A Facile Route to Pyrimidine-Based Nucleoside Olefins: Application to the Synthesis of d4T (Stavudine)

Article abstract of DOI:10.1021/jo00103a017

An efficient synthetic route to nucleoside olefins in the uridine, cytidine, and thymidine series is described which utilizes the Garegg-Samuelsson iodine/triphenylphosphine/imidazole-promoted deoxygenation of the 2',3'-hydroxyl groups as the key step.Cyclopentadiene ketal protection was employed for all the nucleoside 2',3'-hydroxyls to facilitate blocking of the 5'-hydroxyl and the pyrimidine nitrogens with the benzyl or 4-methoxybenzyl (PMB) groups.Deblocking of the cyclopentylidene group followed by olefination of the resulting diols provided protected nucleoside olefins 18-20.Starting with 5-methyluridine 4 and utilizing the 4-methoxybenzyl group for 5',N³ protection, the overall scheme provided the anti-HIV compound d4T (1) after deprotection of the PMB groups.The dibenzylhypoxanthine nucleoside diol 17 derived from inosine gave either unreacted starting material or decomposition products under several sets of conditions.