Synthesis of a spacer-containing nonasaccharide fragment of Streptococcus pneumoniae 19F capsular polysaccharide
作者:Magnus Nilsson、Thomas Norberg
DOI:10.1039/a709293h
日期:——
The nonasaccharide 1, representing three repeating units of the capsular polysaccharide from Streptococcus pneumoniae 19F, has been synthesized. The synthetic strategy is to first synthesize, by an AB + C route, trisaccharide derivative 14, having O-benzyl groups as persistent, and 1-O-allyl and 4″-O-acetyl groups as temporary, protecting groups. Then, specific replacement of the 1-O-allyl group with an α-H-phosphonate monoester gives trisaccharide 17, which is coupled to a spacer. The obtained derivative 18 is then extended from the 4″ end in a stepwise fashion to give compound 20, using trisaccharide 17 and solution-phase H-phosphonate chemistry. Finally, removal of the persistent O-protecting groups gives the nonasaccharide 1.
合成了非五糖1,该化合物代表了源自肺炎链球菌19F的胶囊多糖的三个重复单元。合成策略是首先通过AB + C路线合成三糖衍生物14,该衍生物具有O-苄基基团作为持久保护基,同时具有1-O-烯丙基和4″-O-乙酰基作为临时保护基。然后,通过将1-O-烯丙基基团特定替换为α-H-磷酸单酯,得到三糖17,该化合物与一个间隔基团偶联。得到的衍生物18随后从4″端以逐步方式扩展,得到化合物20,使用三糖17和溶液相H-磷酸化学。最后,去除持久的O-保护基团,得到非五糖1。