carriers. Reported herein is a total synthesis of the repeating unit of Bacteroides fragilis zwitterionic polysaccharide A1 (PS A1). The structurally complex tetrasaccharide unit contains a rare sugar 2-acetamido-4-amino-2,4,6-trideoxy-d-galactose (AAT) and two consecutive 1,2-cis glycosidic linkages. The repeating unit was efficiently assembled by rapid synthesis of d-galactosamine and AAT building
从共生细菌中分离出的两性离子
多糖具有独特的免疫学特性,并且正在作为免疫治疗剂和疫苗载体出现。本文报道的是脆弱拟杆菌两性离子
多糖A1(PS A1)的重复单元的全合成。的结构复杂的四糖单元含有稀有糖2-乙酰
氨基-4-
氨基-2,4,6-三脱氧d半
乳糖(
AAT)和两个连续的1,2-顺式糖苷键。通过廉价的丰富的d-
甘露糖通过一锅S N快速合成d-半
乳糖胺和
AAT结构单元,有效地组装了重复单元2,4-双
三氟甲磺酸酯的置换和以高度立体选择性的方式安装所有糖苷键。总合成涉及最长的线性步骤,共17个步骤,总产率为3.47%。