Abstract The first, total synthesis of sialyl globopentaosyl ceramide (V3Neu5AcGb5Cer) and its positional isomer (V6Neu5AcGb5Cer) are described. α-Selective glycosylation of 2-(trimethylsilyl)ethyl O-(2,3,6-tri-O-benzyl-β-D-galactopyranosyl)-(1→4)-2,3,6-tri-O-benzyl-β-D-glucopyranoside (7) with the suitably protected galactose donor, methyl 3-O-acetyl-2-O-benzyl-4,6-O-benzylidene-l-thio-β-D-galactopyranoside
摘要首先介绍了
唾液酸球型戊二糖基神经酰胺(V3Neu5AcGb5Cer)及其位置异构体(V6Neu5AcGb5Cer)的全合成。2-(三甲基甲
硅烷基)乙基O-(2,3,6-三-O-苄基-β-D-
吡喃半
乳糖基)-(1→4)-2,3,6-三-O-苄基的α-选择性糖基化-β-
D-吡喃葡萄糖苷(7)与适当保护的半
乳糖供体,甲基3-O-乙酰基-2-O-苄基-4,6-O-亚苄基-
1-硫代-β-D-吡喃半乳糖苷得到所需的三糖通过除去O-乙酰基,将其转化为三糖受体。用甲基3-O-乙酰基-4,6-O-亚苄基-2-脱氧-2-邻苯二甲
酰亚胺基-
1-硫代-β-D-吡喃半乳糖苷对该受体进行糖基化,得到了球四糖衍
生物,该衍
生物经以下反应转化为受体12。除去
邻苯二甲酰基和O-乙酰基,然后进行N-乙酰化。