Kerékgyártó J, Szurmai Z, Lipták A
Institute of Biochemistry, L. Kossuth University, Debrecen, Hungary.
Carbohydr Res. 1993 Jul 5;245(1):65-80. doi: 10.1016/0008-6215(93)80060-r.
The synthesis of the title tetrasaccharide glycoside 38 is reported. p-Nitrophenyl endo-3,4-O-benzylidene-6-deoxy-alpha-L-talopyranoside (4), 3-O-acetyl-2,4-di-O-benzyl-alpha-L-rhamnopyranosyl trichloroacetimidate (7), methyl 3-O-acetyl-4-O-benzyl-2-O-methyl-1-thio-beta-L-fucopyranoside (15), 3-O-acetyl-4-O-benzyl-2-O-methyl-alpha-L-fucopyranosyl bromide (16), and ethyl 3-O-acetyl-4-O-benzyl-2-O-methyl-1-thio-alpha-D-rhamnopyranoside (33) were prepared as intermediates. Compound 4 was glycosylated with imidate 7 as well as with methyl 3-O-acetyl-2,4-di-O-benzyl-1-thio-alpha-L-rhamnopyranoside (9), affording the same disaccharide derivative 8. Deacetylation of 8 gave crystalline 17. Condensation of 17 with both fucosyl donors 15 and 16 yielded the same trisaccharide derivative 18 stereoselectively. Compound 18 was also prepared by the coupling of 4 with disaccharide glycosyl donor 20. After deacetylation of 18 (-->34), methyl triflate-promoted glycosylation with compound 33 resulted in tetrasaccharide 35. Conversion of the p-nitrophenyl group of 35 into the p-trifluoroacetamidophenyl group (-->36) and removal of the protecting groups gave the title tetrasaccharide glycoside 38.
报道了标题四糖糖苷38的合成。对硝基苯基内型-3,4-O-亚苄基-6-脱氧-α-L-塔罗吡喃糖苷（4）、3-O-乙酰基-2,4-二-O-苄基-α-L-鼠李吡喃糖基三氯乙酰亚胺酯（7）、3-O-乙酰基-4-O-苄基-2-O-甲基-1-硫代-β-L-岩藻吡喃糖苷（15）、3-O-乙酰基-4-O-苄基-2-O-甲基-α-L-岩藻吡喃糖基溴化物（16）和3-O-乙酰基-4-O-苄基-2-O-甲基-1-硫代-α-D-鼠李吡喃糖苷乙酯（33）被制备为中间体。化合物4与亚胺酯7以及3-O-乙酰基-2,4-二-O-苄基-1-硫代-α-L-鼠李吡喃糖苷（9）进行糖基化反应，得到相同的二糖衍生物8。8的脱乙酰化得到结晶的17。17与岩藻糖基供体15和16缩合，立体选择性地得到相同的三糖衍生物18。化合物18也通过4与二糖糖基供体20偶联制备。18脱乙酰化（→34）后，用化合物33进行甲基三氟甲磺酸酯促进的糖基化反应，得到四糖35。将35的对硝基苯基转化为对三氟乙酰胺基苯基（→36）并除去保护基，得到标题四糖糖苷38。
