J. Pataki
Dec 1, 1973
Citations
0
Influential Citations
2
Citations
Journal
Tetrahedron
Abstract
Abstract Treatment of 3-methoxy-17β-acetoxyestra-2,5(10)-diene with perchloryl fluoride in aqueous dioxane or tetrahydrofuran yielded a 2-fluoro-3-ketosteroid with unusual properties. Unlike the known 2α-fluoro-19-nortestosterone, this fluoroketone possessing a 5(10) double bond easily lost hydrogen fluoride to form estradiol 17-acetate; aromatization took place on melting, on exposure to pyridine or acid or even during chromatography on silica gel or Florisil. Because of the Δ-5(10) structure and the absence of the C 19 Me group, it is difficult to infer the exact orientation of the 2-fluorine substituent from its effect on the NMR spectrum, CD or the CO absorption in the IR. However, the properties of certain derivatives suggested that the fluorine substituent was 2β. Treatment of the unsaturated fluorketone with peracid gave a mixture of epoxides which on basic hydrolysis furnished two 2-fluoro-10-hydroxy-17-acetoxyestr-4-en-3-ones epimeric at C 10 . The UV and NMR spectra of the 10α-hydroxy epimer indicated an equatorial 2β-orientation of fluorine, whereas the 10β-hydroxy epimer showed an axial 2β-fluorine substituent which could be isomerized by acid to the more stable equatorial 2α-configuration.