Mondal Prolay K, Liao Guochao, Mondal Mohabul A, Guo Zhongwu
Department of Chemistry, Wayne State University , 5101 Cass Avenue, Detroit, Michigan 48202, United States.
Org Lett. 2015 Mar 6;17(5):1102-5. doi: 10.1021/ol5036563. Epub 2015 Feb 12.
The structure of the capsular polysaccharide (CPS) of serotype Ia group B Streptococcus (GBS) has been characterized for years, but its repeating unit, which is a challenging pentasaccharide with a branch and a difficult α-sialic acid linkage, has not been synthesized yet. In this report, an effective synthesis was developed for the serotype Ia GBS CPS repeating unit, which had a reactive functionality linked to its main-chain reducing end to enable further elaboration, such as coupling with carrier proteins. The target molecule was accomplished by a convergent [2 + 3] glycosylation strategy employing a sialo-disaccharide as donor and a branched trisaccharide as acceptor. The strategy was designed to suit the synthesis of oligomers of the repeating unit.
B族链球菌(GBS)血清型Ia的荚膜多糖(CPS)结构已被研究多年,但其重复单元是一种具有挑战性的五糖,带有一个分支和一个难以合成的α-唾液酸连接,至今尚未合成。在本报告中,开发了一种有效的血清型Ia GBS CPS重复单元合成方法,该重复单元在其主链还原端连接有一个反应性功能基团,以便进行进一步修饰,例如与载体蛋白偶联。目标分子通过采用唾液酸二糖作为供体和分支三糖作为受体的汇聚式[2 + 3]糖基化策略合成。该策略旨在适用于重复单元低聚物的合成。