Synthesis of Schiff Bases by Non-Conventional Methods

Abstract

A Schiff base is a compound with the general structure R1R2C=NR’. They can be considered a subclass of imines. The term Schiff base is normally applied when these compounds are used as ligands to form coordination complexes with metal ions. Schiff bases can be synthesised from a primary aliphatic or aromatic amine and a carbonyl compound by nucleophilic addition forming a hemiaminal, followed by a dehydration to generate an imine. In other words, a Schiff base is a nitrogen analogue of a ketone or aldehyde where the carbonyl group has been replaced by azomethine or imine group. The imine group present in these compounds has been shown to be critical to their biological activities. Schiff bases have been frequently used in various fields such as medicine, pharmaceutical purposes due to their wide range of industrial applications. The unconventional methods of preparation of Schiff bases, compared with traditional methods, are more convenient, and reactions can be carried out in higher yield, shorter reaction time and milder conditions, without generation of pollution and safer to analyse.