Simultaneous determination of the magnitude and the sign of multiple heteronuclear coupling constants in 19  F or 31 P-containing compounds

2015 ◽  
Vol 53 (6) ◽  
pp. 427-432 ◽  
Author(s):  
Josep Saurí ◽  
Pau Nolis ◽  
Teodor Parella
Keyword(s):  
Simultaneous Determination ◽  
Coupling Constants ◽  
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.

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

A Rapid and Accurate 1HNMR Method for the Identification and Quantification of Major Constituents in Qishen Yiqi Dripping Pills

2020 ◽  
Author(s):  
Qingling Xie ◽  
Limin Gong ◽  
Feibing Huang ◽  
Mengru Cao ◽  
Yongbei Liu ◽  
...  
Keyword(s):  
Simultaneous Determination ◽  
Chemical Shifts ◽  
Salvia Miltiorrhiza ◽  
Proton Nmr ◽  
Herbal Medicines ◽  
Panax Notoginseng ◽  
Hplc Method ◽  
Coupling Constants ◽  
Identification And Quantification

Abstract Background Qishen Yiqi dripping pills (QSYQ), composed of four herbal medicines—Salvia miltiorrhiza, Astragalus membranaceus, Panax notoginseng, and Dalbergiaodorifera—are widely used to treat ischemic cerebrovascular and hemorrhagic cerebrovascular conditions. Objective In this study, a rapid and accurate proton NMR (1HNMR) spectroscopy method was established to control the quality of QSYQ and ensure their clinical efficacy. Method Firstly, different types of metabolites were identified based on the proton signal peaks of chemical shifts, coupling constants, and related information provided through two-dimensional NMR spectroscopy. Secondly, a quantitative 1HNMR method was established for the simultaneous determination of major constituents in QSYQ samples. In addition, an HPLC method was performed to verify the results obtained by the quantitative proton NMR (qHNMR)  method. Results In the present study, 26 metabolites were identified in the 1HNMR spectra of QSYQ. In addition, a rapid and accruate qHNMR method was established for the simultaneous determination of protocatechualdehyde, rosmarinic acid, danshensu, calycosin-7-O-β-D-glucoside, and ononin in ten batches of QSYQ samples for the first time. Moreover, the proposed qHNMR method and HPLC method were compared using Bland-Altman and plots Passing-Bablok regression, indicating no significant differences and a strong correlation between the two analytical methods. Conclusions This method is an important tool for the identification and quantification of major constituents in QSYQ. Highlights Compared with traditional HPLC, the established qHNMR method has the advantages of simple sample preparation, short analysis time, and non-destructive analysis.

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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