An Alternative Access to a Trisaccharide Repeating Unit of the Capsular Polysaccharide of Streptococcus pneumoniae Serotype 19A.
作者:Eisuke KAJI、Yumiko OSA、Mutsumi TANAIKE、Yugo HOSOKAWA、Hiroaki TAKAYANAGI、Atsushi TAKADA
DOI:10.1248/cpb.44.437
日期:——
A chemical synthesis has been achieved for beta-D-ManNAc-(1-->4)-alpha-D-Glc-(1-->3)-L-Rha, a trisaccharide repeating unit of the capsular polysaccharide of Streptococcus pneumoniae serotype 19A, by stepwise link-up of the suitably functionalized, constituent sugar units. A beta-selective glycosylation of trimethylsilylethyl glucoside having free 4-OH with 2-(benzoyloxyimino)-2-deoxyglycosyl bromide
化学合成已经实现了β-D-ManNAc-(1→4)-α-D-Glc-(1→3)-L-Rha,这是肺炎链球菌荚膜多糖的三糖重复单元。通过逐步连接适当官能化的糖单元,获得血清型19A。用2-(苯甲酰氧基亚氨基)-2-脱氧糖基溴化物将具有游离4-OH的三甲基甲硅烷基乙基葡糖苷进行β选择性糖基化,然后进行甘露聚糖选择性硼氢化,N-乙酰化和异头中心官能化(1-OSE-> 1 -OH-> 1-F),得到关键的二糖供体,β-D-ManNAc-(1-> 4)-alpha-D-Glc-(1-> F.L-鼠李糖基糖基化解封后,具有供体底物的受体受体在13步中从D-葡萄糖以6.5%的产率提供了目标三糖。