CYCLOHEXANE COMPOUNDS: IV. NUCLEAR MAGNETIC RESONANCE SPECTRA OF SOME DERIVATIVES OF THE STEREOISOMERIC 3-AMINO-1,2-CYCLOHEXANEDIOLS

1963 ◽  
Vol 41 (9) ◽  
pp. 2331-2338 ◽  
Author(s):  
F. A. L. Anet ◽  
R. A. B. Bannard ◽  
L. D. Hall
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Room Temperature ◽  
Conformational Equilibrium ◽  
Chemical Shifts ◽  
Chloroform Solution ◽  
Coupling Constants ◽  
Order Analysis ◽  
First Order ◽  
Nuclear Magnetic Resonance Spectra ◽  
Derivatives Of

The n.m.r. spectra of 1α-methoxy-2β-hydroxy-3α-aminocyclohexane, 1α-methoxy-2α-hydroxy-3β-aminocyclohexane, their N-acetyl and O,N-diacetyl derivatives, ethoxy analogues, and 3α-amino-1α,2β-cyclohexanediol and 3β-amino-1α,2β-cyclohexanediol triacetates were measured in chloroform solution. From the chemical shifts of the O- and/or N-acetyl methyl protons it was possible to assign conformations to all the substituted derivatives and in most cases the assignments thus made were confirmed by first-order analysis of the multiplet pattern from the methine protons. In all cases, the conformations found were those predicted on simple conformational grounds and no evidence for a conformational equilibrium at room temperature was obtained from the coupling constants. In general, the coupling constants for the methine protons followed the pattern predicted by the Karplus equation. Acetylation of the 1α-alkoxy-2α-hydroxy-3β-aminocyclohexanes with acetic anhydride gave both the O,N-diacetyl derivative and the O,N,N-triacetyl derivative.

CYCLOHEXANE COMPOUNDS: VI. NUCLEAR MAGNETIC RESONANCE SPECTRA OF SOME DERIVATIVES OF THE STEREOISOMERIC 3-BROMO-1,2-CYCLOHEXANEDIOLS AND THE 2-BROMO-1,3-CYCLOHEXANEDIOLS

1966 ◽  
Vol 44 (7) ◽  
pp. 775-780 ◽  
Author(s):  
R. A. B. Bannard
Keyword(s):  
Magnetic Resonance ◽  
Proton Magnetic Resonance ◽  
Chemical Shifts ◽  
Coupling Constants ◽  
Angular Distortion ◽  
Order Analysis ◽  
First Order ◽  
Nuclear Magnetic Resonance Spectra ◽  
Derivatives Of ◽  
Magnetic Resonance Spectra

First-order analysis of the 60 Mc.p.s. proton magnetic resonance spectra of 1α-methoxy-2β-acetoxy-3α-bromocyclohexane, 1α-methoxy-2α-acetoxy-3β-bromocyclohexane, 1α-methoxy-2β-bromo-3α-acetoxycyclohexane, 1α-methoxy-2α-bromo-3β-acetoxycyclohexane, and the corresponding diol diacetates confirmed the stereochemical interrelationships of substituents which were assigned previously on chemical grounds, and demonstrated that the compounds exist in chair conformations. The chemical shifts of the methoxy methyl and acetoxy methyl protons did not provide reliable criteria for the assignment of conformations to these substituents in this series. The coupling constants of the methine protons followed, in general, the pattern predicted by the Karplus equation, and the smaller J2,3 values observed in the cis,trans compounds relative to those in the trans,trans compounds are interpreted mainly on the basis of conformational equilibration, upon which is superimposed a small dihedral angular distortion or a remote substituent orientational effect.

scholarly journals Application of multiplet structure deconvolution to extract scalar coupling constants from 1D nuclear magnetic resonance spectra

2021 ◽  
Vol 2 (2) ◽  
pp. 545-555
Author(s):  
Damien Jeannerat ◽  
Carlos Cobas
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Chemical Shifts ◽  
Coupling Constants ◽  
Scalar Coupling ◽  
Order Effects ◽  
Multiplet Structure ◽  
First Order ◽  
Nuclear Magnetic Resonance Spectra ◽  
Nuclear Magnetic

