Two efficient synthesea of the anti-AIDS drug 2 ', 3'-dideoxycytidine (3) from N '- acetylcytidine (4) are described. In one, silylation of the C-5'hydroxyl group of 4 with tert- butyldimethylsilyl chloride followed by treatment with 1', 1'-(thiocarbony1) diimidazole gave the cyclic thionocarbonate 7, which on reaction with l, &dimethyld-phenyl-l, 3- diazaphospholidine gave the crystalline alkene 8. Hydrogenation of 8, followed by ...
