Synthesis of <i>Cryptococcus neoformans</i> Capsular Polysaccharide Structures. IV. Construction of Thioglycoside Donor Blocks and Their Subsequent Assembly
作者:Mia Alpe、Stefan Oscarson、Pär Svahnberg
DOI:10.1081/car-120026459
日期:2003.12.31
Di‐ and trisaccharide thioglycoside building blocks, ethyl (2,3,4‐tri‐O‐benzyl‐β‐d‐xylopyranosyl)‐(1→2)‐3‐O‐allyl‐4,6‐di‐O‐benzyl‐1‐thio‐α‐d‐mannopyranoside, ethyl (2,3,4‐tri‐O‐benzyl‐β‐d‐xylopyranosyl)‐(1→2)‐6‐O‐acetyl‐3‐O‐allyl‐4‐O‐benzyl‐1‐thio‐α‐d‐mannopyranoside and ethyl (2,3,4‐tri‐O‐benzyl‐β‐d‐xylopyranosyl)‐(1→4)‐[(2,3,4‐tri‐O‐benzyl‐β‐d‐xylopyranosyl)‐(1→2)]‐3‐O‐allyl‐6‐O‐benzyl‐1‐thio‐α‐d‐mannopyranoside
二糖和三糖硫代糖苷结构单元,乙基(2,3,4-三-O-苄基-β-d-吡喃吡喃糖基)-(1→2)-3-O-烯丙基-4,6-二-O-苄基-1-硫代-α-d-甘露吡喃糖苷,乙基(2,3,4-三-O-苄基-β-d-吡喃并吡喃糖基)-(1→2)-6-O-乙酰基-3-3-O-烯丙基4-O-苄基-1-硫代-α-d-吡喃吡喃糖苷和乙基(2,3,4-三-O-苄基-β-d-吡喃吡喃糖基)-(1→4)-[(2,3,4 -三-O-苄基-β-d-吡喃吡喃糖基)((1→2)]-3-O-烯丙基-6-O-苄基-1-硫代-α-d-吡喃吡喃糖苷,对应于荚膜中的重复结构新型隐球菌多糖(CPS)是利用三氟甲磺酸银促进的苯并溴木糖与适当保护的甘露糖乙基硫代糖苷之间的偶联而合成的。这些嵌段在甘露糖残基的3位含有一个正交的烯丙基,以允许CPS(1→3)连接的甘露聚糖主链的继续形成。它们具有苄基醚作为持久性保护基,以促进接近乙酰化靶标结