title: Synthesis of the biological repeating unit of Streptococcus pneumoniae serotype 23F capsular polysaccharide.
abstract: An efficient synthesis of the 3-aminopropyl glycoside of the biological repeating unit of Streptococcus pneumoniae serotype 23F capsular polysaccharide (CPS) was accomplished. The synthetic target contained a tetrasaccharide with a phosphoglycerol branch. Its oligosaccharide backbone was assembled via linear glycosylation, and the challenging β-rhamnosyl linkage in its structure was achieved stereospecifically through naphthylmethyl-assisted intramolecular aglycon delivery (IAD). The remaining 1,2-trans glycosylation reactions were executed in excellent yields and stereoselectivity based on neighboring group participation. The phosphoglycerol branch was installed by the phosphoramidite method with benzylidene-protected glycerol 2-phosphoramidite as the substrate. Eventually, the target molecule was synthesized from monosaccharide building blocks in 17 longest linear steps and a 3.85% overall yield. In addition, the synthetic target also contained a free amino group at its reducing end, facilitating its conjugation with other molecules for various biological studies and applications.
authors.affiliation: National Glycoengineering Research Centre and Shandong Provincial Key Laboratory of Carbohydrate Chemistry and Glycobiology, Shandong University, Jinan 250100, China. guofenggu@sdu.edu.cn.
authors.forename: Kang
authors.initials: K
authors.lastname: Yu
authors.forename: Yin
authors.initials: Y
authors.lastname: Qiao
authors.forename: Guofeng
authors.initials: G
authors.lastname: Gu
authors.forename: Jian
authors.initials: J
authors.lastname: Gao
authors.forename: Shuihong
authors.initials: S
authors.lastname: Cai
authors.forename: Zhongzhu
authors.initials: Z
authors.lastname: Long
authors.forename: Zhongwu
authors.initials: Z
authors.lastname: Guo
mesh_terms: D015394:Molecular Structure; D011135:Polysaccharides, Bacterial / Q000138:chemical synthesis* / Q000737:chemistry; D065288:Serogroup; D013296:Streptococcus pneumoniae / Q000737:chemistry*
chemical_list: D011135:Polysaccharides, Bacterial