Observation of hydroxyl protons of sucrose in aqueous solution: no evidence for persistent intramolecular hydrogen bonds

Adams, Bruce R.; Lerner, Laura

doi:10.1021/ja00038a055

Cited by 113 publications

(93 citation statements)

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“…[46][47][48] Till the recent year, 9 longrange heteronuclear couplings involving the exchangeable OHgroups, 3 J C(i21)OHi and 3 J C(i11)OHi , have been mostly used qualitatively to describe the conformational preference of OHgroups. 19,24,49 In this study for quantitative assessment of rotamer populations, a Karplus-type equation with Tvaroska parameters proposed for the CÀ ÀOÀ ÀCÀ ÀH interglycosidic segment [50][51][52] was used for the interpretation of heteronuclear vicinal 3 J C,OH couplings. First, the probability of two rotamers, in which the relevant atoms (proton-proton and proton-carbon) are in antiperiplanar arrangement were estimated from the vicinal homonuclear and heteronuclear coupling constants.…”

Section: Resultsmentioning

confidence: 99%

“…Although hydroxyl exchange rates can be slowed by supercooling the aqueous solution, 17 or by using organic solvents (DMSO-d 6 , acetone-d 6 , CDCl 3 ) 18 or cosolvents, 19 making the measurement of the conformationally relevant three-bond couplings 20 feasible, however, till the recent year, 9 appropriate Karplus equation relating the heteronuclear vicinal coupling constant 3 J C,OH to CÀ ÀO torsion angle has not been available. Although there are other NMR probes to study the involvement of OH groups in hydrogen bonds, such as determining the temperature and/or solvent dependence of OH-chemical shifts [21][22][23][24][25][26][27][28][29] or measuring the isotope effects.…”

Section: Introductionmentioning

confidence: 99%

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Combined NMR three‐bond scalar coupling measurements and QM calculations to calculate OH‐rotamer equilibrium of polyalcohols

et al. 2008

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A combined but independently applied NMR and QM procedure has been used to investigate the conformational properties of the exchangeable hydroxyl protons of polyalcohols. In this study, to demonstrate the applicability of such a strategy, we investigated a simple monosaccharide, i.e. alpha- and beta-anomers of a D-glucopyranoside derivative. The redundant set of experimental vicinal homonuclear and heteronuclear scalar couplings involving the OH-protons obtained for both anomers of our model compound were simultaneously analyzed to yield the preferred OH-rotamer populations and moreover to parametrize a new Karplus-type equation for (3)J(C(i-1)OH(i)) coupling. The populations of the lowest energy conformers and the conformational-averaged coupling constants were independently calculated using the QM approach in both vacuum and chloroform. The similarity of the estimated rotamer populations obtained by two very different techniques and the similarity of the experimental and calculated coupling constants suggest that these approaches can be used in conjunction and in a fully integrated way to determine a more accurate atomic level description of molecular conformers.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Combined NMR three‐bond scalar coupling measurements and QM calculations to calculate OH‐rotamer equilibrium of polyalcohols

et al. 2008

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“…It is known that DMSO as solvent slows down the chemical exchange among hydroxy protons and enhances the formation of H bonds, [21] which could be www.eurjoc.org disrupted by a protic solvent such as water. [22] In fact, when this solvent mixture was used, it was possible to detect the exchangeable protons in a wider range of temperature than with acetone, from 273 to 253 K, making possible to determine some temperature coefficients ( Table 2). The temperature coefficients (k), which are known to be dependent on the solvent used, [21] had intermediate values and did not allow to detect definitely those hydroxy groups engaged in a persistent hydrogen bond.…”

Section: Vsg Gpi By Nmrmentioning

confidence: 99%

“…A 3 mm NMR tube (300 μL) was previously soaked in a 50 mm solution of phosphate buffer (pH = 7) to minimize adsorption of impurities from glassware. [22] Temperature coefficient experiments were recorded at 298, 293, 273, 268, 263, 258, and 253 K. Water suppression was performed by inserting a watergate module [45] previous to the acquisition. Gradient-enhanced or selected versions of TOCSY, ROESY, NOESY experiments were used.…”

