Silica-supported molybdic acid: preparation, characterization, and its catalytic application in synthesis of pyranocoumarins

摘要

Silica-supported molybdic acid was employed as novel, recyclable, and safe catalyst in a one-pot three-component condensation of aldehydes, malononitrile, and 4-hydroxycoumarin to produce new and known pyrano[2,3-c]chromenes as potent biologically active compounds. This expedient new route has advantages, such as the use of a safe and reusable catalyst, simple operation, short reaction times, and good to excellent yields. The silica-supported molybdic acid as a novel solid acid was characterized by X-ray fluorescence, X-ray diffraction, and Fourier transform infrared spectroscopy.