SYNTHESIS OF C-GLYCOSIDES OF N-ACETYLNEURAMINIC ACID AND OTHER DERIVATIVES

Reaction of the beta-pyranosyl chloride 1 of N-acetylneuraminic acid with allyl(tributyl)stannane under radical-induced conditions affords a mixture of the allyl C-glycosides 2/3. After deprotection, the pure allyl alpha-C-glycoside 5 and the analogous beta-isomer 7 can be isolated. The allyl C-glycosides 2 and 3 are converted into the corresponding epoxypropyl C-glycosides 9 and 11 by epoxidation of the allylic group. Further modified allyl C-glycosides are prepared from the C-3-hydroxylated N-acetylneuraminic acid, which are available as pure alpha- and beta-C-glycosides 19 and 21 after deprotection. At C-3 modified compounds are also synthesized which have allyl and azido residues at C-3. All compounds are interesting as potential inhibitors of sialidases, CMP sialate syntheses, and viral infection.