Syntheses of β-(1→6)-branched β-(1→3)-linked d-galactans that exist in the rhizomes of Atractylodes lancea DC
作者:Aixiao Li、Fanzuo Kong
DOI:10.1016/j.carres.2005.05.017
日期:2005.9
β-(1→6)-linked disaccharide donor 4 . Condensation of 2 with 5 and subsequent selective deacetylation by methanolysis produced the β-(1→6)-linked disaccharide acceptor 7 . Reaction of 7 with 4 , oxidative cleavage of 1-OMP, and trichloroacetimidate formation produced the tetrasaccharide donor 9 . The penta- ( 15 ), the hexa- ( 17 ), and the heptasaccharide donor 19 were synthesized similarly. Meanwhile
摘要用2,3,4,6-四-O-苯甲酰基-α-d-吡喃半乳糖基三氯乙酰亚氨酸酯(1 ),4-甲氧基苯基2,3,4-三-O-苯甲酰基-β-d-吡喃半乳糖苷(2),6-O-乙酰基-2,3,4-三-O-苯甲酰基-α-d-吡喃半乳糖基三氯乙酰亚氨酸(5),4-甲氧基苯基6-O-乙酰基-2,4-二-O-苯甲酰基-β-d-吡喃半乳糖苷(22)和4-甲氧基苯基2,4,6-三-O-苯甲酰基-β- d-半乳糖吡喃糖苷(26)为关键合成子。将2与1偶联,然后将1-OMP氧化裂解,随后形成三氯乙酰亚氨酸酯,得到β-(1→6)连接的二糖供体4。2与5的缩合以及随后的甲醇解选择性脱乙酰基产生了β-(1→6)连接的二糖受体7。7与4的反应,1-OMP的氧化裂解和三氯乙亚氨酸盐的生成产生了四糖供体9。相似地合成五(15),六(17)和七糖供体19。同时,用22处理1产生β-(1→3)-连接的二糖23和α-(1→3)-连接