Yili Ding

Generation of ñ-Linked Oligosaccharide Libraries by Random Glycosylation on Unprotected Acceptors

Background: The GlcNAc related disaccharides were reported to show inhibitory activity on breast tumor cells (MDAMB- 231). However, synthesis of disaccharides is lengthy, laborious and time consuming, and it is necessary to find more efficient methods to generate the disaccharide libraries. Random glycosylation has been an established practice to generate β-linked disaccharides library. Synthesis of α-linked disaccharide libraries by random glycosylation hasn’t been explored yet. We present our results on the synthesis of α-linked GlcNAc related disaccharide libraries by random glycosylation in this article. Results: Employing random glycosylation as a key step on an unprotected GlcNAc monosaccharide, and after deprotection and careful purification, few α-linked GlcNAc related disaccharide libraries were obtained in acceptable ratios, and the results were confirmed by mass and NMR spectral data. Conclusion: Random glycosylation was demonstrated as an efficient method for the synthesis of α-linked GlcNAc related oligosaccharide libraries.

Synthesis of Sialyl Lewis X Related Tetrasaccharide Library Through Random Fucosylation on a Partially Protected Trisaccharide

Background Carbohydrate recognition has been shown to be involved in various biological processes. E-selectin is expressed on the endothelial cells stimulated by cytokines, such as IL-1β or TNF-α at inflammatory sites and plays an important role in the transport of neutrophils to inflammatory sites. The tetrasaccharide SLex is distributed on the surface of neutrophils and has been shown to be a ligand recognized by E-selectin. SLex and its derivatives can block the interaction between SLex and E-selectin and will be useful as the anti-inflammatory and anti-tumor agents. Results Random fucosylation on a partially protected sialyl LacNAc trisaccharide, resulted in the corresponding glycosylated products as a mixture. After careful purification, debenzylation, deacetylation, alkaline hydrolysis and further purification on C-18 column, a tetrasaccharide library containing five sialyl lewis X related tetrsaccharides was obtained, and the results were confirmed by proton NMR study. Conclusion Random fucosylation was demonstrated as efficient method to generate sialyl related tetrasaccharide library.