Zuurmond H M, Veeneman G H, van der Marel G A, van Boom J H
Gorlaeus Laboratories, Department of Chemistry, Leiden University, Netherlands.
Carbohydr Res. 1993 Mar 17;241:153-64. doi: 10.1016/0008-6215(93)80102-k.
Condensation of ethyl 2,4-di-O-benzoyl-1-thio-alpha-L-rhamnopyranoside with ethyl 3-O-benzyl-4-O-chloroacetyl-2-O-methyl-1-thio-beta-L-fucopyranoside in the presence of iodonium di-sym-collidine perchlorate afforded exclusively ethyl 2,4-di-O-benzoyl-3-O-(3-O-benzyl-4-O- chloroacetyl-2-O-methyl-alpha-L-fucopyranosyl)-1-thio-alpha-L-rhamnop yra noside. This disaccharide derivative was extended at C-1 with 3-benzyloxycarbonylaminopropyl 6-deoxy-3,4-O-isopropylidene-alpha-L- talopyranoside, using N-iodosuccinimide and triflic acid as the catalyst, to furnish 3-benzyloxycarbonylaminopropyl 6-deoxy-2-O-[2,4-di-O-benzoyl-3-O-(3-O-benzyl-4-O-chloroacetyl-2-O-me thy l- alpha-L-fucopyranosyl)-alpha-L-rhamnopyranosyl]-3,4-O-isopropylidene-alp ha-L- talopyranoside (20). Selective removal of the chloroacetyl group from 20, followed by condensation with ethyl 2,3-di-O-benzoyl-4-O-methyl-1-thio-alpha-L- rhamnopyranoside in the presence of the same thiophilic promoter, yielded a fully protected tetrasaccharide derivative. Deprotection of the latter gave the target compound 3-aminopropyl 6-deoxy-2-O-[3-O-[2-O- methyl-(4-O-methyl-alpha-L-rhamnopyranosyl)-alpha-L-fucopyranosyl]-alpha -L- rhamnopyranosyl]-alpha-L-talopyranoside (1).
在高氯酸二对称 - 可力丁碘鎓存在下，将2,4 - 二 - O - 苯甲酰基 - 1 - 硫代 - α - L - 鼠李吡喃糖苷乙酯与3 - O - 苄基 - 4 - O - 氯乙酰基 - 2 - O - 甲基 - 1 - 硫代 - β - L - 岩藻吡喃糖苷乙酯缩合，仅得到2,4 - 二 - O - 苯甲酰基 - 3 - O -（3 - O - 苄基 - 4 - O - 氯乙酰基 - 2 - O - 甲基 - α - L - 岩藻吡喃糖基）-1 - 硫代 - α - L - 鼠李吡喃糖苷乙酯。使用N - 碘代琥珀酰亚胺和三氟甲磺酸作为催化剂，该二糖衍生物在C - 1位与3 - 苄氧羰基氨基丙基6 - 脱氧 - 3,4 - O - 异亚丙基 - α - L - 塔罗吡喃糖苷进行扩链反应，得到3 - 苄氧羰基氨基丙基6 - 脱氧 - 2 - O - [2,4 - 二 - O - 苯甲酰基 - 3 - O -（3 - O - 苄基 - 4 - O - 氯乙酰基 - 2 - O - 甲基 - α - L - 岩藻吡喃糖基）- α - L - 鼠李吡喃糖基] - 3,4 - O - 异亚丙基 - α - L - 塔罗吡喃糖苷（20）。从20中选择性除去氯乙酰基，然后在相同的亲硫促进剂存在下与2,3 - 二 - O - 苯甲酰基 - 4 - O - 甲基 - 1 - 硫代 - α - L - 鼠李吡喃糖苷乙酯缩合，得到一个完全保护的四糖衍生物。对后者进行脱保护得到目标化合物3 - 氨基丙基6 - 脱氧 - 2 - O - [3 - O - [2 - O - 甲基 -（4 - O - 甲基 - α - L - 鼠李吡喃糖基）- α - L - 岩藻吡喃糖基] - α - L - 鼠李吡喃糖基] - α - L - 塔罗吡喃糖苷（1）。
