Friedlander synthesis of novel benzopyranopyridines in the presence of chitosan as heterogeneous, efficient and biodegradable catalyst under solvent-free conditions

Abstract

Efficient synthesis of benzopyrano[4,3-b]pyridine derivatives was achieved from 4-amino-3-formylcoumarin and different active methylene compounds under solvent-free thermal heating at 80 °C via Friedlander condensation in the presence of chitosan as heterogeneous, basic green catalyst. The present methodology is a novel green approach to benzopyranopyridine. It offers several advantages such as shorter reaction time, mild reaction conditions, simple operational procedure, use of recyclable and biodegradable catalyst.