Photoinitiated Thiol-Ene Reactions of Various 2,3-Unsaturated O-,C- S- and N-Glycosides – Scope and Limitations Study

The photoinitiated thiol-ene addition reaction is a highly stereo- and regioselective, and environmentally friendly reaction proceeding under mild conditions, hence it is ideally suited for the synthesis of carbohydrate mimetics. A comprehensive study on UV-light-induced reactions of 2,3- unsaturated O-, C-, S- and N-glycosides with various thiols was performed. The effect of experimental parameters and structural variations of the alkenes and thiols on the efficacy and regio- and stereoselectivity of the reactions was systematically studied and optimized. The type of anomeric heteroatom was found to profoundly affect the reactivity of 2,3-unsaturated sugars in the thiol-ene couplings. Hydrothiolation of 2,3-dideoxy O-glycosyl enosides efficiently produced the axially C2-S-substituted addition products with high to complete regioselectivity. Moderate efficacy and varying regio- and stereoselectivity were observed with 2,3- unsaturated N-glycosides and no addition occurred onto the endocyclic double bond of C-glycosides. Upon hydrothiolation of 2,3-unsaturated S-glycosides, the addition of thiyl radicals was followed by elimination of the thiyl aglycone resulting in 3-S-substituted glycals

Investigation of binding affinity of a broad array of L-fucosides with six fucose-specific lectins from bacterial and fungal origin

Series of multivalent α-L-fucoside containing glycoclusters and variously decorated L-fucosides were synthesized to find potential inhibitors of fucose-specific lectins and study the structure-binding affinity relationships. Tri- and tetravalent fucoclusters were built up using copper-mediated azide-alkyne click chemistry. Series of fucoside monomers and dimers were synthesized using various methods, namely glycosylation, azide-alkyne click reaction, photoinduced thiol-en addition and sulfation. The interactions of compounds with six fucolectins of bacterial or fungal origin were tested using hemagglutination inhibition assay. As a result, a tetravalent, α-L-fucose presenting glycocluster showed to be orders of magnitude better ligand than a simple monosaccharide for tested lectins in most cases, which can nominate it as a universal ligand for studied lectins. This compound was also able to inhibit adhesion of Pseudomonas aeruginosa cells to human epithelial bronchial cells. A trivalent fucocluster with protected amine functional group seems also to be a promising candidate to design glycoconjugates and chimeras

Photoinitiated Thiol-Ene Reactions of Various 2,3-Unsaturated O-, C- S- and N-Glycosides: scope and Limitations Study

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Investigation of the Binding Affinity of a Broad Array of l-Fucosides with Six Fucose-Specific Lectins of Bacterial and Fungal Origin

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Comparative biocompatibility and antimicrobial studies of sorbic acid derivates

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