Abstract. Multiplet structure deconvolution provides a robust method to determine the values of the coupling constants in first-order 1D nuclear magnetic resonance (NMR) spectra. Functions simplifying the coupling structure for partners with spin larger than 1/2 and for doublets with unequal amplitudes were introduced. The chemical shifts of the coupling partners causing mild second-order effects can, in favourable cases, be calculated from the slopes measured in doublet structures. Illustrations demonstrate that deconvolution can straightforwardly analyse multiplet posing difficulties to humans and, in some cases, extract coupling constants from unresolved multiplets.

The High Resolution NMR Spectra of Pesticides. II. The DDT-Type Compounds

1969 ◽  
Vol 52 (5) ◽  
pp. 1074-1092 ◽  
Author(s):  
L H Keith ◽  
A L Alford ◽  
A W Garrison
Keyword(s):  
Nuclear Magnetic Resonance ◽  
High Resolution ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Coupling Constants ◽  
Aromatic Rings ◽  
Nuclear Magnetic Resonance Spectra ◽  
High Resolution Nmr ◽  
Related Compounds ◽  
Deshielding Effect

Abstract The high resolution nuclear magnetic resonance spectra of the DDT class of pesticides and related compounds are discussed, including a study of the resonances of the aromatic protons as they are affected by various substiluents. The CCl3 moiety on the α-carbon strongly deshields the ortho protons on the aromatic rings, and this deshielding effect is greatly enhanced by substitution of a chlorine ortho rather than para on the aromatic ring. These deshielding effects are explained by a consideration of the electronegativity of the substituents and the stereochemistry of the molecule. The chemical shifts and coupling constants are tabulated.

THE ANALYSIS OF NUCLEAR MAGNETIC RESONANCE SPECTRA: III. PYRIDINE AND DEUTERATED PYRIDINES

1957 ◽  
Vol 35 (12) ◽  
pp. 1487-1495 ◽  
Author(s):  
W. G. Schneider ◽  
H. J. Bernstein ◽  
J. A. Pople
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
High Resolution ◽  
Chemical Shifts ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Calculated Spectrum ◽  
Proton Resonance ◽  
Nuclear Magnetic Resonance Spectra ◽  
Spin Coupling Constants

The proton resonance spectra of pyridine, 2,6-pyridine-d2, 3-pyridine-d1, and 4-pyridine-d1 have been obtained for the pure liquids under conditions of high resolution. The spectra have been analyzed as proton groupings of AB2X2, AB2, perturbed ABX, and B2X2 respectively. The spin-coupling constants obtained from analysis of the simpler spectra of the deuterated molecules were used to suggest trial solutions for the analysis of the complicated AB2X2 spectrum of pyridine. A final set of chemical shifts and spin-coupling constants derived for pyridine give satisfactory agreement between the observed and calculated spectrum.

The High Resolution NMR Spectra of Pesticides. III. The Carbamates

1970 ◽  
Vol 53 (1) ◽  
pp. 157-179 ◽  
Author(s):  
L H Keith ◽  
A L Alford
Keyword(s):  
Nuclear Magnetic Resonance ◽  
High Resolution ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Coupling Constants ◽  
Hindered Rotation ◽  
Solvent Dependence ◽  
Nuclear Magnetic Resonance Spectra ◽  
High Resolution Nmr ◽  
Proton Resonances

Abstract The high resolution nuclear magnetic resonance spectra of 35 carbamate pesticides and a major metabolite of one pesticide are discussed. The chemical shifts and coupling constants are tabulated and reproductions of the more complex or unusual spectra are included. A concentration and solvent dependence of both the NH-proton and the NCH3-proton resonances of an N-monosubstituted carbamate is discussed. Hindered rotation is observed in the N,N-dimethylcarbamates, the thiolcarbamates and the dithiocarbamates, but not in the N-methylcarbamates.

scholarly journals Carbon-13 nuclear magnetic resonance spectra of oxazoles

1979 ◽  
Vol 57 (23) ◽  
pp. 3168-3170 ◽  
Author(s):  
Henk Hiemstra ◽  
Hendrik A. Houwing ◽  
Okko Possel ◽  
Albert M. van Leusen
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Coupling Constants ◽  
Proton Coupling ◽  
Nuclear Magnetic Resonance Spectra ◽  
C Nmr ◽  
Magnetic Resonance Spectra ◽  
Nuclear Magnetic

The 13C nmr spectra of oxazole and eight mono- and disubstituted derivatives have been analyzed with regard to the chemical shifts and the various carbon–proton coupling constants of the ring carbons. The data of the parent oxazole are compared with thiazole and 1-methylimidazole.

