Synthesis of novel ganglioside GM4 analogues containing N-deacetylated and lactamized sialic acid: probes for searching new ligand structures for human L-selectin Original Research Article

Novel ganglioside GM4 analogues, which contain N-deacetylated or lactamized sialic acid instead of usual N-acetylneuraminic acid, were synthesized in a highly efficient manner. (Methyl 4,7,8,9-tetra-O-acetyl-3,5-dideoxy-5-trifluoroacetamido-d-glycero-α-d-galacto-2-nonulopyranosylonate)-(2→3)-4,6-di-O-acetyl-2-O-benzoyl-d-galactopyranosyl trichloroacetimidate was coupled with 2-(tetradecyl)hexadecanol to give the desired β-glycoside in high yield. Successive O- and N-deacylation, and saponification of the methyl ester group afforded the N-deacetylated sialyl derivative that was converted by treatment with 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride in Me2SO into the lactamized sialic acid-containing ganglioside GM4 analogue.