Regioselective N-nitrosation of dihydropyrimidinones with nitric oxide

N-Nitrosation of dihydropyrimidinones with nitric oxide occurred regioselectively, giving the corresponding N(3)-nitrosamides in high yields. The reaction most likely took place by a nucleophilic attack. Aprotic and polar solvents, such as CH3CN and tetrahydrofurane (THF) greatly favored the reaction, whereas protic solvents with high dielectric constant, such as CH3OH and water, disfavored it.