Carbon-13 nuclear magnetic resonance spectra of N-, O-, and S-methylated uracil and thiouracil derivatives

1978 ◽  
Vol 56 (5) ◽  
pp. 725-729 ◽  
Author(s):  
Ian W. J. Still ◽  
Nick Plavac ◽  
David M. McKinnon ◽  
Mohinder S. Chauhan
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Chemical Shift ◽  
General Type ◽  
Chemical Shifts ◽  
Pyrimidine Derivatives ◽  
Aromatic Substituent ◽  
Nuclear Magnetic Resonance Spectra ◽  
Derivatives Of ◽  
Thiouracil Derivatives ◽  
C Nmr

13C nmr chemical shifts have been recorded for a number of uracil, thiouracil, and pyrimidine derivatives. These data are discussed in relation to what is known of the lactam–lactim tautomerism in such systems and possible correlations of chemical shifts with normal aromatic substituent chemical shift parameters. The chemical shifts for the CH3 groups in simple methylated derivatives of uracil are very characteristic of the site of methylation and should prove useful as a tool for assigning structures to alkylated derivatives of this general type.

Synthesis and nuclear magnetic resonance spectra of some partially acylated β-D-glucopyranosides

1968 ◽  
Vol 46 (15) ◽  
pp. 2485-2493 ◽  
Author(s):  
A. P. Tulloch ◽  
A. Hill
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Chemical Shifts ◽  
Trimethylsilyl Ether ◽  
Ether Group ◽  
Nuclear Magnetic Resonance Spectra ◽  
The Difference ◽  
Derivatives Of ◽  
Magnetic Resonance Spectra ◽  
Nuclear Magnetic

The synthesis of ten new partially acylated derivatives of methyl β-D-glucopyranoside, all with an acyl group at C-6, is described. The nuclear magnetic resonance spectra of these compounds, and of a number of related derivatives, have been measured using pyridine, acetone-d6, and deuteriochloroform as solvents. When OH-4 is acylated, the H-6 signals are at higher field (by 0.1–0.3 p.p.m.) than when OH-4 is not acylated, but this effect is not observed when OH-3 is acylated. When a trimethylsilyl ether group is introduced at C-4 the difference between the chemical shifts of the H-6 protons (δA –δB) increases markedly. Estimation of JBX and JAX (where B is the H-6 proton at higher field and X is H-5), from spectra obtained using acetone-d6 and pyridine as solvents, shows that JBX < JAX when there is an acyl group at C-4 but JBX > JAX when there is no acyl group at C-4.

13C nuclear magnetic resonance spectra of 3,6-disubstituted pyridazines

1991 ◽  
Vol 69 (6) ◽  
pp. 972-977 ◽  
Author(s):  
Gottfried Heinisch ◽  
Wolfgang Holzer
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Chemical Shifts ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Molecular Orbital Calculations ◽  
Nuclear Magnetic Resonance Spectra ◽  
13C Nuclear Magnetic Resonance ◽  
Magnetic Resonance Spectra ◽  
Nuclear Magnetic

The 13C nuclear magnetic resonance spectra of 17 3,6-disubstituted pyridazine derivatives have been systematically analyzed. Chemical shifts and various 13C, 1H coupling constants are reported. Attempts were made to correlate these data with results obtained from semiempirical molecular orbital calculations as well as with substituent electronegativities and Taft's substituent constants σI and σR0. Key words: 3,6-disubstituted pyridazines, 13C NMR spectroscopy, 13C, 1H spin coupling constants.

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