1 H NMR spectra. Part 29§: proton chemical shifts and couplings in esters-the conformational analysis of methyl γ-butyrolactones

2012 ◽  
Vol 51 (1) ◽  
pp. 9-15 ◽  
Author(s):  
Raymond J. Abraham ◽  
Paul Leonard
Keyword(s):  
Conformational Analysis ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
H Nmr ◽  
Proton Chemical Shifts

Preparation and properties of β-ketosulphones of 5-nitrofuran series. Study of transfer of electronic effects through sulphone group

1982 ◽  
Vol 47 (2) ◽  
pp. 617-621 ◽  
Author(s):  
Dana Polakovičová ◽  
Adolf Jurášek ◽  
Vladimír Kvasnička
Keyword(s):  
Linear Dependence ◽  
Quantum Chemical ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Electronic Effects ◽  
H Nmr ◽  
Physical Measurements ◽  
Hammett Constants ◽  
Series Study ◽  
Proton Chemical Shifts

A series of 2-(5-nitro-2-furyl)-2-oxoethylarylsulphones have been synthesized by reaction of 5-nitro-2-bromoacetylfuran with sodium p-X-benzenesulphinates (where X = H, CH3, OCH3, CH3CONH, NH2, N(CH3)2, Cl, NO2) and used for a study of transfer of electronic effects of the substituent through SO2 group. The found linear dependence between the proton chemical shifts in 1H NMR spectra (and pKa values of the CH2 group) and the Hammett constants of the substituents proves the existence of the transfer through SO2 group. The results of physical measurements were compared with the data obtained by quantum-chemical calculations using the EHT method.

scholarly journals 13C and 1H NMR Spectra of Synthetic (25R)-5α-Spirostanes

1999 ◽  
Vol 23 (1) ◽  
pp. 48-49
Author(s):  
Martín A. Iglesias Arteaga ◽  
Carlos S. Pérez Martinez ◽  
Roxana Pérez Gil ◽  
Francisco Coll Manchado
Keyword(s):  
1H Nmr ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
1H Nmr Spectra ◽  
H Nmr ◽  
C 23 ◽  
Main Effects ◽  
Nmr Signals

The assignment of 13C and 1H NMR signals of synthetic (25 R)-5α-spirostanes is presented; the main effects on chemical shifts due to substitution at C-23 are briefly discussed.

Conformational analysis of a seven-membered ring azasugar, (3R,4R,6S)-trihydroxyazepane: Comparison of GIAO calculation and experimental NMR spectra on 13C chemical shifts

2012 ◽  
Vol 1018 ◽  
pp. 64-71 ◽  
Author(s):  
Pao-Ling Yeh ◽  
Chin-Kuen Tai ◽  
Tzenge-Lien Shih ◽  
Hui-Ling Hsiao ◽  
Bo-Cheng Wang
Keyword(s):  
Conformational Analysis ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Membered Ring ◽  
13C Chemical Shifts

Chemical shifts of charge-transfer complexes and Buckingham equation

1990 ◽  
Vol 55 (9) ◽  
pp. 2131-2137
Author(s):  
Mahboob Mohammad ◽  
Ather Yaseen Khan ◽  
Tariq Mahmood ◽  
Ismat Fatima ◽  
Riffat Shaheen ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Nmr Spectra ◽  
Charge Transfer Complex ◽  
Chemical Shifts ◽  
Charge Transfer Complexes ◽  
Aprotic Solvents ◽  
Reaction Field ◽  
H Nmr ◽  
Spherical Cavities ◽  
Dipolar Aprotic Solvents

The 1H NMR spectra of the charge-transfer complex of 1-ethyl-4-methoxycarbonylpyridinium iodide have been recorded in various dipolar aprotic solvents. An attempt is made to interpret the chemical shifts in terms of Buckingham's reaction field equation for spherical cavities. A linear dependence has been found between the δ(2,6) values and the square of dielectric function for a spherical cavity, which confirms the validity of the Buckingham equation for this class of compounds.

