amnopyranoside (22), a building block for the alpha-D-Galp-(1----3)-alpha-D-Glcp-(1----3)-alpha-L-Rhap fragment of the capsular polysaccharides of Streptococcus pneumoniae types 6A and 6B [----2)-alpha-D-Galp-(1----3)-alpha-D-Glcp-(1----3)-alpha-L-Rhap-( 1----X)-D- RibOH-(5-P----]n (6A, X = 3; 6B, X = 4) has been synthesised. Ethyl 3-O-allyl-2,4,6-tri-O-benzyl-1-thio-beta-D-glucopyranoside was coupled
4-甲氧基苄基2,4-二-O-苄基-3-O- [2,4,6-三-O-苄基-3-O-(3,4,6-三-O-苄基-α-D -半
乳糖吡喃糖基)-α-
D-吡喃葡萄糖基]-α-
L-鼠李糖吡喃糖苷(22),α-D-Galp-(1 ---- 3)-alpha-D-Glcp-(1- --3)肺炎链球菌6A和6B型荚膜
多糖的α-L-Rhap片段[---- 2)-α-D-Galp-(1 ---- 3)-α-D-Glcp -(1 ---- 3)-alpha-L-Rhap-(1 ---- X)-D- RibOH-(5-P ----] n(6A,X = 3; 6B,X = 4)已经合成了乙基3-O-烯丙基-2,4,6-三-O-苄基-1-
硫代-β-
D-吡喃葡萄糖苷与4-甲氧基苄基2,4-二-O-苄基-以三
氟甲磺酸甲酯为
促进剂,在
乙醚中形成α-
L-鼠李糖吡喃糖苷,将所得的α-D-Glcp-(1 ---- 3)-α-L-