–supported boric acid (TiO₂-H₃BO₃) catalyst was reported. The reactions were carried out at 120 °C and provided the corresponding tetrazoles in good to excellent yields. This method displayed significant advantages such as stability of the catalyst, high product yield, simple methodology, and easy work up. Also, this catalyst can be reused several times without loss of its catalytic activity. The aromatic nitriles with electron-donating and electron-withdrawing groups could be accomplished. The structural characteristics of the catalyst were identified by FT-IR, powder X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) and inductively coupled plasma (ICP) analyses.