Convergent synthesis of the methyl glycosides of a tetra- and a pentasaccharide fragment of the Shigella flexneri serotype 2a O-specific polysaccharide
作者:Fabienne Segat-Dioury、Laurence A. Mulard
DOI:10.1016/s0957-4166(02)00580-3
日期:2002.10
The branched pentasaccharide, α-l-Rhap-(1→3)-[α-d-Glcp-(1→4)]-α-l-Rhap-(1→3)-β-d-GlcNAcp-(1→2)-α-l-Rhap (B(E)CDA) and the corresponding linear tetrasaccharide (ECDA), which are part of the Shigella flexneri serotype 2a O-antigen, were synthesized as their methyl glycosides according to a convergent strategy. The syntheses rely on the use of suitable B(E)C and EC trichloroacetimidate donors, respectively
支化的五糖,α-L-鼠李糖p - (1→3) - [α-d-GLC p - (1→4)] - α-L-鼠李糖p - (1→3)-β-d-GlcNAc的p - (1→2)-α-L-鼠李糖p(B(E)CDA)和相应的线性四糖(ECDA),这是一部分的痢疾杆菌血清型2A ø -抗原,合成为根据它们的甲基糖苷趋同的策略。合成分别依赖于使用合适的B(E)C和EC三氯乙酰亚胺酸酯供体,并且涉及带有合适的DA受体,该受体带有异亚丙基乙缩醛以阻断残基D的OH-4和OH-6 。还描述了用作模型的相关线性CDA-OMe三糖的制备。