Abstract Derivatives of lactose, unsubstituted at OH-3′ and OH-4′, were glycosylated regioselectively depending on the catalyst. In a heterogeneous system with silver silicate as catalyst, glycosylation at OH-4′ was favored, whereas in a homogeneous system with silver triflate as catalyst, a favored glycosylation at OH-3′ was observed. Thus, the tetrasaccharides, O -β- D -galactopyranosyl-(1→4)- O
摘要依赖于催化剂,在OH-3'和OH-4'处未取代的
乳糖衍
生物被区域选择性地糖基化。在以
硅酸银为催化剂的非均相体系中,在OH-4'处的糖基化是有利的,而在以
三氟甲磺酸银为催化剂的均相系统中,在OH-3'处观察到了良好的糖基化。因此,四糖,O-β-D-
吡喃半
乳糖基-(1→4)-O-(2-乙酰
氨基-2-脱氧-β-D-
吡喃
吡喃糖基)-(1→4)-O-β-D-
吡喃半
乳糖基-(1→4)-
D-吡喃葡萄糖和O-β-D-
吡喃半
乳糖基-(1→4)-O-(2-乙酰
氨基-2-脱氧-β-D-
吡喃
吡喃糖基)-(1→3)-O -β-D-
吡喃半
乳糖基-(1→4)-
D-吡喃葡萄糖和三糖O-(2-乙酰
氨基-2-脱氧-β-D-
吡喃半
乳糖基)-(1→4)-O-β-D容易合成-半
乳糖吡喃糖基-(1→4)-2-乙酰
氨基-2-脱氧-
D-吡喃葡萄糖。