5-?Methyl-2,?4(1H,?3H)?-?pyrimidinedione-?2-?13C-?1,?3-?15N2 is an intermediate in synthesizing 5-Methyl-2’-deoxy Cytidine-13C,15N2 (M295904). It is an isotopic analog of 5-Methyl-2’-deoxy Cytidine (M295900), a Cytidine (C998300) analog and also an isostere of Thymidine (T412000).