| Autor: |
Selivanov SI, Solov'ev AIu, Morozkina SN, Shavva AG |
| Jazyk: |
ruština |
| Zdroj: |
Bioorganicheskaia khimiia [Bioorg Khim] 2007 May-Jun; Vol. 33 (3), pp. 324-31. |
| DOI: |
10.1134/s1068162007030053 |
| Abstrakt: |
All the signals in the 1H and 13C NMR spectra of some analogues of 7alpha-methyl-8alpha- and 6-oxa-8alpha-steroid estrogens were completely assigned. Considering the values of nuclear Overhauser effect and vicinal coupling constants, these steroids were shown to exhibit a fast, on the NMR time scale, conformational equilibrium arising due to the inversion of ring B. The conformer populations were obtained from a comparison of the experimental and theoretical values of the dihedral angles and the interproton distances. This conformational equilibrium was shown to depend on the nature of atom in position 6: for the 7alpha-methyl-6-oxa-8alpha analogues of the steroid estrogens, the population of the conformer with the pseudoaxial orientation of the 7alpha-methyl group was observed to be decreased compared with the 7alpha-methyl-8alpha analogue. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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