Reaction of 1,4-Benzoquinone with 2-(2-Oxo-2-arylethylidene)-2,3-dihydropyrimidine-4(1H)-ones

Reactions of 1,4-benzoquinone with 2-(2-oxo-2-arylethylidene)-2,3-dihydro-1H-pyrimidine-4-ones in glacial acetic acid proceed selectively to give 2-[1-(2,5-dihydrophenyl)-2-oxo-2-arylethylidene]-2,3-dihydropyrimidine-4(1H)-ones.