The stereochemistry of some 7-hydroxyindene dimers: applications of 1H nuclear magnetic resonance relaxation pathway analysis

1985 ◽  
Vol 63 (8) ◽  
pp. 2332-2338 ◽  
Author(s):  
Walter J. Chazin ◽  
Lawrence D. Colebrook ◽  
Brian R. Davis ◽  
I. Ross N. McCormick ◽  
Stephen J. Johnson
Keyword(s):  
Nuclear Overhauser Effect ◽  
Chemical Shifts ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Relaxation Rates ◽  
Difference Spectra ◽  
Spin Lattice ◽  
Relative Stereochemistry ◽  
Effect Difference ◽  
Nuclear Overhauser

1H spin-lattice relaxation rates and nuclear Overhauser effect difference spectra have been measured (at 400 MHz) for six dimers derived from methyl-substituted 7-hydroxyindenes. Used in combination, these measurements identify the relaxation pathways available to all of the protons in the molecules. Analysis of these pathways has permitted assignment of all chemical shifts, and identification of the relative stereochemistry at all chiral centres.

Relaxation pathway analysis by 1H spin-lattice relaxation and nuclear Overhauser effect difference measurements. Application to a reassignment of the 1H nmr spectrum of strychnine and to the determination of the structure and stereochemistry of some strychnine sulfonic acids

1983 ◽  
Vol 61 (8) ◽  
pp. 1749-1755 ◽  
Author(s):  
Walter J. Chazin ◽  
Lawrence D. Colebrok ◽  
John T. Edward
Keyword(s):  
Pathway Analysis ◽  
Nuclear Overhauser Effect ◽  
Lattice Relaxation ◽  
Coupling Constants ◽  
Spin Lattice Relaxation ◽  
Sulfonic Acids ◽  
Spin Lattice ◽  
Overhauser Effect ◽  
Effect Difference ◽  
Nuclear Overhauser

The 1H relaxation pathway analysis of strychnine and some strychnine sulfonic acids has been carried out by spin-lattice relaxation and nuclear Overhauser effect difference measurements. Some previously reported 1H chemical shifts and coupling constants for strychnine are shown to be in error. New assignments for positions 15, 17, 18, and 20 have been made. Proposed sites of substitution of the sulfonic acids have been verified, and the previously undetermined stereochemistry of one of the acids has been established.

Applications of the intermolecular nuclear Overhauser effect. I. Determination of differential solvent effects: the hydration of pyridine

1983 ◽  
Vol 36 (3) ◽  
pp. 493 ◽  
Author(s):  
GR Smith ◽  
B Ternai
Keyword(s):  
Nuclear Overhauser Effect ◽  
Water System ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Alternative Methods ◽  
Relaxation Rates ◽  
Overhauser Effect ◽  
Nuclear Overhauser ◽  
Intermolecular Relaxation

The intermolecular relaxation rates of the pyridine-water system have been obtained by the measurement of the total spin lattice relaxation rate and the intermolecular nuclear Overhauser effect between pyridine and water, for each pyridine proton. The advantages of this method for the determination of the intermolecular relaxation rates are discussed, and the method is compared with alternative methods. The results indicate that there is a varying degree of hydration about the pyridine molecule, with the nitrogen being the preferred site of water interaction. It is necessary to interpret the results in terms of solute-solute as well as solute-solvent interactions. A model is proposed which takes account of both types of interaction, and is considered in terms of previously proposed models of pyridine-water interactions.

The conformational equilibrium in [13C-1-methyl]-cis-1,4-dimethylcyclohexane

1980 ◽  
Vol 58 (23) ◽  
pp. 2709-2713 ◽  
Author(s):  
Harold Booth ◽  
Jeremy Ramsey Everett
Keyword(s):  
Conformational Equilibrium ◽  
Chemical Shifts ◽  
Relaxation Times ◽  
Lattice Relaxation ◽  
Coupling Constants ◽  
Spin Lattice Relaxation ◽  
Spin Lattice ◽  
Nuclear Overhauser ◽  
In Cis ◽  
C Nmr

The conformational equilibrium in [13C-1-methyl]-cis-1,4-dimethylcyclohexane has been assessed by (a) direct integration of signals due to equatorial and axial methyl carbons in the 13C nmr spectrum at 172 K and (b) by measurement of the 13C chemical shifts of C-1 and C-4 in the spectrum at 300 K. It is concluded that a 13C isotope effect on the position of the degenerate equilibrium in cis-1,4-dimethylcyclohexane is either nonexistent, or is too small to be detected by methods of analyses employed. The 13C nmr data incidental to the study (chemical shifts, coupling constants, spin–lattice relaxation times, nuclear Overhauser enhancements, and 1-bond isotope shifts) are recorded for the title compound and its trans-isomer.

The nuclear Overhauser effect between phosphorus and hydrogen in selected organo phosphorus compounds

1976 ◽  
Vol 54 (12) ◽  
pp. 1918-1922 ◽  
Author(s):  
H. Beierbeck ◽  
R. Martino ◽  
John K. Saunders ◽  
Claude Benezra
Keyword(s):  
Nuclear Overhauser Effect ◽  
Lattice Relaxation ◽  
Dipole Interaction ◽  
Lattice Relaxation Time ◽  
Spin Lattice Relaxation ◽  
Phosphorus Compounds ◽  
Spin Lattice ◽  
Overhauser Effect ◽  
Internuclear Distances ◽  
Nuclear Overhauser

The nuclear Overhauser effect (nOe) observed between phosphorus and hydrogen together with carbon and phosphorus spin lattice relaxation time (T1) data are presented for a number of phosphorus containing compounds. The dominant mechanism for phosphorus relaxation is shown to be the dipole-dipole interaction between phosphorus and hydrogen. From the nOe and T1 data the determination of phosphorus–hydrogen internuclear distances is demonstrated.

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