13C spectral parameters of some polycyclic hydrocarbons. II. Bicyclo[3,1,1]heptane, Tricyclo[3,1,1 ,03,6]heptane, Tricyclo[3,3,0,02,6]octane and Bicyclo[1,1,1]pentane

1981 ◽  
Vol 34 (4) ◽  
pp. 913 ◽  
Author(s):  
EW Della ◽  
E Cotsaris ◽  
PT Hine ◽  
. Pigou.P.E
Keyword(s):  
Chemical Shifts ◽  
Coupling Constants ◽  
Spectral Parameters ◽  
Polycyclic Hydrocarbons

Carbon-13 chemical shifts and one-bond carbon-hydrogen coupling constants of bicyclo[3,1,1]- heptane, tricyclo[3,1,1,03,6]heptane, tricyclo[3,3,0,02,6]octane and bicyclo[1,1,1]pentane are reported.

Studies of specifically fluorinated carbohydrates. Part I. Nuclear magnetic resonance studies of hexopyranosyl fluoride derivatives

1969 ◽  
Vol 47 (1) ◽  
pp. 1-17 ◽  
Author(s):  
L. D. Hall ◽  
J. F. Manville ◽  
N. S. Bhacca
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Angular Dependence ◽  
Chemical Shifts ◽  
Relative Orientation ◽  
Coupling Constants ◽  
Pyranose Ring ◽  
Spectral Parameters ◽  
Magnetic Resonance Studies ◽  
Nuclear Magnetic

A detailed study has been made of both the 1H and 19F nuclear magnetic resonance (n.m.r.) spectra of a series of hexopyranosyl fluoride derivatives. Some of the 1H spectra were measured at 220 MHz. The 1H spectral parameters define both the configuration and the conformation of each of these derivatives. Study of the 19F n.m.r. parameters revealed several stereospecific dependencies. The 19F chemical shifts depend upon, (a) the orientation of the fluorine substituent with respect to the pyranose ring and, (b) the relative orientation of other substituents attached to the ring; for acetoxy substituents, these configurational dependencies appear to be additive. The vicinal19F–1H coupling constants exhibit a marked angular dependence for which Jtrans = ca. 24 Hz whilst Jgauche = 1.0 to 1.5 Hz for [Formula: see text] and 7.5 to 12.6 Hz for [Formula: see text] The geminal19F–1H couplings depend on the orientation of the substituent at C-2; when this substituent is equatorial JF,H is ca. 53.5 Hz and when it is axial the value is ca. 49 Hz.

The planar conformation of 2-methylthiobenzaldehyde in solution

1983 ◽  
Vol 61 (1) ◽  
pp. 26-28
Author(s):  
Ted Schaefer ◽  
Rudy Sebastian
Keyword(s):  
Chemical Shifts ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Spectral Parameters ◽  
H Nmr ◽  
Heavy Atoms ◽  
Planar Conformation ◽  
Spin Coupling Constants ◽  
Spin Spin Coupling ◽  
Infrared Data

The 1H nmr spectral parameters are extracted for a 4 mol% solution of 2-methylthiobenzaldehyde in CCl4 at 305 K. The long-range spin–spin coupling constants involving the aldehydic and methyl protons are consistent only with a preferred conformation in which all heavy atoms are coplanar, as are the chemical shifts of the ring and methyl protons. This conclusion contradicts previous interpretations of the dipole moment, the nmr parameters, and of the infrared data for CCl4 solutions. The present data show that the O-syn and O-anti forms of the compound are present in roughly equal proportions.

13C and 119Sn NMR spectra of diphenyl- and dibenzyltin(IV) compounds and their complexes

1990 ◽  
Vol 55 (5) ◽  
pp. 1193-1207 ◽  
Author(s):  
Jaroslav Holeček ◽  
Antonín Lyčka ◽  
Karel Handlíř ◽  
Milan Nádvorník
Keyword(s):  
Internal Structure ◽  
Coordination Sphere ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Coupling Constants ◽  
Spectral Parameters ◽  
The Real ◽  
119Sn Nmr ◽  
C Nmr

13C and 119Sn NMR spectra of diphenyl- and dibenzyltin(IV) compounds have been studied in solutions of coordinating and non-coordinating solvents. Regions of values of the δ(119Sn) chemical shifts have been determined which characterize individual types of coordination of the central tin atom. The values of 13C NMR spectral parameters, the δ(13C) chemical shifts and nJ(119Sn, 13C) coupling constants, have been used to describe the real shapes of coordination sphere of the central tin atom and to discuss the internal structure of the organic substituents and of the nature of their bonding linkage to the tin atom.

