A conformational study of the adducts of 2′-deoxythymidine and 2,2,6,6-tetramethyl-1,4-piperidone-N-oxyl by 1H and 13C nuclear magnetic resonance

1985 ◽  
Vol 63 (1) ◽  
pp. 15-23 ◽  
Author(s):  
Frank E. Hruska ◽  
Maurice Berger ◽  
Jean Cadet ◽  
Mieczyslaw Remin
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Complex Mixture ◽  
Conformational Study ◽  
Γ Irradiation ◽  
Sugar Moiety ◽  
Nmr Data ◽  
13C Nuclear Magnetic Resonance ◽  
Conformational Properties ◽  
Nitroxide Free Radical ◽  
C Nmr

γ-Irradiation of oxygen-free, aqueous solutions of 2′-deoxythymidine in the presence of the organic nitroxide free radical, 2,2,6,6-tetramethyl-1,4-piperidone-N-oxyl (TAN), leads to a complex mixture of products in which the TAN moiety is linked to the C5 or C6 position of a 5,6-saturated thymine ring. Extensive 1H and 13C nmr data are provided for the eight TAN–dT adducts which are produced in the largest amounts. The results show that the conformational properties of the sugar moiety are dependent on the point of attachment of the TAN group and the configuration of the saturated thymine ring.

15N and 13C nuclear magnetic resonance of deoxydinucleotide monophosphates. II. Protonation of the homo dimers deoxycytidylyl-(3′,5′)-deoxycytidine, thymidylyl-(3′,5′)-thymidine, and deoxyadenylyl-(3′,5′)-deoxyadenosine in dimethyl sulfoxide

1990 ◽  
Vol 68 (11) ◽  
pp. 2033-2038 ◽  
Author(s):  
Giovanna Barbarella ◽  
Massimo Luigi Capobianco ◽  
Luisa Tondelli ◽  
Vitaliano Tugnoli
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Chemical Shift ◽  
Dimethyl Sulfoxide ◽  
Phosphate Group ◽  
Nmr Data ◽  
13C Nuclear Magnetic Resonance ◽  
C Nmr ◽  
Nuclear Magnetic

The preferential protonation sites of the homo dimers deoxycytidylyl-(3′,5′)-deoxycytidine, thymidylyl-(3′,5′)-thymidine, and deoxyadenylyl-(3′,5′)-deoxyadenosine were established by nitrogen-15 and carbon-13 NMR in dimethyl sulfoxide, in the presence of varying amounts of CF3COOH. The nitrogen-15 NMR data show that in d(CpC) the capability of the two N3 nitrogens to accept the proton is slightly different. In d(TpT) and d(ApA) the protonation of the phosphate group leads to significant variations of the chemical shift of the carbons adjacent to phosphorus. Keywords: deoxydinucleotides, protonation, 15N and 13C NMR.

13C-nuclear magnetic resonance spectra of oxiranes. Configuration of 1,2-epoxypropyl side chains in fungal metabolites

1978 ◽  
Vol 56 (24) ◽  
pp. 3117-3120 ◽  
Author(s):  
Suzanne Lesage ◽  
Arthur S. Perlin
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Side Chain ◽  
Fungal Metabolites ◽  
Trans Isomers ◽  
Model Compounds ◽  
Nmr Data ◽  
Nuclear Magnetic Resonance Spectra ◽  
13C Nuclear Magnetic Resonance ◽  
Cis And Trans ◽  
C Nmr

13C nmr data indicate that the epoxypropyl side chain of 'asperlin' (1) has a trans configuration. This assignment follows from associated measurements on model compounds, showing that the 13C chemical shift of an epoxypropyl CH3 group is close to either 17 ppm (trans isomers) or 13 ppm (cis isomers). Synthesized as oxirane derivatives related to 1 are diastereomeric pairs of 8-deoxy-6,7-cis- and -trans-epoxy-1,2:3,4-di-O-isopropylidene-α-D-galacto-octopyranoses.

Trimethylene sulfite conformations: Effects of sterically demanding substituants at C-4,6 on ring geometry as assessed by 1H and 13C nuclear magnetic resonance

1978 ◽  
Vol 56 (15) ◽  
pp. 2019-2024 ◽  
Author(s):  
Gerald W. Buchanan ◽  
Catherine M. E. Cousineau ◽  
Thomas C. Mundell
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Computer Analysis ◽  
Chemical Shifts ◽  
Tert Butyl ◽  
Nmr Data ◽  
Ring Geometry ◽  
13C Nuclear Magnetic Resonance ◽  
Sterically Demanding ◽  
C Nmr

1H and 13C nmr data for eight phenyl, diphenyl- and di-tert-butyl-2-oxo-1,3,2-dioxathianes, substituted at C-4 and/or C-6 are presented. Vicinal couplings obtained from 1H spectra by iterative computer analysis indicate chair geometries for all materials except trans-4,6-disubstituted compounds. 13C chemical shifts are corroborative.

