生体機能の解明とその応用を目指すシアロ複合糖質「ガングリオシド」の系統的合成

抄録

The facile regio- and stereo-controlled α-glycosidations of sialic acid (Neu5Ac) are now well studied by using the thioglycosides of Neu5Ac as glycosyl donors, and suitably protected sugar residues as glycosyl acceptors. High yields of desired products are possible either by using DMTST or NIS/TfOH as thiophilic promoters in acetonitrile. A variety of gangliosides, such as GM₄, GM₃, GM₂, GM_1a, GM_1b, GD_1a, GD_1α, GD₃, lacto- and neolacto-series gangliosides, and their isomers, have systematically been synthesized by a series of reactions which start from the condensation of sialo-oligosaccharides and 2-azido-sphingosine. Various analogs and derivatives of gangliosides containing thioglycosidic linkage (s), modified sialic acids and pseudo-ceramides have also been synthesized. Recent advance in the biomedical studies using synthetic gangliosides, especially sialyl Le^x and its related carbohydrate ligands, is also described.