Molecular Determinants for Drug-Receptor Interactions. 6. Proton 500 MHz NMR Spectra of the Narcotic Antagonists Naloxone and Naltrexone by Two-Dimensional 1H–1H Chemical Shift Correlation Spectroscopy

1986 ◽  
Vol 41 (2) ◽  
pp. 231-238 ◽  
Author(s):  
Bruno Perly ◽  
Giuseppe C. Pappalardo ◽  
Antonio Grassi
Keyword(s):  
Nmr Spectra ◽  
Chemical Shifts ◽  
Relaxation Times ◽  
Chair Conformation ◽  
Correlation Spectroscopy ◽  
Coupling Constants ◽  
Piperidine Ring ◽  
Two Dimensional ◽  
Spectral Parameters ◽  
Narcotic Antagonists

The full analysis of the 1H NMR spectra of naloxone and naltrexone (hydrochloride salts, in 2H2O solution) was performed by using an high-frequency (500 MHz) spectrometer and the recent technique of two-dimensional (2D ) homonuclear shift spectroscopy. The 1H-1H connectivities allowed detection of correlated resonances and assignments of multiplets. The shapes of the contour levels of the COSY 45 spectra were also used to check the relative signs of coupling constants. The refinement of spectral parameters of some component spin-systems of the complex spectra was performed by computerized iterative simulation of patterns.The spectral analysis provided proton coupling constants that allowed to establish a slightly distorted-chair conformation of the piperidine ring in both compounds.The magnetic non-equivalence found for the protons bonded to C-17 atom (part of the N-alkyl fragment) was found to be larger in naltrexone than in the analogous naloxone. This fact, while no significant differences were observable in the chemical shifts of corresponding protons of the rigid molecular backbone of the two narcotic antagonists under study, was assigned to smaller degree of internal conformational flexibility of the N-methylcyclopropyl group in naltrexone with respect to that of the N-methylallyl group in naloxone.The above findings appeared in good agreement with our previously proposed views based on results from 13C relaxation times studies, which suggested the possible correlation of the motional rates of the N-methyl-R group to the pharmacological activity of antagonist compounds. This would consist in a direct correlation between decreasing flexibility of the N-bonded fragment and increasing antagonistic potency.

Aqueous solution interaction of the methylmercuric cation with the dinucleotides CpG and dCpdG as studied by carbon-13 nuclear magnetic resonance spectroscopy

1986 ◽  
Vol 64 (10) ◽  
pp. 2038-2041 ◽  
Author(s):  
G. W. Buchanan ◽  
M. J. Bell
Keyword(s):  
Aqueous Solution ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Chemical Shifts ◽  
The Self ◽  
Coupling Constants ◽  
Resonance Spectroscopy ◽  
Spectral Parameters ◽  
Guanine Base ◽  
Nuclear Magnetic

13C nuclear magnetic resonance chemical shifts and 13C–31P coupling constants are reported for the self-complementary dinucleotides CpG and dCpdG in aqueous solution. The influence of methylmercuration at pH 6.0 on these spectral parameters has been examined. Results are interpreted in terms of preferential methylmercuration at the N-7 site of the guanine base of each dinucleotide with concomitant base destacking.

Nuclear magnetic resonance spectral parameters of α,α,α-trifluorotoluene

1969 ◽  
Vol 47 (18) ◽  
pp. 3313-3318 ◽  
Author(s):  
R. J. Kostelnik ◽  
M. P. Williamson ◽  
D. E. Wisnosky ◽  
S. M. Castellano
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Spectral Data ◽  
Chemical Shifts ◽  
Coupling Constants ◽  
Spectral Parameters ◽  
Nuclear Magnetic

The 60 and 100 MHz proton spectra of α,α,α-trifluorotoluene have been recorded and analyzed in terms of chemical shifts and coupling constants. The results of the analyses are compared and the values of the spectral parameters discussed. The nuclear magnetic resonance spectral data of 2-chloro-5-nitro-α,α,α-trifluorotoluene are also reported.

Nonbonded and interactions in 2-(4-chlorophenylthio) benzaldehyde in solution. An average skew conformation

1992 ◽  
Vol 70 (9) ◽  
pp. 2375-2380 ◽  
Author(s):  
Ted Schaefer ◽  
Lina B.-L. Lee ◽  
Rudy Sebastian
Keyword(s):  
Title Compound ◽  
Chemical Shifts ◽  
Minimum Energy ◽  
Lone Pair ◽  
Phenyl Group ◽  
Coupling Constants ◽  
Spectral Parameters ◽  
Text Interaction ◽  
The One

