Lanthanum‐Catalyzed One‐Pot Synthesis of Chromeno‐Fused Pyridine/Quinolinone Derivatives

A novel one‐pot approach has been developed for the preparation of 5‐oxo‐5H‐chromeno[4,3‐b]pyridine‐3‐carboxylates and 6H‐chromeno[4,3‐b]quinolin‐6‐ones by reacting 2‐((benzylimino/phenylimino)‐methyl)phenols with ethyl/methyl propiolate in presence of La(OTf)3 under thermal conditions. The reactions proceeded through the formation C‐O, C‐N and C‐C bonds to form the title compounds. The bio‐active compound 6H‐chromeno[4,3‐b]quinolin‐6‐one has been prepared by this protocol.