scholarly journals Intramolecular Interaction between Hydroxyl Group and π-Electrons. XVIII. Proton Magnetic Resonance Spectra of Aryldimethylcarbinols and Related Compounds

1963 ◽  
Vol 36 (1) ◽  
pp. 1-4 ◽  
Author(s):  
Michinori \={O}ki ◽  
Hiizu Iwamura
Keyword(s):  
Magnetic Resonance ◽  
Proton Magnetic Resonance ◽  
Intramolecular Interaction ◽  
Hydroxyl Group ◽  
Related Compounds ◽  
Magnetic Resonance Spectra

Aza-analogues of pteridine. III. Some monomethoxy-1,2,4,6,8-pentaazanaphthalenes and related compounds

1971 ◽  
Vol 24 (3) ◽  
pp. 633 ◽  
Author(s):  
DJ Brown ◽  
T Sugimoto
Keyword(s):  
Magnetic Resonance ◽  
Proton Magnetic Resonance ◽  
Triethyl Orthoformate ◽  
Ionization Constants ◽  
Reductive Cyclization ◽  
Ultraviolet Spectra ◽  
Chloro Derivative ◽  
Related Compounds ◽  
Magnetic Resonance Spectra

4-Hydrazino-2-methoxy-6-methyl-5-nitropyrimidine reacted with triethyl orthoformate to give the ethoxymethylenehydrazino analogue or 4-methoxy-6-methyl-7-nitro-1,2,3a,5-tetraazaindene according to conditions. The first of these products was converted by reductive cyclization and subsequent dehydrogenation into 7-methoxy-5-methyl- 1,2,4,6,8-pentaazanaphthalene. Attempts to hydrolyse this and related compounds to the corresponding 7-hydroxypentaazanaphthalenes failed and direct approaches via appropriate 2-hydroxypyrimidines gave only 4- hydroxy-7-nitrotetraazaindenes. ��� 5-Alkoxypentaazanaphthalenes were prepared via 1,2-dihydropentaaza- naphthalene or its 5-chloro derivative. Nucleophilic displacements were used to make the 5-hydroxy, 5-methylthio, 5-diethylamino, and other analogues from 5-methoxy-3-methylpentaazanaphthalene. ��� The ionization constants, ultraviolet spectra, and proton magnetic resonance spectra of members of both bicyclic series are tabulated and discussed.

REACTIONS OF AMIDES AND RELATED COMPOUNDS: III. N.M.R. INVESTIGATION OF THE PROTONATION OF N,N-DIMETHYLNITROSOAMINE, N,N-DIETHYLNITROSOAMINE, AND N-NITROSOPIPERIDINE

1966 ◽  
Vol 44 (2) ◽  
pp. 105-109 ◽  
Author(s):  
Stephen J. Kuhn ◽  
John S. McIntyre
Keyword(s):  
Sulfuric Acid ◽  
Magnetic Resonance ◽  
Perchloric Acid ◽  
Trifluoroacetic Acid ◽  
Proton Magnetic Resonance ◽  
Acid Solutions ◽  
Concentrated Sulfuric Acid ◽  
Related Compounds ◽  
Equimolar Solution ◽  
Magnetic Resonance Spectra

Protonation of N,N-dimethylnitrosoamine has been investigated by dissolving the nitrosoamine in different acids and recording the proton magnetic resonance spectra of these solutions. Concentrated sulfuric acid, sulfuric acid monohydrate, perchloric acid (72%), trifluoroacetic acid, and fluorosulfuric acid have been used in this study. Only in fluorosulfuric acid near 0 °C and lower was a new signal observed for the protonated nitrosoamine molecule. Integration of the peaks has shown that only one proton is captured by the nitrosoamine. The following structure is suggested for the protonated nitrosoamine.[Formula: see text]The n.m.r. spectra of fluorosulfuric acid solutions of N,N-diethylnitrosoamine and N-nitrosopiperidine also show separate signals for the captured proton.The n.m.r. spectrum of an equimolar solution of N,N-dimethylnitrosoamine, N,N-dimethylformamide, and trifluoroacetic acid in 2-nitropropane indicates that N,N-dimethylnitrosoamine is a weaker base.

scholarly journals The barrier to the conformational interconversion of 1,4-dimethylenecyclohexane and related compounds

