1H-NMR spectra and nuclear Overhauser effect in E and Z isomers of 3-substituted 3-aminoacrylonitriles

1975 ◽  
Vol 40 (11) ◽  
pp. 3476-3490 ◽  
Author(s):  
J. Dědina ◽  
J. Kuthan ◽  
J. Paleček ◽  
J. Schraml
Keyword(s):  
1H Nmr ◽  
Nmr Spectra ◽  
Nuclear Overhauser Effect ◽  
1H Nmr Spectra ◽  
Overhauser Effect ◽  
E And Z Isomers ◽  
Nuclear Overhauser

1H NMR studies of [N-MeAib1, Tyr(Me)4]ANGII and [N-MeAib1, Tyr(Me)4, Ile8]ANGII in dimethylsulfoxide by nuclear Overhauser effect (NOE) enhancement spectroscopy: cis-trans Isomerism of the His-Pro bond

1990 ◽  
Vol 55 (4) ◽  
pp. 1106-1111 ◽  
Author(s):  
John Matsoukas ◽  
Paul Cordopatis ◽  
Raghav Yamdagni ◽  
Graham J. Moore
Keyword(s):  
1H Nmr ◽  
Nuclear Overhauser Effect ◽  
Nmr Studies ◽  
Restricted Rotation ◽  
Overhauser Effect ◽  
Major Isomer ◽  
Conformational Properties ◽  
Nuclear Overhauser

The conformational properties of the Sarmesin analogues [N-MeAib1, Tyr(Me)4]ANGII and [N-MeAib1, Tyr(Me)4, Ile8]ANGII in hexadeutero-dimethysulfoxide were investigated by Nuclear Overhauser Effect (NOE) Enhancement Studies. Cis-trans isomers (ratio 1 : 6) due to restricted rotation of the His-Pro bond were observed. Interresidue interactions between the His Cα proton and the two Pro Cδ protons revealed that the major isomer was the trans.

Nuclear Overhauser Effect (NOE) Enhancement of11B NMR Spectra of Borane Adducts in the Solid State

2006 ◽  
Vol 128 (21) ◽  
pp. 6782-6783 ◽  
Author(s):  
Sharon E. Ashbrook ◽  
Nicholas G. Dowell ◽  
Ivan Prokes ◽  
Stephen Wimperis
Keyword(s):  
Solid State ◽  
Nmr Spectra ◽  
Nuclear Overhauser Effect ◽  
Overhauser Effect ◽  
Nuclear Overhauser

Isotopic-label-directed observation of the nuclear Overhauser effect in poorly resolved proton NMR spectra

1985 ◽  
Vol 107 (3) ◽  
pp. 711-712 ◽  
Author(s):  
R. H. Griffey ◽  
M. A. Jarema ◽  
S. Kunz ◽  
P. R. Rosevear ◽  
A. G. Redfield
Keyword(s):  
Nmr Spectra ◽  
Nuclear Overhauser Effect ◽  
Proton Nmr ◽  
Isotopic Label ◽  
Overhauser Effect ◽  
Nuclear Overhauser

scholarly journals Comparison of Regular, Pure Shift, and Fast 2D NMR Experiments for Determination of the Geographical Origin of Walnuts

Metabolites ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 39
Author(s):  
Stephanie Watermann ◽  
Caroline Schmitt ◽  
Tobias Schneider ◽  
Thomas Hackl
Keyword(s):  
Statistical Analysis ◽  
1H Nmr ◽  
Nmr Spectra ◽  
Geographical Origin ◽  
Nuclear Overhauser Effect ◽  
Juglans Regia ◽  
2D Nmr ◽  
Support Vector ◽  
Nuclear Overhauser ◽  
The One

1H NMR spectroscopy, in combination with chemometric methods, was used to analyze the methanol/acetonitrile (1:1) extract of walnut (Juglans Regia L.) regarding the geographical origin of 128 authentic samples from different countries (France, Germany, China) and harvest years (2016–2019). Due to the large number of different metabolites within the acetonitrile/methanol extract, the one-dimensional (1D) 1H NOESY (nuclear Overhauser effect spectroscopy) spectra suffer from strongly overlapping signals. The identification of specific metabolites and statistical analysis are complicated. The use of pure shift 1H NMR spectra such as PSYCHE (pure shift yielded by chirp excitation) or two-dimensional ASAP-HSQC (acceleration by sharing adjacent polarization-heteronuclear single quantum correlation) spectra for multivariate analysis to determine the geographical origin of foods may be a promising method. Different types of NMR spectra (1D 1H NOESY, PSYCHE, and ASAP-HSQC) were acquired for each of the 128 walnut samples and the results of the statistical analysis were compared. A support vector machine classifier was applied for differentiation of samples from Germany/China, France/Germany, and France/China. The models obtained by conduction of a repeated nested cross-validation showed accuracies from 58.9% (±1.3%) to 95.9% (±0.8%). The potential of the 1H-13C HSQC as a 2D NMR experiment for metabolomics studies was shown.

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