SYNTHESIS OF SIALYL-LEWIS-X GANGLIOSIDE ANALOGS CONTAINING A VARIABLE-LENGTH SPACER BETWEEN THE SUGAR AND LIPOPHILIC MOIETIES

Five sialyl Lewis X ganglioside analogs containing 4-(2-retradecylhexa decanoylamino)benzyl group in place of ceramide and a variety of lengt hs of ethylene glycol chains as the spacer, have been synthesized. Gly cosidation of O-(methyl 5-acetamido-4,7,8,9-tetra-O- acetyl-3, cero-al pha-D-galacto-2-nonulopyranosylonate)-(2--> 3)-O-(4-O-acetyl-2, 6-di-O -benzoyl-beta-D-galactopyranosyl)-(1 -->4)-O-[(2,3,4-tri-O-acetyl alph a-L-fucopyranosyl) -(1-->3)]-2,4-di-O-benzoyl-alpha-D-glucopyranosyl t richloroacetimidate (13) with oligo ethyleneglycol monobenzyl ether de rivatives 9, 10, 11 and 12, prepared from the corresponding oligo ethy leneglycols by 4-nitrobenzylation, reduction and N-acylation with 2-te tradecylhexadecanoic acid, using boron trifluoride etherate gave the c orresponding glycolipid derivatives 14, 15, 16 and 17. A similar glyco sidation of 13 with 4-nitrobenzyl alcohol gave the 4-nitrobenzyl glyco side 18, which was converted via reduction of nitro group and N-acylat ion into the corresponding glycolipid derivative 19. Compounds 14-17 a nd 19 were transformed into the title compounds by O-deacylation and h ydrolysis of methyl ester group in good yields.