Molybdic Acid-Functionalized Nano-Fe3O4@TiO2 as a Novel and Magnetically Separable Catalyst for the Synthesis of Coumarin-Containing Sulfonamide Derivatives.

Supported molybdic acid on nano-Fe3O4@TiO2 (Fe3O4@TiO2@(CH2)3OMoO3H) has been successfully prepared, char-acterized and applied as a catalyst for the synthesis of sulfonamide containing coumarin moieties. The prepared Fe3O4nanoparticles by coprecipitation of Fe2+ and Fe3+ ions were treated with tetraethyl orthotitanate to obtain Fe3O4@TiO2. By anchoring 3-chloropropyltriethoxysilan on Fe3O4@TiO2 followed by reacting with molybdic acid, the desired catalyst was produced.

Tungstic acid-functionalized FeO@TiO: preparation, characterization and its application for the synthesis of pyrano[2,3-]pyrazole derivatives as a reusable magnetic nanocatalyst.

A new magnetic nanocatalyst based on the immobilization of tungstic acid onto 3-chloropropyl-grafted TiO-coated FeO nanoparticles (FeO@TiO@(CH)OWOH) was prepared, characterized, and applied for the synthesis of pyrano[2,3-]pyrazole derivatives. The characterization was performed using FT-IR spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and vibrating sample magnetometry (VSM) analysis. Pyranopyrazoles were synthesized in the presence of this novel catalyst a three-component reaction of 3-methyl-1-phenyl-2-pyrazolin-5-one, malononitrile, and aromatic aldehydes with high yields.