64552-06-3

Upstream product

• 100-52-7 benzaldehyde 
• 3396-99-4 methyl α-D-galactopyranoside 
• 774-48-1 (diethoxymethyl)benzene 
• 181480-80-8 6-O-tert-butyldimethylsilanyl-1-O-methyl-α-D-galactopyranoside 
• 51223-62-2 methyl β-D-galactopyranoside 
• 1125-88-8 benzaldehyde dimethyl acetal 
• 617-04-9 (2R,3S,4S,5S,6S)-2-(hydroxymethyl)-6-methoxytetrahydro-2H-pyran-3,4,5-triol 
• 2774-22-3 2,3-O-diacetyl-(4,6-O-benzylidene)methyl-α-D-mannopyranoside 
• 65530-27-0 (2R,4aR,6S,8aS)-(+)-6-methoxy-2-phenyl-4,4a,6,8a-tetrahydropyrano[3,2-d][1,3]dioxine 
• 22277-65-2 Methyl mannoside 
• 3162-96-7 methyl 4,6-O-benzylidene-β-D-galactopyranoside 
• 82430-07-7 (2R,4S,5R)-5-((R)-1-Methoxy-2-oxo-ethoxy)-2-phenyl-[1,3]dioxane-4-carbaldehyde 
• 82430-07-7 (4S,5R)-5-((R)-1-Methoxy-2-oxo-ethoxy)-2-phenyl-[1,3]dioxane-4-carbaldehyde 
• 1824-94-8 methyl beta-D-galactopyranoside 

Downstream Products

• 620173-69-5 methyl 2,3-di-O-acetyl-4,6-O-benzylidene-α-D-galactopyranoside 
• 86420-70-4 methyl 2-O-benzoyl-4,6-O-benzylidene-α-D-galactopyranoside 
• 86420-71-5 methyl 3-O-benzoyl-4,6-O-benzylidene-α-D-galactopyranoside 
• 120201-28-7 methyl 2,3-di-O-benzoyl-4,6-O-benzylidene-α-D-galactopyranoside 
• 86420-74-8 methyl 4,6-O-benzylidene-2,3-di-O-benzoyl-β-D-galactopyranoside 
• 86420-66-8 methyl 4,6-O-benzylidene-α-D-galactopyranoside 2,3-di-O-p-toluenesulfonate 
• 86420-67-9 methyl 4,6-O-benzylidene-α-D-galactopyranoside 2-O-p-toluenesulfonate 
• 86420-68-0 methyl 4,6-O-benzylidene-α-D-galactopyranoside 3-O-p-toluenesulfonate 
• 3013-58-9 methyl 4,6-O-benzylidene-2,3-di-O-methyl-α-D-galactopyranoside 
• 18423-93-3 methyl-[O³-ethoxycarbonyl-O⁴,O⁶-((S)-benzylidene)-α-D-galactopyranoside] 
• 18423-91-1 methyl-[O²,O³-bis-ethoxycarbonyl-O⁴,O⁶-((S)-benzylidene)-α-D-galactopyranoside] 
• 116002-34-7 methyl 4,6-O-benzylidene-α-D-galactopyranoside 2-O-benzoate 
• 156924-97-9 methyl 4,6-O-benzylidene-α-D-galactopyranoside 3-O-benzoate 
• 7177-79-9 methyl 2,3-di-O-benzyl-4,6-O-(S)-benzylidene-α-D-galactopyranoside 

Relevant academic research and scientific papers

N -Glycosylation with sulfoxide donors for the synthesis of peptidonucleosides

The synthesis of glycopyranosyl nucleosides modified in the sugar moiety has been less frequently explored, notably because of the lack of a reliable method to glycosylate pyrimidine bases. Herein we report a solution in the context of the synthesis of peptidonucleosides. They were obtained after glycosylation of different pyrimidine nucleobases with glucopyranosyl donors carrying an azide group at the C4 position. A methodological study involving different anomeric leaving groups (acetate, phenylsulfoxide and ortho-hexynylbenzoate) showed that a sulfoxide donor in combination with trimethylsilyl triflate as the promoter led to the best yields.