13C nuclear magnetic resonance spectral and conformational analysis of naturally occurring tetrahydrofuran lignans

1979 ◽  
Vol 57 (4) ◽  
pp. 441-443 ◽  
Author(s):  
Sebastião F. Fonseca ◽  
Lauro E. S. Barata ◽  
Edmundo A. Rúveda ◽  
Paul M. Baker
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Conformational Analysis ◽  
Nmr Spectra ◽  
H Nmr ◽  
Naturally Occurring ◽  
Nmr Data ◽  
Benzylic Carbon ◽  
13C Nuclear Magnetic Resonance ◽  
C Nmr

The 13C nmr spectra of the naturally occurring stereoisomers of the tetrahydrofuran lignans were recorded and the signals assigned. Based on these assignments, on the observed sensitivity of the benzylic carbon shifts to the orientation of the aryl groups, and on the comparison with previously reported 1H nmr data, the most probable conformations for the mentioned stereoisomers are suggested.

Nuphar thiaspirane sulfoxides. 13C nuclear magnetic resonance determined configuration and utilization in the interconversion of thiaspirane stereochemical types

1978 ◽  
Vol 56 (1) ◽  
pp. 56-61 ◽  
Author(s):  
R. T. LaLonde ◽  
C. F. Wong
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Subsequent Reduction ◽  
13C Nuclear Magnetic Resonance ◽  
Sodium Borodeuteride ◽  
C Nmr ◽  
Nuclear Magnetic

The configuration of the sulfoxide oxygen in syn- and anti-thiobinupharidine sulfoxide was determined by employing the 13C nmr sulfoxidation increments of C-6. Establishment of the 13C nmr line assignments for C-6 included the study of the C-6 and C-6′ deuterated thiobinupharidine and the corresponding sulfoxides. Thermolysis of syn-thiobinupharidine sulfoxide in DMSO and subsequent reduction with sodium borodeuteride in methanol yielded thiobinupharidine, labelled with deuterium only at C-6, and thionuphlutine B, labelled with deuterium at both C-6 and C-6′. Treatment of the anti sulfoxide in xylene or DMSO resulted in no thiobinupharidine or thionuphlutine B. Similarly, syn-neothiobinupharidine sulfoxide gave neothiobinupharidine and a new thiaspirane, thionuphlutine C. These two compounds were not produced from anti-neothiobinupharidine sulfoxide heated in xylene.

13C nuclear magnetic resonance spectra of the spirobenzylisoquinoline alkaloids and related model compounds

1977 ◽  
Vol 55 (18) ◽  
pp. 3304-3311 ◽  
Author(s):  
Donald W. Hughes ◽  
Bala C. Nalliah ◽  
Herbert L. Holland ◽  
David B. MacLean
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Isoquinoline Alkaloids ◽  
Model Compounds ◽  
Related Model ◽  
Nuclear Magnetic Resonance Spectra ◽  
13C Nuclear Magnetic Resonance ◽  
C Nmr ◽  
Magnetic Resonance Spectra ◽  
Nuclear Magnetic

The natural abundance 13C nuclear magnetic resonance spectra of a number of spirobenzylisoquinoline alkaloids and related model compounds have been recorded. The carbon resonances of the alkaloids were assigned by comparison with the spectra of other isoquinoline alkaloids and with those of the model compounds. It has been shown that 13C nmr spectroscopy may be used to differentiate between diastereomers in this series.

Conformational Study of N-Alkyl 5,6-Dihydro-7h,12h-Dibenz[C,F]Azocines by Nuclear Magnetic Resonance Spectroscopy

1975 ◽  
Vol 53 (2) ◽  
pp. 167-176 ◽  
Author(s):  
Robert R. Fraser ◽  
Mohammad A. Raza ◽  
Roger N. Renaud ◽  
Robert B. Layton
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Magnetic Resonance Spectroscopy ◽  
Resonance Spectroscopy ◽  
Boat Conformation ◽  
Conformational Study ◽  
Conformational Properties ◽  
Boat Form ◽  
Twist Boat ◽  
Influence Of Substituents