Section: Nmrmentioning

confidence: 99%

Conformational Study of GPI Anchors: the Common Oligosaccharide GPI Anchor Backbone

Chevalier¹,

López-Prados²,

Pérez³

et al. 2005

Eur J Org Chem

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The solution three‐dimensional structure of pseudopentasaccharide 6, which constitutes the product from the GPI‐PLD cleavage of a GPI anchor, has been studied using a protocol which involves a systematic search of the conformational space around the glycosidic linkages, a thorough molecular dynamics study with explicit water molecules and a full NMR analysis study of intramolecular hydrogen bonding in solution. The results indicate that 6 exists in an extended conformation with a considerable flexibility compatible with a hinge‐like conformational motion. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

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“…For studies in aqueous solution, this complication can be overcome by employing mixed solvents 44,45 or by supercooling appropriately prepared aqueous solutions free of trace exchange catalysts. 46 Most studies, however, employ a Lewis basic solvent, such as DMSO, to slow the rate of exchange, thus providing sharp hydroxyl groups as spectral landmarks.…”

Section: On the Prospect Of Using Ohð ð ðOh Couplings In Structural Smentioning

confidence: 99%

Density functional theory studies of transannular1H?1HJ-coupling in half-cage alcohols and rigid 1,3- and 1,4-diols: conformational dependencies and implications for intramolecular hydrogen bond detection in carbohydrates

Barfield¹,

Bergset²,

O’Leary³

2001

Magn. Reson. Chem.

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Density functional theory (DFT) methods were used to investigate the conformational dependence of transannular H-H coupling constants in half-cage alcohols and cage diols. Finite perturbation theory (FPT) was used to obtain the Fermi contact (FC) contributions to scalar coupling constants in three halfcage alcohols and the OH· · ·OH coupling between hydroxyl groups sharing 1,4-and 1,3-intramolecular hydrogen bonds. Transannular CH· · ·OH coupling constants in the half-cage alcohols (inner OH) were obtained as a function of the dihedral angle defining the OH orientation. In comparison with the parent compound, chlorine substituents substantially modify the conformational dependence of the transannular H-H coupling and lead to observable coupling in the hexachloro compound. This is an unusual case, wherein the conformationally averaged coupling constants are quite different than those for the minimumenergy conformations. A −1.0 Hz scalar coupling is predicted between the very crowded protons in the half-cage acetate (outer OAc) in comparison with the experimental magnitude <1 Hz. In model 1,4-and 1,3-diols the coupling constants were obtained as functions of the analogous dihedral angles. The primary effects of hydrogen bonding are the stabilization of conformations in which the positive and negative contributions effectively cancel, thereby leading to small, observed values (e.g. ≤0.3 Hz). The DFT/FPT data for transannular coupling constants are consistent with a sum-over-states analysis for the direct mechanisms involving the two bonds containing the coupled nuclei rather than indirect mechanisms associated with oxygen lone pairs. Discussed here are the prospects of using OH· · ·OH scalar coupling for structural studies of carbohydrates.

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Observation of hydroxyl protons of sucrose in aqueous solution: no evidence for persistent intramolecular hydrogen bonds

Cited by 113 publications

References 0 publications

Combined NMR three‐bond scalar coupling measurements and QM calculations to calculate OH‐rotamer equilibrium of polyalcohols

Combined NMR three‐bond scalar coupling measurements and QM calculations to calculate OH‐rotamer equilibrium of polyalcohols

Conformational Study of GPI Anchors: the Common Oligosaccharide GPI Anchor Backbone

Density functional theory studies of transannular1H?1HJ-coupling in half-cage alcohols and rigid 1,3- and 1,4-diols: conformational dependencies and implications for intramolecular hydrogen bond detection in carbohydrates

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