3-O-(3-O-benzyl-β-D-galactopyranosyl)-2-deoxy-β-D-glucopyranoside, which was regioselectively phosphorylated to give two isomeric 4,6-cyclic 2,2,2-trichloroethyl phosphates. The (R)-phosphate was subjected to catalytic hydrogenation/hydrogenolysis to give the fully deprotected title disaccharide fragment. Glycosylation of the (S)-phosphate diol with 2,4-di-O-benzyl-3,6-dideoxy-α-L-xylo-hexopyranosyl
所描述的片段包含一个带有环状 4,6-
磷酸酯的半
乳糖残基,并配有一个
氨基功能化的间隔区,允许进一步衍生化或直接结合到合适的载体上。核心 Gal-(13)-GlcNAc 二糖是通过 8-azido-3,6-dioxaoctyl 2-acetamido-4,6-O-benzylidene-2-deoxy-β-D-glucopyranoside 与 2,3, 4,6-四-O-
乙酰基-α-D-
吡喃半
乳糖基
溴在 Helferich 条件下。亚
苄基缩醛的还原开环,然后去乙酰化和选择性
苄基化得到 8-azido-3,6-dioxaoctyl 2-acetamido-6-O-benzyl-3-O-(3-O-benzyl-β-D-galactopyranosyl) -2-
脱氧-β-
D-吡喃葡萄糖苷,经区域选择性
磷酸化得到两个异构的 4,6-环状
2,2,2-三
氯乙基磷酸酯。(R)-
磷酸盐经过催化
氢化/
氢解得