Chemical Synthesis of the Repeating Unit of Type II Group B <i>Streptococcus</i> Capsular Polysaccharide
作者:Liming Shao、Han Zhang、Yaoyao Li、Guofeng Gu、Feng Cai、Zhongwu Guo、Jian Gao
DOI:10.1021/acs.joc.8b00396
日期:2018.6.1
regioselective elaboration. This work also revealed that the α-Neu5Ac-(2→3)-β-d-Gal-(1→4)-β-d-GlcNAc motif, which is common in natural glycans, had a low reactivity as glycosyl donors, so it was rather difficult to directly couple this trisaccharide with sterically hindered acceptors. The motif was efficiently constructed via on-site glycan elongation using properly protected GlcN and α-Neu5Ac-(2→3)-β-d-Gal as consecutive
血清型II组B的重复单元的第一个化学合成链球菌荚膜多糖,支链七糖α-neu的p 5Ac-(2→3)-β- d -Gal p - (1→4)-β- d -GlcN p Ac-(1→3)-[β- d -Gal p-(1→6)]-β- d- Gal p }-(1→4)-β- d- Glc p-(1→3 )-β- d -Glc p-(1→,通过探索不同的合成策略并克服了一系列困难后,通过收敛的[4 + 2 + 1]糖基化反应而实现。标题化合物经设计可在其下游端带有一个游离氨基,从而能够进行进一步的区域选择性修饰这项工作还揭示了天然聚糖中常见的α-Neu5Ac-(2→3)-β- d- Gal-(1→4)-β- d- GlcNAc基序作为糖基供体的反应性较低。因此,将这种三糖与位阻受体直接偶联是相当困难的,通过使用适当保护的GlcN和α-Neu5Ac-(2→3)-β- d- Gal作为连续的糖基,通过现场聚糖延伸有效地构建了基序捐助者。