DABCO-catalyzed highly regioselective synthesis of novel 4H-pyrano[2,3- b]quinoline derivatives: three‑component domino strategy

Abstract

A highly regioselective multicomponent synthesis via DABCO-mediated knoevenagel condensation/heterocyclization sequence has been executed. An efficient and fast-track protocol has been used for preparing O-heterocyclic compounds under metal-free conditions. The one pot three-component reaction of 2-chloroquinoline-3-carbaldehyde and two diverse cyclic active methylenes (dimedone and barbituric acid) for the synthesis of 4H-pyrano[2,3-b]quinoline has been accomplished under mild condition. The strategy included herein shows significant advantages including a facile process with easy purification, excellent yields, wide applicability, available substrates and cost-effective and eco-friendly solvent and catalyst.