Chowdhary M S, Navia J L, Anderson L
Carbohydr Res. 1986 Aug 1;150:173-85. doi: 10.1016/0008-6215(86)80014-3.
Several 2-O-benzoyl-4,6-di-O-benzyl-3-O-R-alpha-D-galactopyranosyl chlorides, designed as general precursors of beta-linked, interior D-galactopyranosyl residues in oligosaccharides, were tested in a sequential synthesis of the galactotriose beta-D-Galp-(1----3)-beta-D-Galp-(1----3)-D-Gal (19). The chlorides having R = tetrahydro-2-pyranyl and tert-butyldimethylsilyl gave excellent results, whereas those having R = 3-benzoylpropionyl and chloroacetyl were unsatisfactory. An activated disaccharide block (17), having R = 2,3-di-O-benzoyl-4,6-di-O-benzyl-beta-D-galactopyranosyl, was also prepared and tested as a glycosyl donor. The coupling of 17 to 1-propenyl 2-O-benzoyl-4,6-di-O-benzyl-alpha-D-galactopyranoside (14), in the molar ratio 1.13:1, gave 64% of a trisaccharide derivative (18) that could be converted into 19. This latter synthesis of 19 is efficient because all three galactose units are derived from 14 or its immediate precursor.
设计为寡糖中β-连接的内部D-吡喃半乳糖残基通用前体的几种2-O-苯甲酰基-4,6-二-O-苄基-3-O-R-α-D-吡喃半乳糖酰氯，在半乳糖三糖β-D-Galp-(1→3)-β-D-Galp-(1→3)-D-Gal (19)的连续合成中进行了测试。R为四氢-2-吡喃基和叔丁基二甲基甲硅烷基的氯化物给出了优异的结果，而R为3-苯甲酰基丙酰基和氯乙酰基的那些则不令人满意。还制备了具有R = 2,3-二-O-苯甲酰基-4,6-二-O-苄基-β-D-吡喃半乳糖基的活化二糖砌块(17)，并作为糖基供体进行了测试。17与1-丙烯基2-O-苯甲酰基-4,6-二-O-苄基-α-D-吡喃半乳糖苷(14)以1.13:1的摩尔比偶联，得到64%的三糖衍生物(18)，其可以转化为19。19的后一种合成是有效的，因为所有三个半乳糖单元均衍生自14或其直接前体。
