Synthesis of Simple Multivalent β-D-GalNAc-(1→4)-β-D-Gal Oligomers as Probes for Investigating the Interactions ofP. AeruginosaPili with Multivalent Receptors

A facile synthesis of the GalNAcβ1→4Gal target sequence of respiratory pathogens

The carbohydrate sequence, GalNAcbeta1-->4Gal, is the target for the adhesion of several respiratory pathogens. The sequence was prepared in an optimized synthesis in forms that allow conjugation to scaffolds or surfaces.

Adhesion Inhibition of F1C-Fimbriated Escherichia coli and Pseudomonas aeruginosa PAK and PAO by Multivalent Carbohydrate Ligands

In order to evaluate their inhibition of bacterial adhesion, the carbohydrate sequences GalNAcbeta1-->4Gal and GalNAcbeta1-->4Galbeta1-->4Glc were synthesized. The disaccharide was conjugated to dendrons based on the 3,5-di-(2-aminoethoxy)-benzoic acid branching unit to yield di- and tetravalent versions of these compounds. A divalent compound was also prepared that had significantly longer spacer arms. Relevant monovalent compounds were prepared for comparison. Their anti-adhesion properties against F1C-fimbriated uropathogenic Escherichia coli were evaluated in an ELISA-type assay by using a recombinant strain and also by using Pseudomonas aeruginosa strains PAO and PAK. Adhesion inhibition was observed in all cases, and multivalency effects of up to one order of magnitude were observed. The combination of spacer and multivalency effects led to a 38-fold increase in the potency of a divalent inhibitor with long spacer arms towards the PAO strain when compared with the free carbohydrate.

Syntheses of model compounds related to an antigenic epitope in pectic polysaccharides from Bupleurum falcatum L

Stereocontrolled syntheses of model compounds related to a category of the major antigenic epitope against anti-bupleurum 2IIc/PG-1-IgG from an anti-ulcer pectic polysaccharide are described. Glycosylation of the glucuronic acid donors methyl(2,3-di-O-benzoyl-4-O-methyl-alpha-D-glucopyranosyl trichloroacetimidate)uronate and methyl (2,3-di-O-benzoyl-4-O-methyl-beta-D-glucopyranosyl)uronate-(1-->6)-2,3,4-tri-O-benzoyl-alpha-D-galactopyranosyl trichloroacetimidate with the common acceptor 2-(trimethylsilyl)ethyl 2,3,4-tri-O-benzyl-beta-D-galactopyranoside in the presence of trimethylsilyl triflate (TMSOTf) gave the desired di- and trisaccharide derivatives. Furthermore the products were transformed into the oligo-valent clustering saccharides, N,N',N"-tri-(5-[4-O-methyl-beta-D-glucopyranosyluronic acid-(1-->6)-beta-D-galactopyranosyloxy]pentylcarbonylaminoethyl)-1,3,5-benzenetriamide and N,N',N"-tri-(5-[4-O-methyl-beta-D-glucopyranosyluronic acid (1-->6)-beta-D-galactopyranosyl-(1-->6)-beta-D-galactopyranosyloxy]pentylcarbonylaminoethyl)-1,3,5-benzenetriamide.

Synthetic studies on dendritic glycoclusters: a convergent palladium-catalyzed strategy

A facile Pd-catalyzed strategy by which multiantennary glycoclusters and sugar dendrons can be readily assembled in one-step is described.