Article ID Journal Published Year Pages File Type
10848129 Steroids 2005 8 Pages PDF
Abstract
Oxidation of 4-nitro-17β-estradiol (1) with the peroxidase/H2O2 system gave the symmetric C2-linked dimer (3) through phenoxy radical coupling. Similar oxidation of 2-nitro-17β-estradiol (2), in which the nitro group is coplanar with the aromatic ring, yielded 9α- and 9β-hydroxy-2-nitro-17β-estradiol (4a,b), (17β)-2-nitroestra-1(10),2,4,9(11)-tetraene-3,17-diol (5), and (12α,17β)-2-nitroestra-1(10),2,4,9(11)-tetraene-3,12,17-triol (6). With higher concentrations of H2O2, the novel secoestra-1(10),2,4-trien-9-one derivative 7 was obtained from 2. Theoretical calculations suggested that the peculiar behavior of 2 may be due to the generation of a relatively stable radical intermediate at C9, which would then be converted to the reactive quinone methide 8. The chemistry described in this paper appears to be an intriguing example of control of the site of substitution over evolution of phenoxy radicals, and opens new vistas toward selective oxyfunctionalization of the estrane skeleton.
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Life Sciences Biochemistry, Genetics and Molecular Biology Biochemistry
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