1969 ◽  
Vol 47 (15) ◽  
pp. 2911-2913 ◽  
Author(s):  
Maurice St-Jacques ◽  
Michel Bernard
Keyword(s):  
Magnetic Resonance ◽  
Proton Magnetic Resonance ◽  
Kcal Mole ◽  
Temperature Dependent ◽  
Conformational Interconversion ◽  
Spectral Changes ◽  
Related Compounds ◽  
Magnetic Resonance Spectra

The proton magnetic resonance spectra of 1,4-cyclohexanedione, 1,4-dimethylenecyclohexane, and 1,4-difluoromethylenecyclohexane have been studied at various temperatures; the spectra of the last two compounds were found to be temperature dependent. ΔF≠ values of 7.5 and 6.5 kcal/mole, respectively, were estimated from the spectral changes.

THE PROTON MAGNETIC RESONANCE SPECTRA AND TAUTOMERIC EQUILIBRIA OF ALDOSES IN DEUTERIUM OXIDE

1966 ◽  
Vol 44 (3) ◽  
pp. 249-262 ◽  
Author(s):  
R. U. Lemieux ◽  
J. D. Stevens
Keyword(s):  
Aqueous Solution ◽  
Magnetic Resonance ◽  
Proton Magnetic Resonance ◽  
Chemical Shifts ◽  
Deuterium Oxide ◽  
Chair Conformation ◽  
Hydroxyl Group ◽  
Equatorial Orientation ◽  
Tautomeric Equilibria ◽  
Magnetic Resonance Spectra

The proton magnetic resonance spectra of D-xylose, D-lyxose, D-arabinose, D-ribose, D-glucose, D-mannose, and D-galactose were determined at 100 Mc.p.s. in deuterium oxide. The chemical shifts and structures of a number of ring protons in these compounds were determined either by spin-decoupling experiments or by synthesis of specifically deuterated compounds. The proton magnetic resonance parameters are shown to provide considerable information on the conformations and tautomeric equilibria for the sugars in aqueous solution. It is concluded that, for aldopyranoses in a chair conformation, the chemical shift of equatorial protons at a given position is virtually independent of configurational changes at other positions. However, an axial proton is shielded about 0.3 p.p.m. less by an axial hydroxyl group at a neighboring position than when the hydroxyl group is in an equatorial orientation. An axial hydroxyl group leads to deshielding of an opposing axial proton by about 0.35 p.p.m. By using the chemical shifts of the ring protons of β-D-xylopyranose and β-D-glucopyranose as reference point, the chemical shifts of protons in other pyranose structures could be anticipated to within a useful degree of accuracy.Evidence was obtained that D-ribose and 2-deoxy-D-ribose exist in aqueous solution both in the pyranose and in the furanose forms. None of the other pentoses showed readily detectable amounts of the furanose forms at equilibrium. Although D-allose does not give readily detectable amounts of the furanose forms when at equilibrium in aqueous solutions, D-altrose does. D-Talose showed only two forms, one of which was the β-pyranose structure.

Conformational interconversion of 3,3,5,5-tetramethylmethylenecyclohexane and related compounds

1970 ◽  
Vol 48 (15) ◽  
pp. 2386-2392 ◽  
Author(s):  
Maurice St-Jacques ◽  
Michel Bernard ◽  
Cambyse Vaziri
Keyword(s):  
Magnetic Resonance ◽  
Proton Magnetic Resonance ◽  
Conformational Interconversion ◽  
Spectral Changes ◽  
Related Compounds ◽  
Magnetic Resonance Spectra

The proton magnetic resonance spectra of compounds 1 to 4 have been studied at various temperatures. The spectral changes observed for 2, 3, and 4 are interpreted in terms of interconverting chair conformations.

The analysis of the proton magnetic resonance spectra of heteroaromatic systems. IV. Benzofuran, indole, and related compounds

1965 ◽  
Vol 18 (3) ◽  
pp. 353 ◽  
Author(s):  
PJ Black ◽  
ML Heffernan
Keyword(s):  
Magnetic Resonance ◽  
Proton Magnetic Resonance ◽  
Coupling Constants ◽  
Spectral Parameters ◽  
Related Compounds ◽  
Magnetic Resonance Spectra

The proton magnetic resonance spectra of benzofuran, dibenzofuran, indole, 7-azaindole, carbazole, and 4-azacarbazole (α-carboline) have been investigated at 100 Mc/s, and the spectral parameters for these molecules have been obtained. The presence of cross-ring coupling constants involving the NH proton of indole and carbazole is reported.

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