Kihlberg J, Frejd T, Jansson K, Kitzing S, Magnusson G
Chemical Center, Lund Institute of Technology, Sweden.
Carbohydr Res. 1989 Feb 1;185(2):171-90. doi: 10.1016/0008-6215(89)80033-3.
The glycosyl chlorides of the 3-O-methyl (6) and 4-deoxy-4-fluoro (8) O-benzylated derivatives of D-galactopyranose and 2,3,4,6-tetra-O-benzyl-D-glucopyranose were condensed with methyl 2,3,6-tri-O-benzoyl-beta-D-galactopyranoside to give, after deprotection, the 3'-O-methyl (23), 4'-deoxy-4'-fluoro (25), and 4'-epi (27) derivatives, respectively, of methyl beta-D-galabioside (1). The glycosyl fluorides of 2,3,4-tri-O-benzyl-D-fucopyranose and the 3-deoxy (12) and 4-deoxy (16) O-benzylated derivatives of D-galactopyranose were condensed with methyl 2,3,6-tri-O-benzyl-beta-D-galactopyranoside (21), to give, after deprotection, the 6'-deoxy (31), 3'-deoxy (34), and 4'-deoxy (37) derivatives of 1, respectively. The 2'-deoxy (41) derivative of 1 was prepared by N-iodosuccinimide-induced condensation of 3,4,6-tri-O-acetyl-D-galactal and 21 followed by deprotection. Treatment of methyl 2,3,6-tri-O-benzoyl-4-O-(2,3-di-O-benzoyl-alpha-D-galactopyranosyl)-beta -D- galactopyranoside with Et2NSF3 (DAST), followed by deprotection, provided the 6'-deoxy-6'-fluoro (46) derivative of 1. Molecular mechanics calculations yielded conformations for 23, 25, 27, 31, 34, 37, 41, and 46 with small deviations from the calculated conformation for 1 (phi H/psi H: -40 degrees/-6 degrees).
将D-吡喃半乳糖和2,3,4,6-四-O-苄基-D-吡喃葡萄糖的3-O-甲基（6）和4-脱氧-4-氟（8）O-苄基化衍生物的糖基氯与甲基-2,3,6-三-O-苯甲酰基-β-D-吡喃半乳糖苷缩合，脱保护后分别得到β-D-半乳糖二糖苷（1）的3'-O-甲基（23）、4'-脱氧-4'-氟（25）和4'-表位（27）衍生物。将2,3,4-三-O-苄基-D-岩藻糖的糖基氟化物以及D-吡喃半乳糖的3-脱氧（12）和4-脱氧（16）O-苄基化衍生物与甲基-2,3,6-三-O-苄基-β-D-吡喃半乳糖苷（21）缩合，脱保护后分别得到1的6'-脱氧（31）、3'-脱氧（34）和4'-脱氧（37）衍生物。1的2'-脱氧（41）衍生物是通过N-碘代琥珀酰亚胺诱导3,4,6-三-O-乙酰基-D-半乳糖烯与21缩合然后脱保护制备的。用Et2NSF3（DAST）处理甲基-2,3,6-三-O-苯甲酰基-4-O-（2,3-二-O-苯甲酰基-α-D-吡喃半乳糖基）-β-D-吡喃半乳糖苷，然后脱保护，得到1的6'-脱氧-6'-氟（46）衍生物。分子力学计算得出23、25、27、31、34、37、41和46的构象，与1的计算构象（φH/ψH：-40°/-6°）偏差较小。
