Synthesis of nor-C-linked neuraminic acid disaccharide: a versatile precursor of C-analogs of oligosialic acids and gangliosides.
The Neu5Acalpha(2,8)Neu5Ac disaccharide is an important constituent of tumor related antigen, however, the O-linkage is catabolically unstable. Vaccination with a catabolically stable sialic acid C-glycoside analog might enhance immunogenicity. The synthesis of Neu5Ac nor-C-disaccharide 20R/S, corresponding to versatile precursors of C-analogs of oligosialic acid and gangliosides, is reported. The synthesis of the protected acceptor was not straightforward, as ester, silyl ether, and isopropylidene protection failed to afford desired C-linked disaccharide. Allyl ether protection of hydroxyl groups and acetyl protection of the acetamido facilitated the successful synthesis of the 8-aldehyde neuraminyl acceptor. Samarium mediated C-glycosylation afforded the desired nor-C-disaccharide as a mixture of two separable diastereomers.
Yuan
Xuejun
X
Department of Chemistry and Chemical Biology, Rensselaer Polytechnic Institute, Troy, New York 12180, USA.
Ress
Dino K
DK
Linhardt
Robert J
RJ
D002236:Carbohydrate Conformation; D004187:Disaccharides / Q000138:chemical synthesis* / Q000737:chemistry; D005732:Gangliosides / Q000737:chemistry*; D006031:Glycosylation; D019158:N-Acetylneuraminic Acid / Q000737:chemistry*; D009438:Neuraminic Acids / Q000138:chemical synthesis* / Q000737:chemistry
D004187:Disaccharides; D005732:Gangliosides; D009438:Neuraminic Acids; D019158:N-Acetylneuraminic Acid