7 Trypanosoma bruceiのグリコシルホスファチジルイノシトール(GPI)アンカーに関する合成研究(口頭発表の部)

抄録

Glycosyl-phosphatidylinositol (GPI) anchor, which attaches many surface proteins to cell membrane is a novel glycolipid composed of phosphatidylinositol, non-acetylated glucosamine, oligosaccharide, and ethanolamine linked by a phosphodiester bond. Recently, it was suggested that GPI anchor was involved in signal transduction of insulin as well as Qa-2 mediated T-cell activation. We will present here a first total synthesis of GPI anchor present on a variant surface glyco-protein (VSG) of the parasitic protozoan Trypanosoma brucei. Glycoheptaosyl core 2 of the target molecule 1 was designed to be constructed from glycotriosyl acceptor 5, galactobiosyl donor 6, and two mannosyl donors 7 and 8. The key intermediate 5, which was prepared from optically active inositol synthon 9, glycosamine synthon 10, and mannose synthon 11 was coupled with 6 in the presence of Cp2ZrCl2-AgClO4 to yield 24. Glycopentaoside 24 was converted into glycoheptaoside 28, which was reacted with 29 to give 2. Finally, introduction of two phosphodiester functions into 2 was achieved by employing H-phosphonate method to afford GPI anchor 1.