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[Display omitted] • A known sialyl thioglycoside was converted to the corresponding oxazolidinone derivative. • Further chemical modification of the oxazolidinone afforded the precursor Neu5Gc derivative. • Glycosidation of the thioglycoside with various simple alcohols yielded the desired α-glycosides in good yields. • Structural elucidation of the glycosides was performed by 1H NMR, 13C NMR, and HMBC. An efficient synthesis of lauryl thioglycoside of oxazolidinones derived from N -acetyl neuraminic acid was accomplished from a known thioglycoside of Neu5Ac. The O -glycosidation reactivities of the oxazolidinones were evaluated by means of trimethylsilyl trifluoromethanesulfonate (TMSOTf) and N -iodosuccinimide (NIS) as a combined-mediator system. The glycosidation reaction of the lauryl thioglycoside with simple alcohols proceeded smoothly to yield the corresponding α-glycosides in good yields after isolation. The results suggested that the glycosylation reaction using the oxazolidinone derivative of sialic acid has excellent α-stereoselectivity and enables easy isolation of the desired product from the reaction mixture. [ABSTRACT FROM AUTHOR]

Highlights: [•] Saccharidic chiral dopants for nematic liquid crystals were synthesized from d-glucose. [•] The helical twisting power (HTP) values were evaluated. [•] The chiral dopants induced helices in the host nematic liquid crystals. [•] No relationship between HTP and specific rotation on the chiral dopants was observed in this study. [Copyright &y& Elsevier]

A polymerizable alcohol having 9 PEG repeats was prepared in order to mimic an oligosaccharide moiety. Sialyl α(2→3) lactose, which is known as a sugar moiety of GM3 ganglioside, was also prepared, and the polymerizable alcohol was condensed with the sialyl α(2→3) lactose derivative to afford the desired glycomonomer, which was further polymerized with or without acrylamide to give water-soluble glycopolymers. The glycopolymers had higher affinities than those of glycopolymers having sialyl lactose moieties with shorter aglycon moieties. [ABSTRACT FROM AUTHOR]

The thioglycoside of Neu5Gc unit was synthesized from the Neu5Ac derivative in 4 steps. The thioglycoside of Neu5Gc as a glycosyl donor was allowed to react with various alcohols to afford the corresponding glycosides. [Display omitted] • A Neu5Gc unit was prepared from a Neu5Ac derivative. • Thioglycoside of Neu5Gc was synthesized as a glycosyl donor. • Glycosidation of the Neu5Gc derivative gave the desired Neu5Gc-related compound. • Reaction properties of the thioglycoside of Neu5Gc were investigated. Efficient synthesis of lauryl thioglycoside of Neu5Gc was accomplished from a known thioglycoside of Neu5Ac. The reactivities of the Neu5Gc thioglycoside for O -glycosidation by means of TMSOTf-NIS as a promoter system were investigated, and the thioglycoside showed good activities with simple alcohols. In addition to the simple alcohols, the reactivities of lauryl thioglycoside of Neu5Gc were also evaluated with glucose and lactose derivatives and the results suggested that the thioglycoside is a potential candidate for glycosidation as the glycosyl donor. [ABSTRACT FROM AUTHOR]

• Two polymers having α-mannoside moieties or dansyl fluorophores were conventionally prepared. • Efficient synthesis of glycopolymers having α-mannoside moieties and the fluorophores was accomplished. • Biological evaluations of glycopolymers—lectin interactions were performed. • Intermolecular FRET was clearly observed when fluorogenic glycopolymers were used. Quantitative evaluations of the binding affinities between glycopolymers and lectins in order to investigate the functionality of glycopolymers are of great importance. In this study, we developed fluorogenic glycopolymers that induce Förster resonance energy transfer (FRET) upon binding to lectins and we attempted directly to monitor the interaction followed by evaluation of the binding affinity on the basis of intermolecular FRET. Water-soluble glycopolymers with various polymer compositions containing mannose moieties as ligands for a lectin and dansyl moieties as fluorogenic chromophores for the FRET system were prepared, and the binding constant K a (M−1) with concanavalin A (Con A; mannose-binding lectin) was estimated on the basis of the change in fluorescence intensity caused by FRET. Fluorescence measurements revealed intermolecular FRET between the fluorogenic glycopolymer and Con A, and the binding constants were estimated to be 0.398×106 ∼ 2.40×106 (M−1). The results suggested that this method can be applied to evaluation of the interaction when the binding of a glycopolymer to a lectin results in little fluorescence change. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Fischer's glycoside synthesis effectively worked with alcohols with longer aliphatic chains. • Glycopolymers having α-glycoside-type GlcNAc moieties were prepared. • Sugar densities on the glycopolymers were controlled. • Biological evaluations of glycopolymers—WGA were tested. • Glycopolymer having an appropriate sugar-density showed the highest affinity. Fischer's glycoside synthesis was applied to linker precursor alcohols of two different lengths having appropriate alkane chains to obtain the corresponding α-glycoside and it was found to be applicable with moderate yields. Water-soluble glycomonomers were systematically prepared from N -acetyl- d -glucosamine (GlcNAc) by introducing two kinds of alcohols having different methylene lengths. Typical radical polymerizations of the glycomonomers with acrylamide as a modulator for control of the distance between carbohydrate residues in water in the presence of ammonium persulfate (APS)- N , N , N' , N' -tetramethylethylenediamine (TEMED) gave a series of glycopolymers with various α-glycoside-type GlcNAc residue densities. Fluorometric analysis of the interaction of wheat germ agglutinin (WGA) with the glycopolymers was performed and the results showed unique binding specificities based on structural differences. [ABSTRACT FROM AUTHOR]

