A Facile Route to Pyrimidine-Based Nucleoside Olefins: Application to the Synthesis of d4T (Stavudine)
作者:Frederick A. Luzzio、Michael E. Menes
DOI:10.1021/jo00103a017
日期:1994.12
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. Cyclopentylidene 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',N-3 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.