13C Nuclear Magnetic Resonance Studies. 29. 13C Spectra of Some Alicyclic Methyl Esters

1973 ◽  
Vol 51 (13) ◽  
pp. 2092-2097 ◽  
Author(s):  
M. Gordon ◽  
S. H. Grover ◽  
J. B. Stothers
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Carboxylic Acid ◽  
Magnetic Resonance ◽  
Methyl Esters ◽  
Membered Ring ◽  
Model Compounds ◽  
Magnetic Resonance Studies ◽  
13C Nuclear Magnetic Resonance ◽  
Acid Esters ◽  
Shielding Effects

The shielding effects of the carbomethoxyl group on neighboring carbons in the cyclohexane and trans-decalin ring systems have been characterized by 13C n.m.r. examination often model compounds. The data show that sufficient differences are exhibited by axial and equatorial groups to permit stereochemical assignments in related systems. The observed trends are compared with those produced by other functional groups. The three-, four-, and five-membered ring cycloalkae carboxylic acid esters were also examined.

13C Nuclear Magnetic Resonance Studies. 38. Examination of the Long-range Shielding Effects of the Hydroxyl Group in Alicyclic Systems

1974 ◽  
Vol 52 (6) ◽  
pp. 870-878 ◽  
Author(s):  
S. H. Grover ◽  
J. B. Stothers
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Spectral Analysis ◽  
Magnetic Resonance ◽  
Substituent Effects ◽  
Hydroxyl Group ◽  
Magnetic Resonance Studies ◽  
13C Nuclear Magnetic Resonance ◽  
Steric Crowding ◽  
Direct Contrast ◽  
Shielding Effects

The substituent effects of the hydroxyl group on the 13C shieldings of the trans-decalols and the 10-methyl-trans-decalols have been determined. The shifts for the carbons three and four bonds from the site of substitution depend strongly on their orientation with respect to the hydroxyl group. While the latter have not been widely recognized, these δ effects are valuable for spectral analysis and stereochemical assignments since these range up to 3.4 p.p.m. In direct contrast to the well established trends for γ effects, steric crowding of δ nuclei causes marked downfield shifts. The corresponding effects in several steroids are illustrated.

13C Nuclear Magnetic Resonance Studies. 47. 13C Spectra of some exo-Methylenecycloalkanes and -norbornanes

1975 ◽  
Vol 53 (4) ◽  
pp. 589-595 ◽  
Author(s):  
S. H. Grover ◽  
J. B. Stothers
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Carbonyl Group ◽  
Ring System ◽  
Magnetic Resonance Studies ◽  
13C Nuclear Magnetic Resonance ◽  
Methylene Group ◽  
Shielding Effects ◽  
Nuclear Magnetic

The shielding effects of the exo-methylene group on neighboring carbons in several cycloalkanes, methylcyclohexanes, and in the norbornane ring system have been characterized by 13C n. m. r. examination of 28 compounds. The results are compared with those for the carbonyl group and the utility of these data for structural elucidations is discussed. The more distinctive trends exhibited by the methyl carbons in these systems are compared with those for cyclohexanes, cyclohexanones, norbornanes, and norcamphors.

13C nuclear magnetic resonance studies. 85. 13C spectra of several ring-contracted and -expanded steroids

1979 ◽  
Vol 57 (13) ◽  
pp. 1550-1556 ◽  
Author(s):  
Vinod Dave ◽  
J. B. Stothers
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Membered Ring ◽  
Magnetic Resonance Studies ◽  
Systematic Examination ◽  
13C Nuclear Magnetic Resonance ◽  
Nuclear Magnetic

The 13Cmr spectra of several cholestanes including 13 A-homo-B-nor derivatives, 11 A-homo derivatives, and 8 B-nor examples have been examined. In addition the 13C data for a few of the corresponding androstanes and 16 precursors in the cholestane series are reported. Examples in both the 5α- and 5β-cholestane families were included. These results represent the first systematic examination of the 13C spectra of A-homo-B-nor steroids and should be useful for the characterization of other members in each series. These data also permit some tentative conclusions regarding the favored conformation for the seven-membered ring in the A-homo derivatives.

scholarly journals 13C nuclear magnetic resonance studies. 64. The 13C spectra of a variety of bicyclo[3.2.1]octanols

1977 ◽  
Vol 55 (5) ◽  
pp. 841-848 ◽  
Author(s):  
J. B. Stothers ◽  
C. T. Tan
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Nmr Spectra ◽  
Substituent Effects ◽  
Ring System ◽  
Hydroxyl Group ◽  
Magnetic Resonance Studies ◽  
13C Nuclear Magnetic Resonance ◽  
C Nmr ◽  
Shielding Effects

The 13C nmr spectra of a series of 20 bicyclo[3.2.1]octanols and -octenols have been determined to examine the shielding effects of the hydroxyl group on the skeletal carbons in this ring system. For comparison, the previously unreported data for a few closely related alcohols in the [2.1.1], [2.2.1], and [3.2.2] systems were also collected. The utility of these substituent effects for configuraional and conformational assignments is discussed.

X-Ray crystallographic and 13C nuclear magnetic resonance studies of 3,4,5,6-tetrahydro-2H-1,3,4-oxadiazin-2-ones derived from ephedrine and pseudoephedrine

Tetrahedron ◽  
2001 ◽  
Vol 57 (49) ◽  
pp. 9789-9798 ◽  
Author(s):  
Shawn R Hitchcock ◽  
George P Nora ◽  
David M Casper ◽  
Michael D Squire ◽  
Christopher D Maroules ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Magnetic Resonance Studies ◽  
X Ray ◽  
13C Nuclear Magnetic Resonance ◽  
Nuclear Magnetic
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