Bivalent glycoconjugates have a minimal valence with avidity potential on protein-carbohydrate interactions as well as simplicity of chemical structures enabling simple synthesis with low cost. Understanding the way to maximize the affinities of bivalent glycoconjugates is important for the development of cost-effective tools for therapeutic and diagnostic research. However, there has been little discussion about the effects of constraints imposed from ligand scaffolds on the binding abilities. We synthesized three kinds of biantennary N -acetylglucosamine glycosides with different scaffolds using isobutenyl bis(propargyl)ether as a common scaffold precursor. Decoration of the scaffold branches with GlcNAc moieties through copper-catalyzed azide-alkyne cycloaddition and grafting of the alkenyl focal point to another bivalent biotin dendron through thiol-ene and nucleophilic substitution reactions were successfully carried out in an orthogonal manner. The association constants of the ligands against wheat germ agglutinin were determined by a fluorometric titration assay. A bivalent biotin counterpart provided higher affinity than an isobutyl scaffold, whereas an isobutenyl scaffold yielded more enhancement than a bivalent biotin counterpart. The present work suggested that the constraint and steric bulk of ligand scaffolds are possible factors for improving binding properties of glycoconjugates against lectins or proteins. [ABSTRACT FROM AUTHOR]

[Display omitted] Glycopolymers having sialyl α2-3 lactose moieties via longer spacer arms were systematically prepared from the corresponding glycomonomers. Radical polymerization of glycomonomers gave a series of glycopolymers displaying various sugar densities. Fluorometric analyses of wheat germ agglutinin (WGA) against the glycopolymers were conducted and the results showed unique binding specificities on the basis of sugar densities. [ABSTRACT FROM AUTHOR]

Highlights: [•] Chloromethylstyrene and N-acetyl-d-glucosamine (GlcNAc) were used for this study. [•] Simple modification of the starting materials gave the water-soluble glycomonomer. [•] A convenient access for glycopolymers was accomplished by radical polymerization. [•] The glycopolymers exhibited high affinity against WGA. [ABSTRACT FROM AUTHOR]

[Display omitted] • Glycopolymer having GlcNAc moieties was prepared. • Sugar densities on the glycopolymers were controlled. • Degree of freedom of GlcNAc residue on the glycopolymers was controlled. • Biological evaluations of glycopolymers—lectin were performed. Four kinds of water-soluble carbohydrate monomers having different methylene numbers of polymerizable aglycons were systematically prepared from N -acetyl-D-glucosamine (GlcNAc). Typical radical polymerization in the presence of ammonium persulfate (APS)—tetramethylethylenediamine (TEMED) in water was applied for the monomers with acryl amide as a regulator for adjusting the average distance between carbohydrate residues, a series of glycopolymers having various densities of GlcNAc residues was obtained. Regulation of the polymers showed two pivotal points: one is the effect of lengths between carbohydrate residues and the polymer backbone and the other one is the influence of average densities of carbohydrates in the glycopolymer. Carbohydrate—protein interaction by means of the glycopolymer library for wheat germ agglutinin (WGA) as a model protein was investigated and the highest K a value was obtained when the glycopolymer having the longest methylene length and the ratio of 1:10 (sugar unit:acrylamide unit) was used as a substrate. [ABSTRACT FROM AUTHOR]

Abstract: Synthetic construction of fucosyl chitobiose [GlcNAcβ1→4(Fucα1→3)GlcNAc] as an allergy-associated carbohydrate epitope was accomplished from three building blocks. The trisaccharidic unit was further transformed into a carbohydrate monomer and polymerization of the glycomonomer proceeded smoothly to provide a series of glycopolymers having various carbohydrate densities. In addition to the organic syntheses, biological evaluations of the glycomonomer and the polymers were carried out and sugar-clustering effects were observed. [Copyright &y& Elsevier]

[Display omitted] • A hydrophobic Pba and a hydrophilic glycomonomer were polymerized. • The polymerization gave the corresponding water-soluble glycopolymer having Pba moieties. • Structural elucidation of the polymer was performed by 1H NMR. • The thermal property of the polymers was evaluated on the basis of TG-DTA measurement. • Uv–vis spectroscopic analysis of the polymer showed the characteristic absorption due to Pba. The first trial of incorporation of pheophorbide a (Pba) into a synthetic glycopolymer giving water-soluble ability was carried out, and the polymerization reaction of each monomer proceeded in DMSO to afford the desired glycopolymer having Pba side chains. Characterization of the polymer was performed by means of spectroscopic analyses and thermal studies, and the results supported the desired macromolecular architecture. [ABSTRACT FROM AUTHOR]

