Selective deuteration of 4-N-methylcytosines

A convenient photochemical method of preparation of mono-, di- and trideuterate 4-N-methylcytosines of high isotopic purity is described. These products were obtained by photo-decarboxylation of pyrimidinyl glycines or their alpha, alpha-dideuterated derivatives in water or in deuterium oxide. [2, 2H2]Glycine derivatives were prepared by hydrogen-deuterium exchange in alkaline solution.