The Transmission of Electronic Effects through Carbon, Oxygen, and Sulfur Atoms. Proton Magnetic Resonance Chemical Shifts for Toluenes, Acetophenones, and Thioanisoles1a,b

1966 ◽  
Vol 31 (6) ◽  
pp. 1872-1878 ◽  
Author(s):  
Sheldon H. Marcus ◽  
W. F. Reynolds ◽  
Sidney I. Miller
Keyword(s):  
Magnetic Resonance ◽  
Proton Magnetic Resonance ◽  
Chemical Shifts ◽  
Electronic Effects

Transmission of electronic effects. Proton magnetic resonance chemical shifts for benzyl halides in several solvents

1969 ◽  
Vol 34 (6) ◽  
pp. 1859-1866 ◽  
Author(s):  
Tai Yokoyama ◽  
Gary R. Wiley ◽  
Sidney I. Miller
Keyword(s):  
Magnetic Resonance ◽  
Proton Magnetic Resonance ◽  
Chemical Shifts ◽  
Electronic Effects ◽  
Benzyl Halides

Proton magnetic resonance studies of substituted 3,5-dimethylbenzenes: Influence of substituents on the methyl proton chemical shifts

1985 ◽  
Vol 23 (7) ◽  
pp. 521-523 ◽  
Author(s):  
Fadhil S. Kamounah ◽  
Ikbal. S. Al-Sheibani ◽  
Nazar L. Shibaldain ◽  
Salman R. Salman
Keyword(s):  
Magnetic Resonance ◽  
Proton Magnetic Resonance ◽  
Chemical Shifts ◽  
Methyl Proton ◽  
Magnetic Resonance Studies ◽  
Proton Chemical Shifts ◽  
Influence Of Substituents

Proton magnetic resonance studies at 220 MHz of alanine transfer RNA

1969 ◽  
Vol 47 (4) ◽  
pp. 480-484 ◽  
Author(s):  
Ian C. P. Smith ◽  
Tetsuo Yamane ◽  
R. G. Shulman
Keyword(s):  
Magnetic Resonance ◽  
Proton Magnetic Resonance ◽  
Chemical Shifts ◽  
Transfer Rna ◽  
Magnetic Resonance Studies ◽  
The Common ◽  
Line Widths ◽  
Increasing Temperature ◽  
Magnetic Resonance Spectra

Proton magnetic resonance spectra at 220 MHz of alanine transfer RNA do not permit assignments of individual peaks due to each of the common bases; only a peak attributable to protons at position eight in adenine can be assigned with certainty. Measurements of the relative areas of proton magnetic resonance peaks due to the base and ribose-1′ protons indicate that the ribose moieties of tRNA are not involved in bonds stronger than those experienced by the bases. Proton magnetic resonance peaks attributable to the methyl and dihydro protons of the rare bases can be distinguished in the 220 MHz spectra; the variation of their line widths and chemical shifts with increasing temperature indicates that the rare bases are located in regions of the alanine transfer RNA molecule which are more highly organized than indicated by an open cloverleaf model.

Proton magnetic resonance spectra of some benzo[b]thiophens. An investigation of substituent effects in a heteroaromatic system

1968 ◽  
Vol 21 (7) ◽  
pp. 1853 ◽  
Author(s):  
B Caddy ◽  
M Martin-Smith ◽  
RK Norris ◽  
ST Reid ◽  
S Sternhell
Keyword(s):  
Magnetic Resonance ◽  
Long Range ◽  
Proton Magnetic Resonance ◽  
Chemical Shifts ◽  
Substituent Effects ◽  
Spin Coupling ◽  
Heteroaromatic System ◽  
Spin Spin Coupling ◽  
Magnetic Resonance Spectra

N.m.r. data for 19 5-substituted and 13 polysubstituted benzo[b]thiophens are tabulated. The influence of the substituents at C5 on the chemical shifts of H4 and H6 is discussed. Long-range interproton spin-spin coupling between H3 and H7, and between H2 and H6, is general in benzo[b]thiophens. The vicinal coupling J6,7 in 5-substituted benzo[b]thiophens varies directly and linearly with the electronegativity of the substituents at C5.

Protonenresonanz-Spektroskopie ungesättigter Ringsysteme I

1965 ◽  
Vol 20 (10) ◽  
pp. 948-956 ◽  
Author(s):  
Harald Günther
Keyword(s):  
Magnetic Resonance ◽  
Concentration Dependence ◽  
Proton Magnetic Resonance ◽  
Chemical Shifts ◽  
Electron System ◽  
Coupling Constants ◽  
Resonance Signal ◽  
Aromatic Character ◽  
Additional Support ◽  
Magnetic Resonance Spectra

The proton magnetic resonance spectra of 1.6-methano- and 1.6-oxido-cyclodecapentaene are described and analyzed in terms of chemical shifts and coupling constants. The results are discussed in connection with the structure and possible aromatic character of these compounds. Measurements of the concentration dependence of the chloroform resonance signal in solutions of both compounds give additional support for the presence of a delocalized 10 π-electron system.

Proton Magnetic Resonance Spectra of Some Amphetamines and Related Compounds and Observations on Rotamer Populations

1971 ◽  
Vol 49 (19) ◽  
pp. 3143-3151 ◽  
Author(s):  
K. Bailey ◽  
A. W. By ◽  
K. C. Graham ◽  
D. Verner
Keyword(s):  
Hydrogen Bonding ◽  
Phenyl Ring ◽  
Proton Magnetic Resonance ◽  
Chemical Shifts ◽  
Coupling Constants ◽  
Side Chain ◽  
Amino Group ◽  
Ortho Position ◽  
Electronic Effects ◽  
Related Compounds

Data from the p.m.r. spectra of β-amino-, β-aminohydrochloride-, β-hydroxy-, and β-nitro-α-phenyl-propanes having methyl or methoxy substituants on the phenyl ring (37 compounds in all) are presented. The α and β protons of the side-chain give a pattern usually analyzable as ABX. The data are discussed in terms of correlations of coupling constants and chemical shifts with electronegativity of the substituent groups, steric and electronic effects, and apparent changes in rotamer populations. Hydrogen-bonding between the amino group of amphetamines and a methoxyl function at the ortho position in the phenyl ring is indicated for the salts but not the free bases.

Effect of solvent and anion upon the proton magnetic resonance spectrum of the 1-methylpyridinium ion

1968 ◽  
Vol 46 (17) ◽  
pp. 2787-2791 ◽  
Author(s):  
W. F. Reynolds ◽  
U. R. Priller
Keyword(s):  
Magnetic Resonance ◽  
Proton Magnetic Resonance ◽  
Chemical Shifts ◽  
Proton Magnetic Resonance Spectrum ◽  
Concentrated Solutions ◽  
Nonpolar Medium ◽  
Ion Proton ◽  
Acetonitrile Solutions ◽  
Proton Chemical Shifts ◽  
Pyridinium Ion

The proton magnetic resonance spectra of 1-methylpyridinium bromide and iodide have been measured over a range of concentrations in different solvents. It is found that, with the exception of acetonitrile solutions, the infinite dilution chemical shifts are related to solvent dielectric constant. Extrapolated shifts for a nonpolar medium agree with previously calculated chemical shifts for the pyridinium ion. Proton chemical shifts in concentrated solutions are affected by cation–anion interactions. These interactions are interpreted in terms of ion pair formation.

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