Acceleration and deceleration factors on the hydrolysis reaction of 4,6-O-benzylidene acetal group

The benzylidene acetal group is one of the most important protecting groups not only in carbohydrate chemistry but also in general organic chemistry. In the case of 4,6-O-benzylidene glycosides, we previously found that the stereochemistry at 4-position altered the reaction rate constant for hydrolysis of benzylidene acetal group. However, a detail of the acceleration or deceleration factor was still unclear. In this work, the hydrolysis reaction of benzylidene acetal group was analyzed using the Arrhenius and Eyring plot to obtain individual parameters for glucosides (Glc), mannosides (Man), and galactosides (Gal). The Arrhenius and Eyring plot indicated that the pre-exponential factor (A) and ΔS? were critical for the smallest reaction rate constant of Gal among nonacetylated substrates. On the other hand, both Ea/ΔH? and A/ΔS? were influential for the smallest reaction rate constant of Gal among diacetylated substrates. All parameters obtained suggested that the rate constant for hydrolysis reaction was regulated by protonation and hydration steps along with solvation. The obtained parameters support wide use of benzylidene acetal group as orthogonal protection of cis- and trans-fused bicyclic systems through the fast hydrolysis of the trans-fused benzylidene acetal group.

Exploration of the Fluoride Reactivity of Aryltrifluoroborate on Selective Cleavage of Diphenylmethylsilyl Groups

The first known report on the fluoride catalytic reactivity of potassium aryltrifluoroborate is described. The fluoride reactivity of phenyltrifluoroborate was controlled by substituents on the trifluoroborate-attached benzene, such as the methoxy group a

A Direct Method for the Efficient Synthesis of Benzylidene Acetal at Room Temperature

For the first time, a metal-free direct method has been developed for the efficient synthesis of benzylidene acetal at room temperature using Dowex 50WX8 as a solid acid catalyst and Cl3CCN as a novel water scavenger. At room temperature, a wide variety of aryl and α,β-unsaturated aldehydes react readily with functionalized 1,2- and 1,3-diols to furnish the corresponding acetals in very good yields. Labile functional groups, like N-Boc, N-Cbz, -OTBDMS, -OBn, -N3 and acetonide are found to be stable under the reaction conditions. The versatility of this method is further demonstrated with carbohydrate substrates and optically active diols.

Conformational analysis of the disaccharide methyl a-d-mannopyranosyl-(1→3)-2-O-acetyl-β-D-manno-pyranoside monohydrate

The crystal structure of methyl β-d-mannopyranosyl-(1→3)-2-O-acetyl-β-d-mannopyranoside monohydrate, C15H26O12.H2O, (II), has been determined and the structural parameters for its constituent β-d-mannopyranosyl residue compared with those for methyl β-d-mannopyranoside. Mono-O-acetylation appears to promote the crystallization of (II), inferred from the difficulty in crystallizing methyl β-d-mannopyranosyl-(1→3)-β-d-mannopyranoside despite repeated attempts. The conformational properties of the O-acetyl side chain in (II) are similar to those observed in recent studies of peracetylated mannose-containing oligosaccharides, having a preferred geometry in which the C2—H2 bond eclipses the C O bond of the acetyl group. The C2—O2 bond in (II) elongates by ≈0.02 ? upon O-acetylation. The phi (φ) and psi () torsion angles that dictate the conformation of the internal O-glycosidic linkage in (II) are similar to those determined recently in aqueous solution by NMR spectroscopy for unacetylated (II) using the statistical program MA'AT, with a greater disparity found for (? = ≈16°) than for φ (? = ≈6°).

