Study of rotation barriers inN,N-dimethylnicotinamide and quaternary salt derivatives by proton NMR. A correlation of rotation barriers ofN,N-dimethylamides with carbon-13 chemical shifts

1975 ◽  
Vol 7 (9) ◽  
pp. 422-425 ◽  
Author(s):  
J. A. Lepoivre ◽  
R. A. Dommisse ◽  
F. C. Alderweireldt
Keyword(s):  
Chemical Shifts ◽  
Quaternary Salt ◽  
Proton Nmr

Parameters for the Calculation of Proton NMR Chemical Shifts of Oligoribonucleotides

1985 ◽  
Vol 2 (4) ◽  
pp. 693-707 ◽  
Author(s):  
Russell A. Bell ◽  
Jeremy R. Everett ◽  
Donald W. Hughes ◽  
Jan M. Coddington ◽  
Dirk Alkema ◽  
...  
Keyword(s):  
Chemical Shifts ◽  
Proton Nmr ◽  
Nmr Chemical Shifts

Chemical shift correlated two-dimensional nmr spectroscopy and its application to solving the proton nmr spectra of oligoribonucleotides

1980 ◽  
Vol 58 (18) ◽  
pp. 1947-1956 ◽  
Author(s):  
Alex D. Bain ◽  
Russell A. Bell ◽  
Jeremy R. Everett ◽  
Donald W. Hughes
Keyword(s):  
Nmr Spectroscopy ◽  
Chemical Shift ◽  
Nmr Spectra ◽  
Pulse Sequence ◽  
Chemical Shifts ◽  
Proton Nmr ◽  
Two Dimensional

An alternative two-dimensional nmr pulse sequence, (90°–t1/2–90°–t1/2–FID),correlates the chemical shifts of coupled nuclei. The application of this technique to the solution of the complicated proton nmr spectra of oligoribonucleotides is discussed.

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.

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