Chemistry of Heterocyclic Compounds, Vol. 41, No. 4, 2005 ... VV Lipson1, SM Desenko2, MG Shirobokova1, VV Borodina1, and VI Musatov2 ... The hydrolysis, oxidation, reduction, alkylation, formylation, and nitrosation reactions of 2-methyl-5,7- diphenyl-6,7-dihydropyrazolo [1,5-a]pyrimidine have been studied. ... Keywords: dihydropyrimidine system, acylation, alkylation, hydrolysis, reduction, nitrosation, oxidation. ... The dihydropyrimidine system ...