Synthesis of Nor-C-linked Neuraminic Acid Disaccharide: A Versatile Precursor of C-Analogs of Oligosialic Acids and Gangliosides

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• 作者：Xuejun Yuan ; Dino K. Ress ; Robert J. Linhardt
• 刊名：Journal of Organic Chemistry
• 出版年：2007
• 出版时间：April 13, 2007
• 年：2007
• 卷：72
• 期：8
• 页码：3085 - 3088
• 全文大小：122K
• 年卷期：v.72,no.8(April 13, 2007)
• ISSN：1520-6904

文摘

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The Neu5Ac(2,8)Neu5Ac disaccharide is an importantconstituent of tumor related antigen, however, the O-linkageis catabolically unstable. Vaccination with a catabolicallystable sialic acid C-glycoside analog might enhance immunogenicity. The synthesis of Neu5Ac nor-C-disaccharide20R/S, corresponding to versatile precursors of C-analogsof oligosialic acid and gangliosides, is reported. The synthesisof the protected acceptor was not straightforward, as ester,silyl ether, and isopropylidene protection failed to afforddesired C-linked disaccharide. Allyl ether protection ofhydroxyl groups and acetyl protection of the acetamidofacilitated the successful synthesis of the 8-aldehyde neuraminyl acceptor. Samarium mediated C-glycosylation affordedthe desired nor-C-disaccharide as a mixture of two separablediastereomers.