Facile Synthesis of Novel Functionalized Pyridine Annulated Oxirane Methyl Coumarins

Abstract

A one‐pot synthesis of series of new ethyl‐7‐oxirane methyl‐2‐methyl‐5‐oxo‐5H‐benzopyrano[3,4‐c]pyridine‐1‐carboxylates (6a–e) from 3‐allyl‐2‐hydroxy acetophenones (1a–e) via key intermediate 8‐allyl‐4‐chloro‐3‐formyl coumarins (2a–e) is described. The reaction involves Michael addition of 8‐allyl‐4‐chloro‐3‐formyl coumarins with ethyl 3‐amino crotonoate followed by cyclization, and per acid epoxidation proceeds under mild conditions and gives products in good‐to‐excellent yields.