Heteronuclear coupling constants of hydroxyl protons in a water solution of oligosaccharides: trehalose and sucrose

1999 ◽  
Vol 320 (3-4) ◽  
pp. 267-272 ◽  
Author(s):  
Gyula Batta ◽  
Katalin E Kövér
Keyword(s):  
Water Solution ◽  
Coupling Constants ◽  
Hydroxyl Protons ◽  
Heteronuclear Coupling

Gradient-Enhanced Inverse-Detected NMR Techniquesfor Determination of 1H-15N Coupling Constants in 2,2-Dimethylpenta-3,4-dienal Derivatives

1997 ◽  
Vol 62 (11) ◽  
pp. 1747-1753 ◽  
Author(s):  
Radek Marek
Keyword(s):  
Double Bond ◽  
Chemical Shifts ◽  
Multiple Bond ◽  
Coupling Constants ◽  
Single Quantum ◽  
Nmr Techniques ◽  
Phase Sensitive ◽  
Heteronuclear Coupling

Determination of 15N chemical shifts and heteronuclear coupling constants of substituted 2,2-dimethylpenta-3,4-dienal hydrazones is presented. The chemical shifts were determined by gradient-enhanced inverse-detected NMR techniques and 1H-15N coupling constants were extracted from phase-sensitive gradient-enhanced single-quantum multiple bond correlation experiments. Stereospecific behaviour of the coupling constants 2J(1H,15N) and 1J(1H,13C) has been used to determine the configuration on a C=N double bond. The above-mentioned compounds exist predominantly as E isomers in deuteriochloroform.

Measurement of long-range heteronuclear coupling constants

1989 ◽  
Vol 85 (1) ◽  
pp. 111-131 ◽  
Author(s):  
Jeremy J Titman ◽  
David Neuhaus ◽  
James Keeler
Keyword(s):  
Long Range ◽  
Coupling Constants ◽  
Heteronuclear Coupling

scholarly journals CSSF-CLIP-HSQMBC: measurement of heteronuclear coupling constants in severely crowded spectral regions

RSC Advances ◽  
2019 ◽  
Vol 9 (62) ◽  
pp. 36082-36087 ◽  
Author(s):  
Aitor Moreno ◽  
Kine Østnes Hansen ◽  
Johan Isaksson
Keyword(s):  
Chemical Shift ◽  
Long Range ◽  
Program Development ◽  
Coupling Constants ◽  
Selective Filtration ◽  
User Friendly ◽  
Heteronuclear Coupling

A new pulse program development, a chemical shift selective filtration clean in-phase HSQMBC (CSSF-CLIP-HSQMBC), is presented for the user-friendly measurement of long-range heteronuclear coupling constants in severely crowded spectral regions.

Neue Untersuchung über Inhaltsstoffe aus Aloe-und Rhamnus-Arten, XV [1] Homonataloin A und B aus Aloe lateritia: Reindarstellung, Konstitutions-und Konfigurationsaufklärung der Diastereomeren / A New Investigation on Constituents of Aloe and Rhamnus Species, XV [1] Hom onataloins A and B from Aloe lateritia: Isolation, Structure and Configurational Determ ination of the Diastereomers

1991 ◽  
Vol 46 (3-4) ◽  
pp. 177-182 ◽  
Author(s):  
Hans-W. Rauwald ◽  
Deo-D. Niyonzima
Keyword(s):  
Chemical Shifts ◽  
Optical Rotation ◽  
Coupling Constants ◽  
Cd Spectra ◽  
Large Coupling ◽  
H Nmr ◽  
Leaf Exudate ◽  
Hydroxyl Protons ◽  
Nmr Signals ◽  
C Nmr

From the leaf exudate of Aloe lateritia ENGLER the C-glucosyl com pounds homonataloin, aloeresin A and aloesin (synon. aloeresin B) were isolated together with the anthraquinone nataloeem odin-8-methylether and spectroscopically identified. Hom onataloin, widely distributed in Aloe species, was separated into homonataloin A and B by combined TLC and DCCC. In their 1 D and 2D 1H NMR spectra only the shifts of the 2′-hydroxyl protons of both glucosyl residues differ significantly, indicative of 10 S (A) resp. 10 S (B) configurations. In both com pounds the anthrone is in β-position of the D-glucopyranosyl, as determined by the large coupling constants of the anomeric protons. The 13C NMR signals are unambiguously assigned by the use of DEPT, APT and gated-decoupling methods. Only the chemical shifts of C -11 and C -14 show significant differences between both diastereomers due to the adjacent 2′-sugar hydroxyls. The two homonataloins differ mostly in optical rotation and circulardichroism due to different configurations at C - 10 of the anthrone part. The absolute configurations of the diastereomers are determined by correlation of their CD spectra with the CD spectra of the structural analogues 7-hydroxyaloins A and B, which shows that hom onataloin A is the 10 S, 1′S-compound and that homonataloin B has 10 R, 1′S-configuration.

