A one-step synthesis of 5,7-Diaryl-1,5-dihydro (or 1,2,3,5-tetrahydro)-pyrano[2,3-d]pyrimidin-2,4-diones (or 2-thioxo-4-ones)

Abstract

A one-step synthesis of 5,7-diaryl-1,5-dihydro-pyrano[2,3-d]pyrimidin-2,4-diones, 3a-c and 5,7-diaryl-2-thioxo-1,2,3,5-tetrahydropyrano[2,3-d]pyrimidin-4-ones, 3d-g was achieved by the cyclocondensation of barbituric acid or thiobarbituric acid (1) with arylideneacetophenones, 2a-d in glacial acetic acid in presence of phosphorous pentoxide. The structures of the compounds 3a-g were determined by their UV, IR, 1H NMR, 13C NMR, mass spectral data and elemental analyses.