香菇多糖核心片段六糖的合成研究

Synthesis of Core Gluco-hexasaccharide of Lentinan

以已知的2,3,4,6-四-O-苯甲酰基-β-D-葡萄吡喃糖-(1→3)-[2,3,4,6-四-O-苯甲酰基-β-D-葡萄吡喃糖-(1→6)]-2,4-二-O-乙酰基-β-D-葡萄吡喃糖-(1→3)-2,4,6-三-O-乙酰基-α-D-葡萄吡喃糖三氯乙酰亚胺酯(2)为供体,以2-O-苯甲酰基-4,6-O-苄叉基-α-D-葡萄吡喃糖烯丙基苷(4)作为受体,立体专一性地偶联得到β-1,3连接的五糖5.五糖5酸解脱去4,6-苯亚甲基基后与2,3,4,6-四-O-苯甲酰基-α-D-葡萄吡喃糖三氯乙酰亚胺酯(7)偶联,区域和立体专一性地得到全保护的β-1,3主链β-1,6支链的六糖8.六糖8脱保护后得到目标化合物香菇多糖核心片段六糖9.发展了合成该类化合物的一种新方法.

The known 2,3,4,6-tetra-O-benzoyl-β-D-glucopyranosyl-（1→3）-[2,3,4,6-tetra-O-benzoyl-β-D-glucopyranosyl-（1→6）]-2,4-di-O-acetyl-β-D-glucopyranosyl-（ 1→3 ）- 2,4,6,tri-O-acetyl-α-D-glucopyranosyl- trichloroacetimidate （2） was chosen as glycosyl donor to couple with allyl 4,6-O-benzylidene-2-O-benzoyl-α-D-glucopyran-oside （4） to afford β-（1→3） linked pentasaccharide 5 in a stereo-specific manner. After removal of 4,6-O-benzylidene of 5, followed by coupling with 2,3,4,6-tetra-O-benzoyl-α-D-glucopyranosyl trichloroacetimidate （7）, the blocked gluco-hexasaccharide （8） was regio- and stereo-specifically obtained. Deprotection of 8 provided the target sugar 9. Thus, a new method for the preparation of this kind of compounds was developed.