Multicomponent Synthesis of Pyrano (3, 2-c) Quinolone Fused Spirochromenes

A multicomponent pathway has been described for the synthesis of novel pyrano (3,2-c) quinolone fused spirochromenes by piperidine catalyzed reaction between isatins, phenyl (or alkyl) sulfonyl acetonitrile and 4-hydroxy-N-methylquinoline-2-one. Decent yields coupled with easy isolation of the products and avoidance of conventional purification methods are the noteworthy merits of the developed protocol.