Assignment and conformational properties of the sugar-ring hydroxyl protons of the common nucleosides

1970 ◽  
Vol 48 (19) ◽  
pp. 3112-3115 ◽  
Author(s):  
D. B. Davies ◽  
S. S. Danyluk
Keyword(s):  
Solvent System ◽  
Coupling Constants ◽  
Magnetic Resonance Study ◽  
Gauche Conformation ◽  
Purine Base ◽  
Conformational Properties ◽  
Proton Magnetic Resonance Study ◽  
Sugar Ring ◽  
The Common ◽  
Hydroxyl Protons

A 60 MHz proton magnetic resonance study has been made of the hydroxyl protons of the ribose and deoxyribose rings for the common nucleosides dissolved in mixtures of dry DMSO-d6 and C6D6. Use of this solvent system permitted the detection and assignment of the exchange-free spin-coupled multiplets for the hydroxyl protons. The assignment was confirmed by spin-decoupling experiments.Based on the magnitudes of the observed coupling constants, it is concluded that the O—H5′, group is freely rotating around the C5′—O5′ bond. It is calculated that the O—H3′ bond favors a gauche conformation relative to the C3′—H3′ bond, consistent with the preferred conformation found in the solid state for the H3′—C3′—O3′—P bonds of the nucleoside 3′-phosphates. The conformation of the O—H2′ bond relative to the C2′—H2′- bond demonstrates no preference for the gauche rotamer. Such a rotamer might be expected if a hydrogen-bond between the 2′-OH and the purine base exists in this solvent system, as well as in aqueous solutions where such an interaction has been postulated as a stabilizing influence for ribosides.

scholarly journals Accurate determination of one-bond heteronuclear coupling constants with “pure shift” broadband proton-decoupled CLIP/CLAP-HSQC experiments

2014 ◽  
Vol 239 ◽  
pp. 130-138 ◽  
Author(s):  
István Timári ◽  
Lukas Kaltschnee ◽  
Andreas Kolmer ◽  
Ralph W. Adams ◽  
Mathias Nilsson ◽  
...  
Keyword(s):  
Accurate Determination ◽  
Coupling Constants ◽  
Heteronuclear Coupling

Survey of NMR experiments for the determination ofnJ(C,H) heteronuclear coupling constants in small molecules

2001 ◽  
Vol 39 (9) ◽  
pp. 499-530 ◽  
Author(s):  
Brian L. Marquez ◽  
William H. Gerwick ◽  
R. Thomas Williamson
Keyword(s):  
Small Molecules ◽  
Coupling Constants ◽  
Heteronuclear Coupling

PROTON MAGNETIC RESONANCE MEASUREMENTS OF FORMAMIDE

1960 ◽  
Vol 38 (5) ◽  
pp. 681-688 ◽  
Author(s):  
B. Sunners ◽  
L. H. Piette ◽  
W. G. Schneider
Keyword(s):  
Chemical Shifts ◽  
Water Solution ◽  
Proton Exchange ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Spin Interaction ◽  
Pure Liquid ◽  
Kcal Mole ◽  
Screening Constant ◽  
Spin Coupling Constants

The high-resolution proton resonance spectrum of formamide has been measured and analyzed. Quadrupole broadening of the resonance signals due to the N14 nucleus was eliminated by substitution of the isotopic nucleus N15. Twenty-four lines were resolved in the spectrum, which is consistent with restricted rotation about the C—N bond. The non-equivalence of the two protons in the N15H2 group is characterized by a smaller screening constant and a greater spin–spin interaction of the proton which is in the trans position relative to the carbonyl group. It is suggested this difference in the spin coupling of the two protons may be associated with different N—H bond lengths. Pronounced changes in the chemical shifts and spin-coupling constants result when formamide is dissolved in dilute solution in water and acetone. In water solution the relative magnitudes of the spin coupling of the two protons in the NH2 group is reversed from that observed in pure formamide and the coupling of the aldehyde proton to N15 varies by nearly 50%. Heating of formamide above room temperature causes rotation of the NH2 group as well as proton exchange between neighboring molecules. The two effects could be separated. From the observed changes in the proton spectra as a function of temperature the barrier hindering rotation (measured in a 10 mole% solution of formamide in acetone) was found to be 18 ± 3 kcal/mole. The activation energy for proton exchange in pure liquid formamide was found to be 10 ± 3 kcal/mole.

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