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

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.

Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (80 K)Download as PowerPoint slideHighlights► Adding ionic liquid to H3PW12O40 and K4W10O32. ► Heterogeneous catalysts were prepared. ► These catalysts were active in the synthesis of azlactones. ► Makes the catalyst reusable.