Glycoclusters presenting lactose on calix[4]arene cores display trypanocidal activity
摘要:
A new series of water-soluble tetravalent glycoclusters incorporating beta-lactosyl residues attached to a central calix[4]arene core was synthesised using azide-alkyne Cu(I)-catalysed cycloaddition ('click chemistry'). Carbohydrate moieties were attached either to the upper or lower rim of rigid cone-shaped or partial cone macrocycles via 14-21 atom spacer arms. The glycoclusters with a C(4)-symmetrical arrangement of beta-lactosyl residues showed trypanocidal activity, with one of them showing comparable activity to established anti-trypanosomal drug benznidazole in in vitro anti-parasite assays. (C) 2011 Elsevier Ltd. All rights reserved.
Synthesis of Glycodendrimers by Modification of Poly(propylene imine) Dendrimers
摘要:
AbstractThe use of preformed poly‐(propylene imine) dendrimers (DAB‐dendr‐(NH2)x) for the rapid and facile construction of high molecular weight carbohydrate‐coated dendrimers (glyco‐dendrimers) is presented. An efficient attachment of spacer‐armed derivatives of D‐galactose and lactose to the primary amino end groups of DAB‐dendr‐(NH2)x has been achieved by means of amide bond formation, using the N‐hydroxysuccinimide coupling procedure. Acetate protecting groups have been employed in order to avoid side reactions at the coupling stage. Deacetylation leads to the target glycodendrimers. The reactivity of all the available DAB‐dendr‐(NH2)x (generations 1–5) has been investigated and a series of homologous carbohydrate‐coated dendrimers have been synthesized. In addition, the attachment of larger saccharide moieties has been demonstrated by the condensation of a trisgalactoside cluster with DAB‐dendr‐(NH2)x carrying both four and eight primary amino groups. The regularity of the glycodendrimers has been proven by NMR spectroscopy, and the molecular weights of the low‐generation carbohydrate‐coated dendrimers have been determined by mass spectrometry. Modifications of DAB‐dendr‐(NH2)x with biologically active carbohydrates affords a new and simple approach to high molecular weight compounds that may be considered as neoglycoconjugates with perfectly symmetrical structures and that offer much promise as multivalent ligands involved in carbohydrate‐protein interactions.