Organic-inorganic hybrid polyoxometalates: Efficient, heterogeneous and reusable catalysts for solvent-free synthesis of azlactones

Abstract

Two organic-inorganic hybrid polyoxometalates, consist of 1-butyl-3-methylimidazolium salts of (W10O32)4- and (PW12O40)3- polyanions were prepared and characterized by thermal analysis, X-ray diffraction, FT-IR, diffuse reflectance UV-Vis spectroscopic methods and nitrogen absorption-desorption determination (BET). These heterogeneous catalysts were used for synthesis of azlactones by the reaction of aldehydes with hippuric acid and acetic anhydride under solvent-free conditions. These catalysts were reused several times without loss of their activities. © 2011 Elsevier B.V. All rights reserved.