Systematic synthesis of N-methyl-1-deoxynojirimycin-containing, Le(x), Le(a), sialyl-Le(x) and sialyl-Le(a) epitopes recognized by selectins.

A systematic synthesis of the N-methyl-1-deoxynojirimycin-containing oligosaccharides related to the Lewis x, Lewis a, sialyl-Lewis x and sialyl-Lewis a antigens has been achieved. The couplings of the suitably protected 1-deoxynojirimycin derivative 10 with methyl-1-thioglycosides (glycosyl donors) of L-fucose (11), D-galactose (15) and alpha-sialyl-(2-->3)-D-galactose (27) were carried out by using dimethyl(methylthio)sulfonium triflate (DMTST) or N-iodosuccinimide/trifluoromethanesulfonic acid (NIS/TfOH) as the glycosyl promoter. The resulting di- and tri-saccharides were each converted, by further cross glycosylations with 11, 15 or 27, to the desired tri- and tetra-saccharides 3-6 that inhibit the recognition between sialyl-Lewis x and selectins, a family of leukocyte cell adhesion molecules.