Highly efficient synthesis of 1- and 5-substituted 1H-tetrazoles using chitosan derived magnetic ionic liquid as a recyclable biopolymer-supported catalyst

Abstract

A general method for the efficient synthesis of 1- and 5-substituted 1H-tetrazoles from nitriles and amines is described using chitosan supported magnetic ionic liquid nanoparticles (CSMIL) as a novel heterogeneous catalyst. The application of this catalyst allows the synthesis of a variety of tetrazoles in high yields at low temperature. This new magnetic catalyst has been prepared from chitosan (the most abundant biopolymer in nature and cheap industrial waste) and methyl imidazole (a widely available backbone of ionic liquids) which was reacted with FeCl₃ to obtain the CS–EMImFeCl₄ catalyst. This methodology illustrates a very simple procedure, with wide applicability, environmental friendliness and reusability of catalyst. The new catalyst was characterized using some different microscopic and spectroscopic techniques such as transmission electron microscopy (TEM), scanning electron microscopy (SEM), FTIR spectroscopy, and Raman spectroscopy. The novel catalyst has therefore a great potential to be used in green processes.