[reaction: see text] The construction of multivalent neoglycoconjugates is efficiently achieved by the regiospecific catalytic cycloaddition of alkynes and azides using the organic-soluble copper complexes (Ph(3)P)(3).CuBr and (EtO)(3)P.CuI. The simultaneous use of microwave irradiation shortened notably the reaction times.

The easy functionalization of tags and solid supports with the vinyl sulfone function is a valuable tool in omic sciences that allows their coupling with the amine and thiol groups present in the proteogenic residues of proteins, in mild and green conditions compatible with their biological function.

The covalent immobilization of suitable alkyne/azide carbohydrate derivatives on complementarily functionalizated azide/alkyne silica was performed by click ligation througth the Cu(I)-catalyzed 1,3-dipolar cycloaddition reaction of such compounds. The new glyco-silicas have shown to be efficient and valuable bio-selective affinity chromatographic supports for the purification of lectins as well as for the one-pot fluorescent labeling of those proteins. The synthetic methodology is simple, high yielding and flexible, allowing the preparation of tailored glyco-silicas with potential future applications in the inmobilization of other biomolecules.

The efficient synthesis of fluorescent and non-fluorescent multivalent neoglycoconjugates is described by means of the Cu(i) catalyzed azide-alkyne 1,3-dipolar cycloaddition ("click-chemistry"). A well-defined glycopolymer, glycocyclodextrin or glycocluster architecture displaying galactose or lactose epitopes has been chosen. Cellular assays using U-937 and RAW 264.7 monocyte/macrophage cells showed that these glycocompounds have the capability to act as synthetic activators mimicking the lipopolysaccharide (LPS) effects. Thus, the click compounds promote cell adhesion and stimulation of monocytes, measured as an increase in the amount of TNFalpha, facilitating their differentiation to macrophages.

No abstract

Abstract:The aim of this study was to evaluate the crosslinking abilities of divinyl sulfone (DVS) for the preparation of novel water-insoluble cyclodextrin-based polymers (CDPs) capable of forming inclusion complexes with different guest molecules. Reaction of DVS with native α-cyclodextrin (α-CD), β-cyclodextrin (β-CD) and/or starch generates a variety of homo-and hetero-CDPs with different degrees of crosslinking as a function of the reactants' stoichiometric ratio. The novel materials were characterized by powder X-ray diffraction, electron microscopy and for their sorption of phenol and 4-nitrophenol. They were further evaluated as sorbents with phenolic pollutants (bisphenol A and β-naphthol) and bioactive compounds (the hormone progesterone and curcumin). Data obtained from the inclusion experiments show that the degree of cross-linking has a minor influence on the yield of inclusion complex formation and highlight the important role of the CDs, supporting a sorption process based on the formation of inclusion complexes. In general, the inclusion processes are better described by a Freundlich isotherm although an important number of them can also be fitted to the Langmuir isotherm with R 2 ≥ 0.9, suggesting a sorption onto a monolayer of homogeneous sites.

Novel supported chelating adsorbents bearing diverse multidentate nitrogenated ligands with strong copper(I) affinities are easily prepared in non-magnetic and magnetic variants using silica and silica-coated magnetite nanoparticles as suitable supports and the aza-Michael-type addition of vinyl sulfones as the ligation tool. These adsorbents are versatile materials with applications in the copper-catalyzed alkyne-azide cycloaddition (CuAAC) click chemistry where their complexation abilities enable them to act either as heterogeneous click catalysts when used in their complexed form or as copper(I) scavengers when used in their uncomplexed form. In the first instance, they proved to be robust and efficient heterogeneous catalysts to promote click reactions using extremely low doses and showing negligible copper leaching, particularly in the case of the silica-based non-magnetic adsorbents, allowing a simple operational protocol for their rapid and easy removal by filtration or magnetic decantation and showing good recyclability properties. In their uncomplexed form, the non-magnetic chelating adsorbents are very efficient copper scavengers that are able to remove any traces of metal contamination and that can be applied in tandem with any heterogeneous supported copper(I) catalysts or as standalone copper removing system in any click protocol allowing the isolation of metal-free clicked compounds.

The construction of multivalent structures such as sugar heterodimers, glycoclusters, calix sugars, multicalixarenes, and glycocyclodextrins is designed by using 1,3-dipolar cycloaddition as a versatile and efficient tool which allows the creation of heterocyclic bridges between the different units that are coupled.