The Biginelli dihydropyrimidone synthesis using polyphosphate ester as a mild and efficient cyclocondensation/dehydration reagent

Abstract

4-Aryldihydropyrimidine-2-(1H)-ones 4a-z were synthesized by one-pot, polyphosphate ester-mediated Biginelli three-component condensation. The yields of dihydropyrimidones obtained via this novel protocol are significantly higher than those utilizing the conventional ethanol/HCl method. The mechanism of the polyphosphate ester based method and the formation of side-products are also described.