glucopyranosyl-beta-D-galactopyranoside 3-(sn-glycer-3-yl sodium phosphate) (4), which are trisaccharide methyl glycosides related to fragments of the capsular polysaccharide of Streptococcus pneumoniae type 18C ([----4)-beta-D- Glcp-(1----4)-[alpha-D-Glcp-(1----2)]-[Glycerol-(1-P----3)]-beta-D-Galp - (1----4)-alpha-D-Glcp-(1----3)-alpha-L-Rhap-(1----]n). Ethyl 4-O-acetyl-2,3,6-tri-O-benzyl-1-thio-be
4-二-O-苄基-α-L-鼠李
吡喃糖苷(6)。产物脱乙酰基,然后与2,4,6-三-O-乙酰基-3-O-烯丙基-α-D-
吡喃并
吡喃糖基三
氯乙
酰亚胺酸酯(18)缩合,得到苄基2,4-二-O-苄基-3 -O- [2,3,6-三-O-苄基-4-O-(2,4,6-三-O-乙酰基-3-O-烯丙基-β-D-
吡喃半
乳糖基)-α-
D-吡喃葡萄糖基]-α-
L-鼠李糖吡喃糖苷(19)。乙酰化19,然后进行甲基化,去甲酰化(---- 22),然后进一步脱保护,得到1.甲基2,4-二-O-苄基-3-O- [2,3,6-tri-O的缩合-苄基-4-O-(2,4,6-三-O-乙酰基-β-D-
吡喃半
乳糖基)-α-D-
吡喃
吡喃糖基]-α-
L-鼠李糖吡喃糖苷(22)与1,2-二-O -苄基-sn-
甘油3-(
三乙基膦酸
铵)(24),然后氧化和脱保护,得到2。2,3,4,6-四-O-苄基-1-
硫代-β-乙基的缩合
D-吡喃葡萄糖苷