Abstract The title branched-trisaccharide derivatives ( 9 and 13 ) have been synthesised from methyl 2,3- O -(2-nitrobenzylidene)-α- l -rhamnopyranoside ( 2 ) using the 2-nitrobenzylidene residue as a temporary blocking-group. Condensation of 2 with methyl (2,3,4-tri- O -acetyl-α- d -glucopyranosyl bromide)uronate afforded the blocked disaccharide 3 which, on sequential photolysis and oxidation, gave
摘要以2-硝基亚苄基残基为临时封端基,由甲基2,3-O-(2-硝基苄叉)-α-1-R-鼠李
吡喃糖苷(2)合成了标题分支的三糖衍
生物(9和13)。2与(2,3,4-三-O-乙酰基-α-d-
吡喃
葡萄糖基
溴化甲基)
尿酸甲酯缩合得到封闭的二糖3,该二糖3在顺序光解和氧化后得到4-O-(甲基2,3甲基,4-三-O-乙酰基-β-d-
吡喃
葡萄糖基
尿酸酯)-2-O-(2-
硝基苯甲酰基)-(4)和-3-O-(2-
硝基苯甲酰基)-α-1-
鼠李糖吡喃糖苷(5) 4:1的混合物。HO-3的半
乳糖基化反应得到两个具有βαα和ββα构型的完全保护的三糖,在脱酰基,皂化和用离子交换
树脂处理后,得到了
游离酸9和13。