Department of Applied Bioorganic Chemistry, Gifu University, 1-1 Yanagido, Gifu-shi, Gifu 501-1193, Japan.
Chem Asian J. 2012 May;7(5):1041-51. doi: 10.1002/asia.201100928. Epub 2012 Feb 14.
The first total synthesis of the hybrid ganglioside X2, which consisted of a highly branched octasaccharide and ceramide moieties, was accomplished by using a glucosyl ceramide cassette approach. With a disaccharyl donor, the heptasaccharide could not be constructed by glycosylation of the C4 hydroxy group of galactose at the reducing end of the pentasaccharide. In contrast, through an alternative approach with two branched glycan units, a GM2-core trisaccharide, and a lacto-ganglio tetrasaccharide, the heptasaccharyl donor could be prepared and subsequently joined with a glucosyl ceramide cassette to afford the protected ganglioside, X2. Finally, global deprotection completed the synthesis, thus affording the pure ganglioside X2.
通过使用葡萄糖神经酰胺盒方法，首次完成了由高度支化的八糖和神经酰胺部分组成的杂交神经节苷脂 X2 的全合成。使用二糖供体，通过糖苷化五糖末端半乳糖的 C4 羟基，不能构建七糖。相比之下，通过使用两个支化聚糖单元、GM2 核心三糖和乳酰神经节四糖的替代方法，可以制备七糖供体，然后与葡萄糖神经酰胺盒连接，得到保护的神经节苷脂 X2。最后，通过全保护完成合成，从而得到纯神经节苷脂 X2。
