Catelani G, Marra A, Paquet F, Sinaÿ P
Carbohydr Res. 1986 Nov 1;155:131-40. doi: 10.1016/s0008-6215(00)90139-3.
Benzyl 2-azido-2-deoxy-beta-D-galactopyranoside was converted into benzyl 2-azido-4,6-O-benzyl-2-deoxy-beta-D-galactopyranoside via benzylidenation, p-methoxybenzylation, acid hydrolysis, benzylation, and selective oxidation. Condensation of 1,2,3,4,6-penta-O-acetyl-beta-D-galactopyranose with benzyl 2-azido-4,6-di-O-benzyl-2-deoxy-beta-D-galactopyranoside in the presence of trimethylsilyl triflate gave crystalline benzyl 2-azido-4,6-di-O-benzyl-2-deoxy-3-O-(2,3,4,6-tetra-O-acetyl-beta-D-ga lactopyranosyl)-beta-D-galactopyranoside (76%), which was converted into benzyl 2-azido-4,6-di-O-benzyl-2-deoxy-3-O-(2,6-di-O-benzyl-beta-D-galactopy ranosyl)-beta-D-galactopyranoside and condensed with 3,4,6-tri-O-acetyl-2-azido-2-deoxy-alpha-D-galactopyranosyl bromide in the presence of silver silicate on alumina and molecular sieve 4 A to give 61% of benzyl O-(3,4,6-tri-O-acetyl-2-azido-2-deoxy-beta-D-galactopyranosyl)-(1----4)- O-(2,6-di- O-benzyl-beta-D-galactopyranosyl)-(1----3)-2-azido-4,6-di-O-benzyl-2-deo xy- beta-D-galactopyranoside. Reduction with sodium borohydride followed by N-acetylation, O-deacetylation, and catalytic hydrogenolysis then gave O-(2-acetamido-2-deoxy-beta-D-galactopyranosyl)-(1----4)-O-beta-D-gal actopyranosyl-(1----3)-2-acetamido-2-deoxy-D-galactopyranose, the desialylated human Cad-antigenic determinant.
苄基 2-叠氮基-2-脱氧-β-D-吡喃半乳糖苷通过亚苄基化、对甲氧基苄基化、酸水解、苄基化和选择性氧化转化为苄基 2-叠氮基-4,6-O-苄基-2-脱氧-β-D-吡喃半乳糖苷。1,2,3,4,6-五-O-乙酰基-β-D-吡喃半乳糖与苄基 2-叠氮基-4,6-二-O-苄基-2-脱氧-β-D-吡喃半乳糖苷在三甲基甲硅烷基三氟甲磺酸酯存在下缩合，得到结晶状的苄基 2-叠氮基-4,6-二-O-苄基-2-脱氧-3-O-(2,3,4,6-四-O-乙酰基-β-D-吡喃半乳糖基)-β-D-吡喃半乳糖苷（76%），其被转化为苄基 2-叠氮基-4,6-二-O-苄基-2-脱氧-3-O-(2,6-二-O-苄基-β-D-吡喃半乳糖基)-β-D-吡喃半乳糖苷，并在氧化铝负载的硅酸银和 4A 分子筛存在下与 3,4,6-三-O-乙酰基-2-叠氮基-2-脱氧-α-D-吡喃半乳糖基溴缩合，得到 61%的苄基 O-(3,4,6-三-O-乙酰基-2-叠氮基-2-脱氧-β-D-吡喃半乳糖基)-(1→4)-O-(2,6-二-O-苄基-β-D-吡喃半乳糖基)-(1→3)-2-叠氮基-4,6-二-O-苄基-2-脱氧-β-D-吡喃半乳糖苷。随后用硼氢化钠还原，接着进行 N-乙酰化、O-脱乙酰化和催化氢解，得到 O-(2-乙酰氨基-2-脱氧-β-D-吡喃半乳糖基)-(1→4)-O-β-D-吡喃半乳糖基-(1→3)-2-乙酰氨基-2-脱氧-D-吡喃半乳糖，即去唾液酸的人 Cad 抗原决定簇。
