Multi-component one-pot synthesis of tetrasubstituted pyrroles by silica molybdic acid under solvent-free conditions

A variety of tetrasubstituted pyrroles were synthesized by a one-pot three-component reaction of α-hydroxyketones (benzoin derivatives), malononitrile, and ammonium acetate in good yields under solvent-free conditions. In these reactions silica molybdic acid (SMA) was used as efficient, reusable, green and useful catalyst. The prepared silica molybdic acid (SMA) was characterized by X-ray fluorescence (XRF), powdered X-ray diffraction (XRD), and FT-IR spectroscopy. The attractive advantages of this method are the short reaction times, high yields of the products and reusability of the catalyst. All of these advantages make it a useful strategy for the preparation of various pyrrole derivatives simply by different substrates.