Nuclear magnetic resonance spectra of 2-pyrazolines

1968 ◽  
Vol 46 (5) ◽  
pp. 810-812 ◽  
Author(s):  
Wallace S. Brey Jr. ◽  
Carmen M. Valencia
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Phenyl Group ◽  
Coupling Constants ◽  
Spectral Parameters ◽  
Vicinal Coupling Constants ◽  
Nuclear Magnetic Resonance Spectra ◽  
Rigid Conformation ◽  
Cis And Trans ◽  
Nuclear Magnetic

The nuclear magnetic resonance spectral parameters for a series of 3-carbomethoxy-2-pyrazolines are presented and discussed. Substitution of a phenyl group at position-5 has a large effect on the relative chemical shift of the two protons at position-4, although a carbomethoxy group at position-5 has little effect. The cis and trans vicinal coupling constants in compounds with two protons in position-4 are nearly equal and differ from the values found when there is a substituent in position-4. The presence of three groups in positions-4 and -5 appears to hold the ring in a rigid conformation. The line width for the hydrogen attached to nitrogen depends upon the number of phenyl groups in position-5.

The nuclear magnetic resonance spectra and stereochemistry of 4-Benzoyloxy-1-thiaflavans

1967 ◽  
Vol 20 (10) ◽  
pp. 2235 ◽  
Author(s):  
GF Katekar ◽  
AG Moritz
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Double Resonance ◽  
Heterocyclic Ring ◽  
Coupling Constants ◽  
Spectral Parameters ◽  
Nuclear Magnetic Resonance Spectra ◽  
Cis And Trans ◽  
Magnetic Resonance Spectra ◽  
Nuclear Magnetic

The nuclear magnetic resonance spectra of cis- and trans-4-benzoyloxy- 1-thiaflavan in deuterochloroform have been investigated at 60 Mc/s. The spectral parameters for the heterocyclic ring protons have been obtained by analysis of the frequency-sweep double-resonance spectra and verified by an iterative technique using a digital computer. Long- range coupling constants were observed between the protons at C 4 and C 5 (J 0.8 c/s) and between the protons at C 2 and C 4 (J 0.2 c/s) for the cis isomer.

Flavan derivatives. XXI. Nuclear magnetic resonance spectra, configuration, and conformation of flavan derivatives

1968 ◽  
Vol 21 (8) ◽  
pp. 2059 ◽  
Author(s):  
JW Clark-Lewis
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Chemical Shifts ◽  
Heterocyclic Ring ◽  
Coupling Constants ◽  
Vicinal Coupling Constants ◽  
Nuclear Magnetic Resonance Spectra ◽  
Configuration And Conformation ◽  
Magnetic Resonance Spectra ◽  
Nuclear Magnetic

Nuclear magnetic resonance spectra of 80 compounds belonging to several classes of flavan derivative have been analysed, and chemical shifts and coupling constants of heterocyclic ring protons and aromatic protons are tabulated and discussed. Compounds examined include flav-2-enes, flav-3-enes, 3-substituted flavanones and flavans, 2- and 4-substituted isoflavans, 3,4-disubstituted flavans, and flavan-4-ols. The geometrical configurations of substituents in the heterocyclic ring follow unequivocally from the magnitudes of the vicinal coupling constants.

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.

High-resolution nuclear-magnetic-resonance spectra of hydrocarbon groupings - V. ABCX spectra of vinyl fluoride and 3-methylbut-l-ene

1961 ◽  
Vol 263 (1312) ◽  
pp. 136-148 ◽  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
High Resolution ◽  
Coupling Constants ◽  
Vinyl Fluoride ◽  
General Properties ◽  
Nuclear Magnetic Resonance Spectra ◽  
Magnetic Resonance Spectra ◽  
Nuclear Magnetic

Some general properties of ABCX -type spectra are discussed. It is shown that it is possible to deduce from such spectra the relative signs of all inter-nuclear coupling constants. Analyses are presented of the hydrogen (proton) spectra from the vinyl groups of vinyl fluoride and 3-methylbut-l-ene, and of the fluorine spectrum of the former molecule. It is shown that all HF coupling constants in vinyl fluoride are of the same sign as the cis and trans HH coupling constants.

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