A simple convenient synthesis of L-[4-13C]glutamine.

l-[4-C-13]Glutamine was synthesized from sodium [2-C-13]acetate in 12 steps and 18% overall yield. A Wittig reaction of (R)-benzyl 4-formyl-2,2-dimethyloxazolidine-3-carboxylate and ethyl 2-(triphenylphosphoranylidene)[2-C-13]acetate prepared from d-serine and sodium [2-C-13]acetate, respectively, gave (4S)-4-(2-ethoxycarbonyl[2-C-13]vinyl)-2,2-dimethyloxazolidine-3-carboxylic acid ,-isopropylidene group, oxidation of the resulting hydroxyl group to a carboxyl group and transamidation of the ester moiety gave l-N-Cbz-[4-C-13]glutamine (Cbz=benzyloxycarbonyl). Finally, removal of the Cbz group gave l-[4-C-13]glutamine. l-[4-C-13]Glutamine can be prepared in fewer steps and higher yield by this method compared with previously reported methods.