Molecules (Nov 2017)

Coumarin Derivatives Solvent-Free Synthesis under Microwave Irradiation over Heterogeneous Solid Catalysts

  • Souad Bouasla,
  • Juan Amaro-Gahete,
  • Dolores Esquivel,
  • M. Isabel López,
  • César Jiménez-Sanchidrián,
  • Mabrouk Teguiche,
  • Francisco J. Romero-Salguero

DOI
https://doi.org/10.3390/molecules22122072
Journal volume & issue
Vol. 22, no. 12
p. 2072

Abstract

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A suitable methodology of synthesis of coumarin derivatives by Pechmann reaction over heterogeneous solid acid catalysts in a free solvent media under microwave irradiation is described. Resorcinol, phenol and ethyl acetoacetate were selected as model reactants in the Pechmann condensation. The catalytic activity of several materials—Amberlyst-15, zeolite β and sulfonic acid functionalized hybrid silica—in solvent-free microwave-assisted synthesis of the corresponding coumarin derivatives has been investigated in detail. 7-Hydroxy-4-methylcoumarin and 4-methylcoumarin were obtained in 97% and 43% yields, respectively, over Amberlyst-15. This was the most active catalyst in the Pechmann reaction under studied conditions.

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