Convenient access of a glycopolymer having N -acetyl- D -glucosamine (GlcNAc) residues was accomplished by means of radical polymerization of a simple GlcNAc monomer with or without acrylamide. Biological evaluations of glycopolymers displaying various carbohydrate contents were carried out by using fluorometric assays, and the results suggested that ratio of the sugar unit: acrylamide had a significant relation to affinities between carbohydrate—protein interactions. In this study, the unit ratio of 1:11.5 of carbohydrate: acrylamide was found to be the best ratio. Image 1 • A glycomonomer having GlcNAc was conventionally synthesized. • A series of glycopolymers having various densities of GlcNAc moieties was prepared. • Biological evaluations of glycopolymers—lectin were performed. • The contents of carbohydrate moieties—activity relationship of glycopolymers—lectin was investigated. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Sugar-amino acid hybrid monomers were prepared. • Assembly of the monomers was accomplished by radical polymerization. • Affinities of the polymers against Stxs were examined. • High cluster-type polymers showed higher affinity than low cluster-type polymers. Abstract Synthetic assembly of sugar moieties and amino acids in order to create "sugar-amino acid hybrid polymers" was accomplished by means of simple radical polymerization of carbohydrate monomers having an amino acid-modified polymerizable aglycon. Amines derived from globotriaoside and lactoside as glycoepitopes were condensed with known carbobenzyloxy derivatives, including Z-Gly, Z- l -Ala and Z-β-Ala, which had appropriate spacer ability and a chiral center to afford fully protected sugar-amino acid hybrid compounds in good yields. After deprotection followed by acryloylation, the water-soluble glycomonomers were polymerized with or without acrylamide in the presence of a radical initiator in water to give corresponding copolymers and homopolymers, which were shown by SEC analysis to have high molecular weights. Evaluation of the biological activities of the glycopolymers against Shiga toxins (Stxs) was carried out, and the results suggested that glycopolymers having highly clustered globotriaosyl residues had high affinity against Stx2 (K D = 2.7∼4.0 µM) even though other glycopolymers did not show any affinity or showed very weak binding affinity. When Stx1 was used for the same assay, all of the glycopolymers having globotriaosyl residues showed high affinity (K D = 0.30∼1.74 µM). Interestingly, couple of glycopolymers having lactosyl moieties had weaker binding affinity against Stx1. In addition, when cytotoxicity assays were carried out for both Stxs, glycopolymers having highly clustered globotriaosyl residues showed higher affinity than that of the copolymers, and only highly clustered-type glycopolymers displayed neutralization potency against Stx2. [ABSTRACT FROM AUTHOR]

[Display omitted] • NMR analyses of CNN and its derivatives were performed. • Verification of standard acetylation for CNN was performed. • Complete protection of CNN was efficiently performed. Verification of acetylation by means of pyr—Ac 2 O for a cyclic α-nigerosyl-(1 → 6)-nigerose (CNN) was performed and the corresponding mono alcohol was obtained. Structural elucidation of CNN derivatives was carried out on the basis of NMR spectroscopic analyses. Complete protection by means of esterification and methylation was efficiently accomplished to yield fully protected compounds, and the results of NMR spectroscopic analyses of the products supported the perfect progress of the reaction. [ABSTRACT FROM AUTHOR]

Convenient and useful construction of a trisaccharide moiety of globotriaosyl ceramide was performed by means of modified Ogawa’s protocol. In order to evaluate an efficiency of new class of glycopolymers, further chemical transformations of the trisaccharide were accomplished to afford a globotriaosyl carbohydrate monomer, and homopolymerization of the monomer by a general radical polymerization protocol gave a high-density glycopolymer in 84.3% yield after usual work-up procedures. In addition to the homopolymer, a copolymer composed of carbohydrate units and acrylamide units was also synthesized by the radical polymerization in 96.7% yield. [Copyright &y& Elsevier]

As an artificial ligand, a glycoconjugate polymer carrying carbohydrate moiety of lactosyl ceramide or globotriaosyl ceramide (Gb3) was synthesized. Gb3 is known as the receptor of Shiga toxin-producing Escherichia coli O157: H7. The preparation of the glycoconjugate polymer initially involves the construction of the carbohydrate moiety of Gb3 derivative which has n-pentenyl group as polymerizable group. In addition, the n-pentenyl group of the Gb3 derivative was modified and different polymerizable groups such as acrylamide group were introduced at ω-position of the aglycon. Radical polymerization of the synthesized glycosyl monomers with or without acrylamide proceeded smoothly in water using ammonium persulfate and N, N, N′, N′-tetramethylethylenediamine as usual initiator system and gave water-soluble glycoconjugate polymers having various polymer compositions. These polymers have the potential to neutralize Shiga toxin by reason of cluster effect and multivalency. [Copyright &y& Elsevier]