Elucidation of amino acid spin systems in proteins and determination of heteronuclear coupling constants by carbon-proton-proton three-dimensional NMR

1991 ◽  
Vol 92 (2) ◽  
pp. 434-438 ◽  
Author(s):  
Arthur S Edison ◽  
William M Westler ◽  
John L Markley
Keyword(s):  
Amino Acid ◽  
Three Dimensional ◽  
Spin Systems ◽  
Coupling Constants ◽  
Proton Proton ◽  
Heteronuclear Coupling

21,22-Disubstituted 18α,19βH-Ursane Derivatives with Oxabicyclooctane System in Ring E

1993 ◽  
Vol 58 (1) ◽  
pp. 173-190 ◽  
Author(s):  
Eva Klinotová ◽  
Jiří Klinot ◽  
Václav Křeček ◽  
Miloš Buděšínský ◽  
Bohumil Máca
Keyword(s):  
Spectral Data ◽  
Spin Systems ◽  
Coupling Constants ◽  
Complete Analysis ◽  
Nmr Spectrum ◽  
Proton Proton ◽  
H Nmr ◽  
Proton Coupling ◽  
C Nmr

Reaction of 3β-acetoxy-21,22-dioxo-18α,19βH-ursan-28,20β-olide (IIIa) and 20β,28-epoxy-21,22-dioxo-19α,19βH-ursan-3β-yl acetate (IIIb) with diazomethane afforded derivatives XII-XIV with spiroepoxide group in position 21 or 22, which were further converted into hydroxy derivatives XV and XVII. Ethylene ketals VIII-X were also prepared. In connection with the determination of position and configuration of the functional groups at C(21) and C(22), the 1H and 13C NMR spectral data of the prepared compounds are discussed. Complete analysis of two four-spin systems in the 1H NMR spectrum of bisethylenedioxy derivative Xb led to the proton-proton coupling constants from which the structure with two 1,4-dioxane rings condensed with ring E, and their conformation, was derived.

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.

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

Ultra high-resolution HSQC: application to the efficient and accurate measurement of heteronuclear coupling constants

2015 ◽  
Vol 51 (15) ◽  
pp. 3262-3265 ◽  
Author(s):  
Núria Marcó ◽  
André Fredi ◽  
Teodor Parella
Keyword(s):  
High Resolution ◽  
Coupling Constants ◽  
Rapid Acquisition ◽  
Enhanced Resolution ◽  
Nmr Techniques ◽  
Acquisition Strategy ◽  
Heteronuclear Coupling

A rapid acquisition strategy in terms of enhanced resolution per time unit for the simple and efficient determination of multiple coupling constants is proposed. The use of 13C spectral aliasing combined with pure shift NMR techniques allows accurate measurements of the magnitude and the sign from ultra high resolved 2D cross-peaks.

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