The 1H nuclear magnetic resonance spectral parameters are reported for 4.0 mol% solutions of 2-(4-chlorophenylthio) benzaldehyde in CS2/C6D12 and acetone-d6 at 300 K. In CS2 the O-syn conformer is 36% abundant, rising to 50% in acetone-d6. These abundances are compared to those of the O-syn and O-trans conformers of 2-(alkylthio) benzaldehydes in CCl4, solution. On the basis of coupling constants and chemical shifts it is concluded that the skew conformer of the title compound is very likely the one of minimum energy in both solutions. In the skew conformer the plane of the 4-chlorophenyl group lies perpendicular to the CSC plane and also to that of the other aromatic moiety. It is suggested that the [Formula: see text] interaction is rather weak and that the population of the O-syn conformer is controlled by the orientation of the mainly 3p lone-pair orbital on sulfur. At best, the [Formula: see text] interaction is attractive only when the 3p orbital lies perpendicular to the plane of the formyl group. The skew conformation of the title compound is contrasted to the skew conformation of 2-hydroxyphenyl phenyl sulfide in which, however, the role of the two aromatic planes is reversed; the 3p orbital now lies in or near the plane of the phenyl group COH due to an attractive [Formula: see text] interaction.

THE CONFORMATIONS IN SOLUTION OF trans-CYCLOHEXENE DIHALIDES AND cis- AND trans-1,2-CYCLOHEXANEDIOLS AND DERIVATIVES

1964 ◽  
Vol 42 (4) ◽  
pp. 893-910 ◽  
Author(s):  
R. U. Lemieux ◽  
J. W. Lown
Keyword(s):  
Chemical Shifts ◽  
Coupling Constants ◽  
Spectral Parameters ◽  
Conformational Equilibria ◽  
Karplus Relationship ◽  
In Trans ◽  
Cis And Trans ◽  
Isopropylidene Derivatives ◽  
Derivatives Of

trans-1,4,4-Trideuteriocyclohexene dichloride, dibromide, and diiodide and the 1,4,4-trideuterio-cis- and trans-1,2-cyclohexanediols together with their O-acetyl, O-tosyl, and O-isopropylidene derivatives were synthesized. Their nuclear magnetic resonance (NMR) spectral parameters were obtained with a spectrometer operating at 100 Mc.p.s. and employing double irradiation to establish the chemical shifts and the signs of the coupling constants. The interpretation of the data according to expectations based on the Karplus relationship, for dihedral angles and coupling constants, support the conformational equilibria assigned to the trans-dichloride and trans-dibromide of cyclohexene on the basis of dipole moment measurements (previously published results). The results indicate that trans-cyclohexene diiodide exists to about 84% in the diaxial conformation. In the case of the 1,2-cis-disubstituted cyclohexanes, the occurrence of the signal for the 3-hydrogen in trans relation to the 2-hydrogen at lower field than its geminal 3-hydrogen is assigned to the deshielding influence on the 3-hydrogen when in axial orientation by an opposing axial oxygen at the 1-position. Support for this contention was obtained by determination of the chemical shifts of the geminal hydrogens at the 3- and 5-positions of the cis- and trans-4-t-butyl-2,2,6,6-tetradeuterio-1-methylcyclohexanols. The conformational equilibria indicated for the 1,2-diol, 1,2-diacetoxy, and 1,2-ditosyloxy trans derivatives of 1,4,4-trideuteriocyclohexane by NMR parameters obtained from the spectrum of the O-isopropylidene derivatives of the trans-diol allowed conclusions regarding the non-bonded interaction energies involved. The Karplus relation had to be adjusted to the form, [Formula: see text] and [Formula: see text] to accommodate the results. Solvent effects on conformation are noted. Also, the investigation provided further evidence for the opposite signs of the coupling constants for geminal and vicinal hydrogens. A consideration of the chemical shifts observed for a variety of derivatives of cyclohexanol appears to indicate that intramolecular shielding effects are better accounted for on the basis of neighboring atomic groupings than on the basis of individual chemical bonds.

The analysis of the proton magnetic resonance spectra of heteroaromatic systems. II. Quinoline and its mononitroderivatives

1964 ◽  
Vol 17 (5) ◽  
pp. 558
Author(s):  
PJ Black ◽  
ML Heffernan
Keyword(s):  
Magnetic Resonance ◽  
Chemical Shifts ◽  
Double Resonance ◽  
Coupling Constants ◽  
Pure Liquid ◽  
Dilute Solution ◽  
Spectral Parameters ◽  
Nuclear Magnetic Resonance Spectra ◽  
Proton Chemical Shifts ◽  
Magnetic Resonance Spectra

The nuclear magnetic resonance spectra of quinoline, as a pure liquid and as a dilute solution in carbon tetrachloride and acetone, and of the 3-, 5-, 6-, 7-, and 8-nitroquinolines, all as dilute solutions in acetone, have been investigated at 100 Mc/s. Field sweep double resonance experiments, as well as chemical considerations, have been used to assign the spin multiplets to individual protons. The spectral parameters for these systems have been obtained by the iterative technique of Swalen and Reilly. The modifications to the proton chemical shifts and the coupling constants caused by the nitro substituent in various positions around the molecule are discussed in the light of previous related investigations.

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