The influence of substituents on the conformational properties of N-substituted 5,6-dihydro-7H,12H-dibenz[c,f]azocines and their conjugate acids was studied by n.m.r. spectroscopy. The position of the equilibrium between a rigid boat-chair and a flexible twist-boat conformation has been measured. The twist-boat conformation in deuterochloroform increased as the size of the substituent increased. However, the effect was opposite for the series of conjugate acids in trifluoroacetic acid.A number of inversion barriers for the [Formula: see text] and the [Formula: see text] equilibria in CDCl3 and TFA were determined. It was found that all barriers to interconversion were raised on protonation. The barrier to racemization for the twist-boat form of the quaternary methiodide of 1 was found to be >18 kcal/mol.

scholarly journals Conformational study of a series of 6-substituted 5,6,7,12-tetrahydrodibenzo[a,d]-cyclooctenes by nuclear magnetic resonance spectroscopy

1977 ◽  
Vol 55 (19) ◽  
pp. 3456-3463 ◽  
Author(s):  
Roger N. Renaud ◽  
John W. Bovenkamp ◽  
Robert R. Fraser ◽  
Jean-Louis A. Roustan
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Variable Temperature ◽  
Resonance Spectroscopy ◽  
Proton Nmr Spectroscopy ◽  
Conformational Study ◽  
Methyl Derivative ◽  
Conformational Properties ◽  
Different Temperatures ◽  
Keto Derivative ◽  
Twist Boat

The conformational properties of seven 5,6,7,12-tetrahydrodibenzo[a,d]cyclooctenes bearing substituents at C-6 have been studied using variable temperature proton nmr spectroscopy. The position of the equilibrium between boat-chair (BC) and twist-boat (TB) conformers has been measured in several solvents. In contrast to the unsubstituted dibenzocyclooctene, appreciable amounts of TB conformer are present when C-6 is substituted by alkyl, hydroxy, or cyano substituents. Measurements at different temperatures showed the TB form to possess the greater entropy. Barriers to the BC → TB interconversion were determined by coalescence studies, using both approximate and complete line shape methods. Barriers ranged from 10.1 kcal/mol for the 6-keto derivative to 16.7 kcal/mol for the 6-hydroxy-6-methyl derivative.

13C nuclear magnetic resonance and Raman investigations of aqueous carbon dioxide systems

1982 ◽  
Vol 60 (8) ◽  
pp. 1000-1006 ◽  
Author(s):  
Theresa M. Abbott ◽  
Gerald W. Buchanan ◽  
Peeter Kruus ◽  
Keith C. Lee
Keyword(s):  
Carbon Dioxide ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Linear Relationship ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Carbonate Ion ◽  
13C Nuclear Magnetic Resonance ◽  
Wide Range ◽  
C Nmr

13C-nmr spectra of carbon dioxide in water are reported for a wide range in pH. Chemical shifts were determined for the following species: CO2(g), CO2(aq), HCO3−(aq), CO32−(aq). A linear relationship was found between the shift of the 13C line and the fraction of carbonate ion calculated to be present, as well as between the ratio of the area under the 1067 cm−1 (carbonate) Raman peak to the sum of the area under the 1067 cm−1 and 1017 cm−1 (bicarbonate) peaks and the fraction carbonate.

scholarly journals Chemical constituents of the physodes of brown algae. Characterization by 1H and 13C nuclear magnetic resonance spectroscopy of oligomers of phloroglucinol from Fucus vesiculosus (L.)

1977 ◽  
Vol 55 (9) ◽  
pp. 1575-1582 ◽  
Author(s):  
James S. Craigie ◽  
A. Gavin McInnes ◽  
Mark A. Ragan ◽  
John A. Walter
Keyword(s):  
Molecular Weight ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Magnetic Resonance Spectroscopy ◽  
Chemical Constituents ◽  
Fucus Vesiculosus ◽  
Resonance Spectroscopy ◽  
Low Molecular Weight ◽  
13C Nuclear Magnetic Resonance ◽  
C Nmr

Alcoholic extracts of Fucus vesiculosus contain small quantities of low molecular weight polyphenols derived from phloroglucinol and 2,2′,4,4′,6,6′-hexahydroxybiphenyl. 1H and 13C nmr were used to identify two of these as 4-(2′′,4′′,6′′-trihydroxyphenoxy)-2,2′,4′,6,6′-pentahydroxybiphenyl and 4-(2′′-(2′′′,4′′′,6′′′-trihydroxyphenoxy)-4′′,6′′-dihydroxyphenoxy)-2,2′,4′, 6,6′-pentanydroxybiphenyl.

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