A Synthetic Lectin Analog for Biomimetic Disaccharide Recognition

Science ◽  
2007 ◽  
Vol 318 (5850) ◽  
pp. 619-622 ◽  
Author(s):  
Yann Ferrand ◽  
Matthew P. Crump ◽  
Anthony P. Davis
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Carbohydrate Binding ◽  
Hydroxyl Groups ◽  
Complete Suppression ◽  
Induced Circular Dichroism ◽  
Synthetic Receptor ◽  
Self Consistent ◽  
Carbohydrate Binding Proteins ◽  
And Calorimetry

Carbohydrate recognition is biologically important but intrinsically challenging, for both nature and host-guest chemists. Saccharides are complex, subtly variable, and camouflaged by hydroxyl groups that hinder discrimination between substrate and water. We have developed a rational strategy for the biomimetic recognition of carbohydrates with all-equatorial stereochemistry (β-glucose, analogs, and homologs) and have now applied it to disaccharides such as cellobiose. Our synthetic receptor showed good affinities, not unlike those of some lectins (carbohydrate-binding proteins). Binding was demonstrated by nuclear magnetic resonance, induced circular dichroism, fluorescence spectroscopy, and calorimetry, all methods giving self-consistent results. Selectivity for the target substrates was exceptional; minor changes to disaccharide structure (for instance, cellobiose to lactose) caused almost complete suppression of complex formation.

Substitutional and solvation effects on conformational equilibria. Effects on the interaction between opposing axial oxygen atoms

1969 ◽  
Vol 47 (23) ◽  
pp. 4441-4446 ◽  
Author(s):  
R. U. Lemieux ◽  
A. A. Pavia
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Hydrogen Bonding ◽  
Magnetic Resonance ◽  
Hydroxyl Groups ◽  
Evidence Based ◽  
Electrostatic Repulsion ◽  
Hydrogen Bridge ◽  
Conformational Equilibria ◽  
Free Hydroxyl ◽  
Oxygen Atoms

Evidence based both on nuclear magnetic resonance and rotation data primarily obtained from methyl 3-deoxy-β-L-erythro-pentopyranoside and a number of its derivatives is interpreted to show that the electrostatic repulsion between the oxygen atoms at the 2 and 4 positions is substantially less when these oxygens are linked to acyl groups than when in the form of either methyl ethers or as hydroxyl groups hydrogen bonded to solvent. Also, experimental evidence is presented which requires the hydrogen bridge between two axially disposed hydroxyl groups to be substantially strengthened by hydrogen bonding of the free hydroxyl by solvent.

A Comparison of the Conformations of Uridine, β-Pseudouridine, and Dihydrouridine in Dimethyl Sulfoxide and Water. A 1H Nuclear Magnetic Resonance Study

1973 ◽  
Vol 51 (6) ◽  
pp. 833-838 ◽  
Author(s):  
Roxanne Deslauriers ◽  
Ian C. P. Smith
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Dimethyl Sulfoxide ◽  
Nuclear Magnetic Resonance Study ◽  
Hydroxyl Groups ◽  
Deuterated Water ◽  
Magnetic Resonance Study ◽  
1H Nuclear Magnetic Resonance ◽  
Sugar Ring ◽  
Hydroxyl Protons

The 1H n.m.r. spectra of the nucleosides uridine (U), dihydrouridine (D), and β-pseudouridine (β-ψ) in deuterated dimethyl sulfoxide (DMSO-d6) have been analyzed and the results compared with those obtained from analyses of spectra taken in deuterated water (D2O). The conformations of the ribose rings in DMSO-d6 and D2O solutions are similar. The conformation about the exocyclic C4′—C5′ bond shows a greater preference for the gauche–gauche rotamer in DOMO-d6 than in D2O. No changes in the sugar–base torsion angle were detectable in the spectra taken with the two solvents. The resonances of the sugar ring hydroxyl protons were assigned and the spin–spin couplings measured. In the three nucleosides studied the hydroxyl groups are rotating rapidly with only slight preferences for the particular rotamers. When preferences are manifest, they are for the gauche rotamers at 2′ and 3′, and the symmetrical gauche–gauche rotamer at 5′.

Development of sustainable resource based poly(urethane-etheramide)/Fe2O3 nanocomposite as anticorrosive coating materials

2015 ◽  
Vol 35 (9) ◽  
pp. 905-916 ◽  
Author(s):  
Mohammed Rafi Shaik ◽  
Manawwer Alam ◽  
Naser M. Alandis
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Tap Water ◽  
Linseed Oil ◽  
Proton Nuclear Magnetic Resonance ◽  
Nanocomposite Coatings ◽  
Hydroxyl Groups ◽  
Condensation Polymerization ◽  
Standard Methods ◽  
Nuclear Magnetic

Abstract Linseed polyetheramide (LPEtA) resin was synthesized by the condensation polymerization of N-N-bis (2-hydroxyethyl) linseed oil fatty amide (HELA) with pyrogallol. The residual hydroxyl groups of LPEtA resin were further modified with isophorone diisocyanate (IPDI) to obtain linseed poly(urethane-etheramide) (ULPEtA) via addition polymerization. ULPEtA was modified with iron oxide nanoparticles in different weight percent (0.1 wt%, 0.2 wt%, 0.3 wt% and 0.4 wt%) producing ULPEtA/Fe2O3 nanocomposite. Spectroscopic characterization of HELA, LPEtA and ULPEtA was carried out by using Fourier transform infrared (FT-IR), proton nuclear magnetic resonance (1H-NMR) and carbon nuclear magnetic resonance (13C-NMR) techniques. Physicochemical and physico-mechanical properties of LPEtA and ULPEtA were carried out by using standard methods. Thermal stability and anticorrosion performance were assessed by thermogravimetric analysis/differential scanning calorimetry (TGA/DSC) and potentiodynamic polarization. The corrosion behavior of ULPEtA/Fe2O3 nanocomposite coatings on mild steel was investigated in different corrosive environments (3.5 wt% HCl, 5.0 wt% NaCl, 3.5 wt% NaOH, and tap water) at room temperature. Surface morphology study was performed through scanning electron microscopy (SEM) and energy dispersive X-ray (EDX). Coating properties such as gloss, scratch hardness, flexibility and impact resistance were evaluated using standard methods. The results of this study showed that ULPEtA/Fe2O3 nanocomposite coatings exhibit good physico-mechanical, anticorrosive properties and can be safely used up to 220°C.

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