Department of Science Education-Chemistry Major, Daegu University, Gyeongbuk 712-714, South Korea.
Bioorg Med Chem Lett. 2009 Dec 1;19(23):6679-81. doi: 10.1016/j.bmcl.2009.10.002. Epub 2009 Oct 4.
We have developed a new procedure based on the random glycosyl reaction of a partially benzoylated glycosyl acceptor with a glycosyl donor containing a 4,6-O-(4-methoxycarbonylbenzylidene) protecting group as a masked/caged ion-tag. Glycosylated products are ionically tagged by saponification of the methyl ester and the use of this anion-tag greatly simplifies the separation of the desired oligosaccharides from unreacted or excess glycosyl acceptors as well as from over-glycosylated oligosaccharides. In addition, the use of partially benzoylated acceptors greatly improves their solubility in dichloromethane increasing the yield of product formation and, also, of altering the distribution of positional isomers in favor of products derived by reaction of the donors at hydroxyl groups which otherwise would be considerably less reactive. Using this new approach in random glycosyl reactions, several oligosaccharide libraries were readily prepared in overall yields of 60-70% and the individual positional isomers present in the libraries were identified using the 'reductive-cleavage' method.
我们开发了一种新方法，基于部分苯甲酰化糖受体与含有 4,6-O-(4-甲氧羰基苯亚甲基)保护基的糖供体的随机糖基反应，该保护基作为掩蔽/笼状离子标记。糖基化产物通过甲酯的皂化进行离子标记，这种阴离子标记极大地简化了所需寡糖与未反应或过量糖受体以及过度糖基化寡糖的分离。此外，部分苯甲酰化受体的使用极大地提高了它们在二氯甲烷中的溶解度，增加了产物形成的产率，并且改变了位置异构体的分布，有利于由供体在羟基处反应生成的产物，否则这些产物的反应性会低得多。在随机糖基反应中使用这种新方法，我们可以轻松制备总体产率为 60-70%的几种寡糖文库，并使用“还原裂解”方法鉴定文库中存在的各个位置异构体。
