Synthesis of a close analog of the repeating unit of the antifreeze glycoproteins of polar fish
作者:Abul Kashem M. Anisuzzaman、Laurens Anderson、Juan L. Navia
DOI:10.1016/0008-6215(88)85096-1
日期:1988.3
Alternatively, the 1-propenyl intermediate was obtained directly by using 1-propenyl 2,4,6-tri-O-benzyl-alpha-D-galactopyranoside as the acceptor in the initial coupling reaction. An efficient 3-step synthesis of 10 was accomplished by the dibutyltin oxide-assisted, selective crotylation of allyl alpha-D-galactopyranoside at O-3, followed by benzylation and treatment of the product with potassium tert-butoxide
被保护的糖肽N-(苄氧羰基)-L-丙氨酰基-[O-(2,3,4,6-四-O-苯甲酰基-β-D-吡喃半乳糖基)-(1-3)-O-(通过偶合2,4,6-三-O-苄基-α-D-吡喃半乳糖(1 ---- 3)]-L-苏氨酰基-L-丙氨酸2,2,2-三氯乙基酯各自的二糖和三肽嵌段。通过将四-O-苯甲酰基-α-D-半乳糖吡喃糖基溴化物偶联到烯丙基2,4,6-三-O-苄基-α-D-吡喃半乳糖苷并将产物转化为O-(2,3,通过1-丙烯基糖苷的4,6-四-O-苯甲酰基-β-D-吡喃半乳糖基)-(1 ---- 3)-2,4,6-三-O-苄基-α-D-吡喃半乳糖基氯和游离的(1-OH)糖。或者,在初始偶联反应中,通过使用1-丙烯基2,4,6-三-O-苄基-α-D-吡喃半乳糖苷直接作为受体,获得1-丙烯基中间体。通过在O-3处烯丙基α-D-吡喃半乳糖苷的二丁基氧化锡辅助的选择性丁酰化,然后进行苄基化和用叔丁醇钾处