Microwave-Assisted Synthesis of Coumarins via Pechmann Condensation in Wet Phosphoric Acid Imidazolium Dihydrogenphosphate

Abstract

Phosphoric acid imidazolium dihydrogenphosphate was found to work well as a catalyst and excellent reaction medium in the Pechmann condensation of substituted phenols or α-naphthol with ethyl acetoacetate to give 4-methyl coumarins under microwave irradiation. This method is simple, cost effective, requires short reaction times, and gives very good to excellent yields.

Keywords:

• Coumarin
• microwave-assisted
• Pechmann reaction
• phosphoric acid imidazolium dihydrogenphosphate

The office of the Research Vice Chancellor of Azerbaijan University of Tarbiat-Moallem is gratefully acknowledged.

Notes

^aIsolated yield after recrystallization.

^aIsolated yield after recrystallization.