Synthesis of Glycolipid Probes for Elucidation of the Pathological Mechanism of Carbohydrate-Deficient Glycoprotein Syndrome

为阐明糖缺乏糖蛋白综合征（CDGS）的病理机制，我们研究了N-连接糖蛋白生物合成途径中的“脂质中间体”及其前体-长链糖基磷酸等糖脂探针的合成方法。主要研究结果如下：1）新型磷酸化试剂的制备与应用：我们开发了一种利用双磷酸化试剂对磷脂和糖磷酸进行高效的处理（三甲基硅基乙基）亚磷酸酯（1）作为一种新的磷酰化试剂。2）长链糖基磷酸酯的合成：作为模型反应，我们通过1与相应的脂质醇，即香茅醇和多萜醇反应，合成了香茅基磷酸酯（2）和多萜基磷酸酯（3）。另一方面，葡萄糖基氟化物用于双（三甲基甲硅烷基乙基）磷酸盐（4）的葡萄糖基化。将得到的葡糖基磷酸（5）与3进行缩合，得到长链葡糖基焦磷酸（6）。在一锅法中，多萜醇与2，3，4，6-四-O-乙酰基甘露糖在邻氯苯基磷二氯存在下反应，得到多萜醇甘露糖基磷酸（7）。3）含有β-D-吡喃甘露糖苷的寡糖的组装：通过葡糖磺酰β 1 * 4 N-乙酰葡糖胺的立体选择性还原，其通过用从葡萄糖获得的葡糖磺酰溴对GlcNAc进行β-选择性糖基化，经6步以39%的总收率制备。

Aiming at elucidation of pathological mechanism of carbohydrate-deficient glycoprotein syndrome (CDGS), we investigated the synthetic method for glycolipid probes such as "Lipid Intermediate" and its precursors, dolichyl glycosyl phosphates designated in the biosynthetic pathway for N-linked glycoproteins. The results are summarized on the following items.1) Preparation and utilization of a novel phosphorilating agent : We have developed an efficient entry to phospholipids and glycophosphates using bis (trimethylsilylethyl) phosphite (1) as a novel phosphorilating agent.2) Synthesis of dolichyl glycosyl phosphates : As a model reation we have synthesized citronellyl phosphate (2) and dolichyl phosphate (3) by the reaction of 1 with the respective lipid alcohols, namely citronellol and dolichol. On the other hand glucosyl fluoride was used for glucosylation of bis (trimethylsilylethyl) phosphate (4). The resulting glucosyl phosphate (5) was subjected to the condensation with 3, giving dolichyl glucosyl pyrophosphates (6). Reaction of dolichol with 2,3,4,6-tetra-O-acetylmammose in the presence of o-chlorophenyl phosphodichloride afforded dolichyl mannosyl phosphate (7) in one-pot process.3) Assembly of oligosaccharides containing beta-D-mannopyranoside : An efficatious route to the mannosylbeta1*4N-acetylglucosamine was developed by means of stereoselective reduction of glucosulosylbeta1*4N-acetylglucosamine, which was prepared by beta-selective glycosylation of GlcNAc with glucosulosyl bromide obtained from glucose by 6 steps in 39% overall yield.