13C nuclear magnetic resonance spectra of some halosteroids, 6-ketosteroids, and related compounds

1979 ◽  
Vol 57 (23) ◽  
pp. 3069-3072 ◽  
Author(s):  
Herbert L. Holland ◽  
Everton M. Thomas
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Long Range ◽  
Chemical Shifts ◽  
Nuclear Magnetic Resonance Spectra ◽  
13C Nuclear Magnetic Resonance ◽  
Related Compounds ◽  
Magnetic Resonance Spectra ◽  
Nuclear Magnetic

The 13Cmr spectra of 21-haloprogesterones have been assigned, and chemical shifts compared with those of simple α-haloketones. In addition, the 13Cmr spectra of some C-5α and C-6β halosteroids are presented, and long range 13C—19F coupling observed between C-19 and the C-6β fluorine in some cases. The spectra of several oxygenated analogues and of a series of 5α-hydroxy-6-ketosteroids are also discussed.

13C nuclear magnetic resonance spectra of 3,6-disubstituted pyridazines

1991 ◽  
Vol 69 (6) ◽  
pp. 972-977 ◽  
Author(s):  
Gottfried Heinisch ◽  
Wolfgang Holzer
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Chemical Shifts ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Molecular Orbital Calculations ◽  
Nuclear Magnetic Resonance Spectra ◽  
13C Nuclear Magnetic Resonance ◽  
Magnetic Resonance Spectra ◽  
Nuclear Magnetic

The 13C nuclear magnetic resonance spectra of 17 3,6-disubstituted pyridazine derivatives have been systematically analyzed. Chemical shifts and various 13C, 1H coupling constants are reported. Attempts were made to correlate these data with results obtained from semiempirical molecular orbital calculations as well as with substituent electronegativities and Taft's substituent constants σI and σR0. Key words: 3,6-disubstituted pyridazines, 13C NMR spectroscopy, 13C, 1H spin coupling constants.

Microbial hydroxylation of steroids. 7. Hydroxylation of B-nortestosterone and related compounds by Rhizopus arrhizus ATCC 11145, and 13C nuclear magnetic resonance spectra of some B-norsteroids

1981 ◽  
Vol 59 (11) ◽  
pp. 1651-1655 ◽  
Author(s):  
Herbert L. Holland
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Rhizopus Arrhizus ◽  
Nuclear Magnetic Resonance Spectra ◽  
13C Nuclear Magnetic Resonance ◽  
Mechanism Of Oxidation ◽  
Related Compounds ◽  
Stereoelectronic Interactions ◽  
Magnetic Resonance Spectra ◽  
Nuclear Magnetic

The incubation of B-norandrost-4-ene-3-ones and B-nor-3β-hydroxyandrost-5-enes with Rhizopus arrhizus ATCC 11145 has been described. The products are consistent with a mechanism of oxidation at C-6 in which the stereochemistry of substitution at C-6 is controlled by stereoelectronic interactions in the substrate, and is not dictated by enzymic constraint during the reaction. The carbon-13 nuclear magnetic resonance spectra of several B-nor-Δ4 and Δ5 steroids have been presented.

13C-Nuclear Magnetic Resonance Investigations of Xanthine and Some of its N-Methylated Derivatives

1974 ◽  
Vol 29 (9-10) ◽  
pp. 475-478 ◽  
Author(s):  
Claude Nicolau ◽  
Knut Hildenbrand
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Chemical Shifts ◽  
Electron Densities ◽  
13C Chemical Shifts ◽  
Nuclear Magnetic Resonance Spectra ◽  
13C Nuclear Magnetic Resonance ◽  
Magnetic Resonance Spectra ◽  
Nuclear Magnetic

Abstract The 13C-Nuclear Magnetic Resonance spectra of xanthine, 1,3-dimethyl-xanthine (theophylline), 3,7-dimethyl xanthine (theobromine) and 1,3,7-trimethylxanthine (caffeine) were obtained and the lines assigned. Protonation-and N-Methylation parameters are derived by comparison of the 13C-chemical shifts of the protonated cations with those of the neutral molecules and also with those of the xanthine cation. The shifts are discussed in terms of variations in the shielding at the different C-atoms induced by N-methylation and protonation. Approximate correlations are found between the 13C-chemical shifts and the π-electron densities at the C-atoms

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