Synthesis and O-Glycosidic Linkage Conformational Analysis of 13C-Labeled Oligosaccharide Fragments of an Antifreeze Glycolipid

NMR studies of two 13C-labeled disaccharides and a tetrasaccharide were undertaken that comprise the backbone of a novel thermal hysteresis glycolipid containing a linear glycan sequence of alternating [βXylp-(1→4)-βManp-(1→4)]n dimers. Experimental trans-glycoside NMR J-couplings, parameterized equations obtained from density functional theory (DFT) calculations, and an in-house circular statistics package (MA'AT) were used to derive conformational models of linkage torsion angles φ and ψ in solution, which were compared to those obtained from molecular dynamics simulations. Modeling using different probability distribution functions showed that MA'AT models of φ in βMan(1→4)βXyl and βXyl(1→4)βMan linkages are very similar in the disaccharide building blocks, whereas MA'AT models of ψ differ. This pattern is conserved in the tetrasaccharide, showing that linkage context does not influence linkage geometry in this linear system. Good agreement was observed between the MA'AT and MD models of ψ with respect to mean values and circular standard deviations. Significant differences were observed for φ, indicating that revision of the force-field employed by GLYCAM is probably needed. Incorporation of the experimental models of φ and ψ into the backbone of an octasaccharide fragment leads to a helical amphipathic topography that may affect the thermal hysteresis properties of the glycolipid.

Binding of the Bacterial Adhesin FimH to Its Natural, Multivalent High-Mannose Type Glycan Targets

Multivalent carbohydrate-lectin interactions at host-pathogen interfaces play a crucial role in the establishment of infections. Although competitive antagonists that prevent pathogen adhesion are promising antimicrobial drugs, the molecular mechanisms underlying these complex adhesion processes are still poorly understood. Here, we characterize the interactions between the fimbrial adhesin FimH from uropathogenic Escherichia coli strains and its natural high-mannose type N-glycan binding epitopes on uroepithelial glycoproteins. Crystal structures and a detailed kinetic characterization of ligand-binding and dissociation revealed that the binding pocket of FimH evolved such that it recognizes the terminal α(1-2)-, α(1-3)-, and α(1-6)-linked mannosides of natural high-mannose type N-glycans with similar affinity. We demonstrate that the 2000-fold higher affinity of the domain-separated state of FimH compared to its domain-associated state is ligand-independent and consistent with a thermodynamic cycle in which ligand-binding shifts the association equilibrium between the FimH lectin and the FimH pilin domain. Moreover, we show that a single N-glycan can bind up to three molecules of FimH, albeit with negative cooperativity, so that a molar excess of accessible N-glycans over FimH on the cell surface favors monovalent FimH binding. Our data provide pivotal insights into the adhesion properties of uropathogenic Escherichia coli strains to their target receptors and a solid basis for the development of effective FimH antagonists.

Structure-Based Design of a Monosaccharide Ligand Targeting Galectin-8

Galectin-8 is a β-galactoside-recognising protein that has a role in the regulation of bone remodelling and is an emerging new target for tackling diseases with associated bone loss. We have designed and synthesised methyl 3-O-[1-carboxyethyl]-β-d-galacto

Stereoselective β-mannosylation via anomeric O-Alkylation: Concise synthesis of β-D-Xyl-(l→2)-β-D-Man-(1→4)-α-D-Glc-OMe, a trisaccharide oligomer of the hyriopsis schlegelii glycosphingolipid

Synthesis of ?-D-Xyl-(l→2)-?-D-Man-(1→4)-α-D-Glc-OMe (1), a trisaccharide oligomer of the Hyriopsis schlegelii glycosphingolipid is described. The synthesis involves a key ?-mannosylation via cesium carbonate-mediated anomeric O-alkylation for direct synt

From organocatalysed desilylations to high-yielding benzylidenations of electron-deficient benzaldehydes

A new type of organoprecatalyst (MeSCH2Cl/KI) for desilylation and benzylidenation reactions has been designed. Both reactions are user friendly and high yielding (71->99%) and have fast reaction rates. The desilylation of iodo silyl ethers was achieved with no sequential etherification side reactions like those seen for reactions when using TBAF. In the application of the catalytic system to a 6-TBDMS ether of a glucoside, glucoside benzylidenations using electron-deficient benzaldehydes were achieved in 87% yield compared with the previously reported yields of 69-77%. Altogether, 14 benzylidenation reactions were realised using silyloxy alcohols and electrondeficient benzaldehydes instead of their activated acetal forms. In terms of reaction rates and yields, the order of the benzylidenations is p-fluorobenzaldehyde > benzaldehyde > p-anisaldehyde, and a possible mechanism is discussed. These experiments have preliminarily differentiated this cost-effective catalytic system from the classic Lewis acids.