glycosides. The pentasaccharide analogues each have two formamido groups replaced by hydroxyl groups. Protected derivatives of the three oligosaccharides were prepared by in situ activation with bromine of mono- and di-saccharide thioglycosides of D-rhamnose and 4-azido-4,6-dideoxy-D-mannose in the presence of a glycosyl acceptor and silver triflate as promoter. Reduction of the azido groups with hydrogen sulfide
制备了两个五
糖类似物和布鲁氏菌A抗原[---- 2]-α-D-Rhap4NFo-(1 ----] n的六糖片段作为甲基糖苷,每个五
糖类似物具有两个甲酰胺基。三种
寡糖的保护衍
生物是通过在D-
鼠李糖和4-azido-4,6-dideoxy-
D-甘露糖存在下用D-
鼠李糖和4-azido-4,6-dideoxy-
D-甘露糖的
单糖和二糖
硫糖苷的
溴原位活化来制备的。糖基受体和
三氟甲磺酸银作为
促进剂,用
硫化氢还原
叠氮基,用
甲酸乙酯进行N-甲酰化,然后氢解,得到目标五糖苷。