STEREOCHEMICAL STUDIES: V. REARRANGEMENTS ACCOMPANYING ATTEMPTS TO EPIMERIZE 4-OXA-3-OXO-5α-CHOLESTANE AND 4-OXA-3-OXO-5β-CHOLESTANE BY BREWSTER AND KUCERA'S METHOD

1966 ◽  
Vol 44 (3) ◽  
pp. 279-295 ◽  
Author(s):  
W. H. Lunn ◽  
J. T. Edward ◽  
Seymour Meyerson
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Structural Features ◽  
Ring Structure ◽  
Skeletal Rearrangement ◽  
Nuclear Magnetic Resonance Spectra ◽  
Highly Sensitive ◽  
Hydrolysis Of ◽  
Magnetic Resonance Spectra ◽  
Nuclear Magnetic

Epimerization of 4-oxa-3-oxo-5α-cholestane by Brewster and Kucera's method gave only a 23% yield of the 5β-lactone; several other compounds were formed, apparently via skeletal rearrangement during hydrolysis of the tosylate. The attempted epimerization of 4-oxa-3-oxo-5β-cholestane gave mainly unsaturated acids, but no 5α-lactone (a small amount of skeletal rearrangement also occurred). Both epimers undergo rearrangement to γ-lactones when treated with trifluoroacetic acid.Mass spectra, used in conjunction with infrared and nuclear magnetic resonance spectra and other data to make structural assignments, were found to be highly sensitive to certain structural features. In particular, they can usually distinguish sharply between molecules that contain a pendant ring structure and those that do not.

Isomerisierung und Hydrolyse biozider cyclischer Sulfitester-Endosulfan und 10.10-Dihydro-Endosulfan / Isomerisation and Hydrolysis of Biocidal Cyclic Sulfurous Acid Esters-Endosulfan and 10,10-Dihydro-endosulfan

1973 ◽  
Vol 28 (11-12) ◽  
pp. 741-745
Author(s):  
Horst Schlüter ◽  
Karlheinz Ballschmiter
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Sulfurous Acid ◽  
Nuclear Magnetic Resonance Spectra ◽  
Hydrolysis Of ◽  
Acid Esters ◽  
Magnetic Resonance Spectra ◽  
Nuclear Magnetic

Two isomeric 10,10-dihydro-endosulfans are isolated, and their configurations are determined by means of infrared and nuclear magnetic resonance spectra.The isomerisation of the sulfurous ester ring of 10,10-dihydro-endosulfan yields a 67/33 ratio for the α/β isomers, while the endosulfan gives a 45/55 ratio.Both the 10,10-dihydro-endosulfans prove to be less easily hydrolised than endosulfan.

meso- and dl - .alpha.,.alpha.' -Bis(difluoramino)bibenzyls. Preparation and nuclear magnetic resonance spectra

1967 ◽  
Vol 32 (2) ◽  
pp. 466-468 ◽  
Author(s):  
Frederic Allan Johnson ◽  
Carolyn Haney ◽  
Travis Edward Stevens
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Nuclear Magnetic Resonance Spectra ◽  
Magnetic Resonance Spectra ◽  
Nuclear Magnetic
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