Independent synthesis of three types of N-substituted dihydropyrimidines by desulphurization and their properties

Abstract

N-Substituted pyrimidine-2(1H)-thiones (1), 3,4-(2), and 3,6-dihydropyrimidine-2(1H)-thiones (3) were easily desulphurized with Raney nickel to give N-substituted 1,2-(4), 1,4-(5), and 1,6-dihydropyrimidines (6), respectively. Further, the properties of these N-substituted dihydropyrimidine isomers, e.g. spectral characteristics, pK_a values, and stabilities are also discussed.