Département de chimie moléculaire

Two series of multivalent octasilsesquioxane glyco- and peptido-conjugates were synthesized using the photoinduced free-radical thiol-ene coupling (TEC). The first series was obtained by coupling C-glycosylpropyl thiols and cysteine contg. peptides with the known octavinyl octasilsesquioxane, while the second series was obtained by reacting glycosyl thiols with a new octasilsesquioxane deriv. displaying eight PEGylated chains functionalized with terminal allyl groups. The evaluation of the binding properties of mannoside and glucoside clusters toward Con A by Enzyme-Linked Lectin Assay (ELLA) revealed a modest glycoside cluster effect. However, the PEGylated POSS-based glycocluster featuring eight N-acetyl-glucosamine residues showed high affinity toward Wheat Germ Agglutinin to give a measured IC50 at 3 nM. The calcd. relative potency per no. of sugar unit (rp/n) was superior to a value of 106, thus revealing the occurrence of a striking glycoside cluster effect. [on SciFinder(R)]