New highly hydrophobic Lewis X glycolipids: Synthesis and monolayer behaviour

Two highly hydrophobic Lewis X glycolipids 2 and 3 were prepared. The glyco conjugate 2 was constructed in the following way: pentaerythrytol was used as a distributor on which three racemic phytol hydrophobic chains and a tri ethyleneglycol spacer beta -glycosylated with the pentasaccharide Gal (beta 1-4)[Fuc (alpha 1-3)] GlcNAc (beta 1-3) Gal (beta 1-4) Glc were anchored. The glycoconjugate 3 was constructed in a similar way, the sugar moiety bei ng the trisaccharide Gal (beta 1-4)[Fuc (alpha 1-3)] GlcNAc, the so-called Lewis X determinant. A triethyleneglycol spacer was used in order to introd uce the mobility required for the study of single carbohydrate-carbohydrate interactions. Three phytyl chains increase the hydrophobicity of the lipid moiety compared to the natural ceramide glycolipid 1. These glycolipids di splay a liquid-expanded behaviour with a high compressibility in monolayer studies. These properties associated with a low solubility in water make th em good candidates for the study of the interaction between two Lewis X fun ctionalized vesicles.