An Atom Economical Concise Green Synthetic Protocol for the Synthesis of 4-Substituted Benzylidene β-Lactams Easy Access by P2O5/SiO2 Catalyzed Schiff Base

Abstract

A simple and efficient protocol for the synthesis of Schiff bases via condensation reaction of electron rich heterocyclic amines with electrophilic carbon of the carbonyl compound. Recently an impressive and important area in catalysis involved organic synthesis is the best implementation of Lewis acids as a acid catalyst for Schiff base synthesis. The higher acidic property and proper loading of catalyst leads to proper participation in reaction as a catalyst. The reactions of these Lewis acids are enhanced by porous solid support as heterogeneous catalyst. We report herein an efficient concise green synthesis of a new kind of β-lactam derivatives of 2-amino-6-nitro-benzothiazole via SiO2/P2O5 Lewis acid catalyzed Schiff bases. The reaction was carried out by the preparation of Schiff base through the condensation reaction of various aromatic aldehydes with substituted aromatic amines in the presence of P2O5/SiO2 under green conditions by simple conventional methods. Further this Schiff base used for the green synthesis of β-lactams by the reaction with chloro-acetyl chloride. The advantage of this reaction is good dispersion of active reagent sites, associated selectivity and easier work up with reusable catalyst. These qualities combined together prove these processes as truly eco-friendly green protocol with high product yields and short reaction time.