Analyses of the complex proton NMR spectra: Determination of anisotropic proton chemical shifts of oriented molecules by a two dimensional experiment

2007 ◽  
Vol 185 (2) ◽  
pp. 240-246 ◽  
Author(s):  
Raghav G. Mavinkurve ◽  
H.S. Vinay Deepak ◽  
K.V. Ramanathan ◽  
N. Suryaprakash
Keyword(s):  
Nmr Spectra ◽  
Chemical Shifts ◽  
Proton Nmr ◽  
Two Dimensional ◽  
Oriented Molecules ◽  
Proton Chemical Shifts

13C-NMR-Spektroskopie an polycyclischen Aromaten, II. Die 13C-NMR-Spektren von 1- und 2-Fluornaphthalin. Überprüfung der Signalzuordnung und Untersuchung der Substituenteneffekte auf die chemischen Verschiebungen / 13C NMR Spectroscopy of Polycyclic Aromatics, II. The 13C NMR Spectra of 1- and 2-Fluoronaphthalene. Reexamination of Signal Assignments and Investigation of Substituent Effects on Chemical Shifts

1975 ◽  
Vol 30 (9-10) ◽  
pp. 788-793 ◽  
Author(s):  
Ludger Ernst
Keyword(s):  
13C Nmr ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Double Resonance ◽  
Substituent Effects ◽  
13C Nmr Spectroscopy ◽  
Polycyclic Aromatics ◽  
H Nmr ◽  
Iterative Analysis ◽  
C Nmr

During a reinvestigation of the 13C NMR spectra of 1-fluoronaphthalene (1) and of 2-fluoronaphthalene (2) at 20 and 25.16 MHz, uncertainties that existed in the literature about signal assignments for 1 could be cleared. In the spectral analyses for 2 given so far, five out of ten signals were incorrectly assigned. The corrected assignment is supported by extensive 13C{1H} double resonance experiments, by recording of proton-coupled 13C and 13C{19F} spectra and by off-resonance 13C{1H} noise-decoupling. The results show a strong + M-effect of the fluorine substituents on 13C chemical shifts similar to the effects of OH and OCH3 groups. 1H NMR spectra of 1 and 2 could be partially assigned by decoupling of the 19F resonances and by iterative analysis.

Conformation of ring A in triterpenoid and 4,4-dimethylsteroid 3-ketones. Chemical shifts of methyl protons and lanthanide and benzene induced shifts

1990 ◽  
Vol 55 (3) ◽  
pp. 766-781 ◽  
Author(s):  
Jiří Klinot ◽  
Miloš Buděšínský ◽  
Jarmil Světlý
Keyword(s):  
Nmr Spectra ◽  
Chemical Shifts ◽  
Methyl Groups ◽  
Pentacyclic Triterpene ◽  
H Nmr ◽  
Lanthanide Induced Shifts ◽  
Physical Data

Chemical shifts of signals due to methyl groups in position 10β (in CDCl3) and 4α and 4β (in C6D6) in 1H NMR spectra of pentacyclic triterpene 3-oxo derivatives (V, VIII, IX, and XII) are suitable for estimation of chair-boat equilibrium in the ring A. Benzene and lanthanide induced shifts of 4α and 4β-methyl protons were also used for this purpose. The results obtained with 2α-methyl-3-ketones (III, X) and 2β-methyl-3-ketones (IV, XI) as the respective chair and boat models agree well with those derived from other physical data (about 40% boat). The same methods were applied to 4,4-dimethylsteroid 3-ketones XV-XVII.

Anisotropic effect of the nitrate anion—manifestation of diamagnetic proton chemical shifts in the 1H NMR spectra of NO3− coordinated complexes

Tetrahedron ◽  
2008 ◽  
Vol 64 (22) ◽  
pp. 5044-5050 ◽  
Author(s):  
Erich Kleinpeter ◽  
Andreas Koch ◽  
Himansu S. Sahoo ◽  
Dillip Kumar Chand
Keyword(s):  
1H Nmr ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
1H Nmr Spectra ◽  
Nitrate Anion ◽  
Anisotropic Effect ◽  
Proton Chemical Shifts
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