MICROWAVE-ASSISTED EFFICIENT AND CONVENIENT ONE-POT SYNTHESIS OF NOVEL 3-(4-AMINOTHIENO[2,3-<i>d</i>]PYRIMIDIN-5-YL)COUMARINS UNDER SOLVENT-FREE CONDITIONS

Abstract

An efficient green synthesis of novel 3-(4-aminothieno[2,3-d]pyrimidin-5-yl)coumarins has been developed. One-pot reaction of 3-acetylcoumarin, malononitrile, and elemental sulfur, catalyzed by L-proline, resulted in the formation of thiophene derivatives, which were used as precursors for the synthesis of 3-(4-aminothieno[2,3-d]pyrimidin-5-yl)coumarins. Target compounds were prepared by a one-pot method or stepwise, and NH4OAc was exploited as a reagent and molten salt. Microwave irradiation method was successfully applied to afford the products in excellent yields.