The synthesis of some deoxygenated analogues of early intermediates in the biosynthesis of glycosylphosphatidylinositol (GPI) membrane anchors

Graphic Syntheses are described of 2-azido-4,6-di- O-benzyl-2,3-dideoxy- d- ribo-hexopyranosyl fluoride, 6- O-acetyl-2-azido-3- O-benzyl-2,4-dideoxy- d- xylo-hexopyranosyl fluoride and 2-azido-3,4-di- O-benzyl-2,6-dideoxy- d-glucopyranosyl fluoride. These glycosyl donors were coupled with the acceptor 1 d-2,3,4,5-tetra- O-benzyl-1- O-(4-methoxybenzyl)- myo-inositol and the α-coupled products were transformed into α- d-3dGlc pN-PI, α- d-4dGlc pN-PI and α- d-6dGlc pN-PI by way of the H-phosphonate route. Brief mention is made of the biological evaluation of these deoxy-sugar analogues and their N-acetylated forms as candidate substrate/inhibitors of the N-deacetylase and α-(1→4)- d-mannosyltransferase activities present in trypanosomal and HeLa (human) cell-free system.