Regioselectivity in the amination of methylsulfanyl-substituted azines with O-mesitylenesulfonylhydroxylamine

Reactions of O-mesitylenesulfonylhydroxylamine with 2-(methylsulfanyl)pyrazine, 2-(methylsulfanyl) pyrimidine, and 3,5-dimethyl-2-(methylsulfanyl)pyrimidines involve both sulfur and nitrogen atoms. The amination products at the sulfur atom prevail in the resulting mixture of isomeric cations, and the ratio of the S-NH₂ and N-NH₂ derivatives depends on the substrate nature. The experimental data were interpreted in terms of DFT quantum-chemical calculations.