Application of silica gel-supported polyphosphoric acid (PPA/SiO2) as a reusable solid acid catalyst to the synthesis of 3-benzoylisoxazoles and isoxazolines
3-Benzoylisoxazoles were synthesized by the reaction of alkynes and benzoylnitromethane using silica gel-supported polyphosphoric acid (PPA/SiO2). This reaction provides a convenient, efficient, and reusable synthetic method of isoxazole derivatives. (C) 2011 Elsevier Ltd. All rights reserved.
A Facile Approach to the Synthesis of 3-Acylisoxazole Derivatives with Reusable Solid Acid Catalysts
gel-supported sodium hydrogen sulfate (NaHSO4/SiO2) or Amberlyst 15 as solid acid catalyst, and then the corresponding 3-acylisoxaszoles were obtained by reacting with alkynes via the 1,3-dipolar [3+2] cycloaddition. These heterogeneous catalysts are easily separable from the reaction mixture and reused. This synthetic method provides a facile, efficient, and reusable production of 3-acylisoxazoles.