Synthesis of the Dideoxynucleosides ddC and CNT from Glutamic Acid, Ribonolactone, and Pyrimidine Bases

Article abstract of DOI:10.1021/jo00255a021

2,3-Dideoxyribose in suitably protected form was prepared from glutamic acid and coupled with silylated cytosine to give a mixture of the α-and β-anomers of 2',3'-dideoxycitidine.The anomer ratio depended on the Lewis acid used in the coupling, with EtAlCl2 favoring the β-anomer ddC, a potent anti-HIV drug.Conjugate addition of cyanide to a 4-<(silyloxy)methyl>butenolide prepared from D-ribonolactone gave a mixture of (racemic) α- and β-3-cyanobutyrolactones.Both isomers were reduced to lactols and coupled with thymine to give α/β-anomer pairs.The α-cyano lactone, the struct ure of which was established by X-ray crystallography, afforded an authentic sample of the putative (but in fact inactive) anti-HIV substance known in AIDS research as CNT.