Silica-Supported Molybdic Acid-Catalyzed Synthesis of New and Known Chromeno-Pyrano[2,3-b]Quinolines through a Green Route

A capable manner for the preparation of chromeno-pyrano[2,3-b]quinoline compounds is outlined. Pyrano[3,2-c]chromene-3-carbonitriles are synthesized via the one pot three-component reaction of aryl aldehydes, malononitrile and 4-hydroxycoumarin in the presence of silica sodium carbonate (SSC) as a heterogeneous basic catalyst. Next, the prepared pyrano[3,2-c]chromene-3-carbonitrile is reacted with cyclohexanone by using silica-supported molybdic acid (SSMA) as a worthy and recyclable catalyst for producing recognized and unrecognized chromeno-pyrano[2,3-b]quinoline derivatives under solvent-free conditions in good to excellent yields.