Reaction of trimethylsilylimidazole with 5,10 beta-epoxy-3-ketosteroids: enolization and aromatization of the A-ring.
The reaction of trimethylsilylimidazole (TSIM) and 3-keto-5,10-epoxy-nor-19-methylandrostanone 3 and its 17-acetate analog 4 was examined at two different temperatures. In both compounds, reaction at 90 degrees C gave predominantly a delta 3-silyl-enol ether plus a minor product as a result of the epoxide ring opening. Under reflux conditions, besides the aforementioned products, aromatization of the A-ring was observed as a major process. The results suggest the potential use of silylation reactions with epoxyketones towards the synthesis of aromatic compounds.
Department of Chemistry, Northeastern University, Boston, MA 02115.
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Kulkarni
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Abdel-Baky
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Le Quesne
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Vouros
D000731:Androstanes; D000732:Androstanols; D055598:Chemical Phenomena; D002621:Chemistry; D006358:Hot Temperature; D007093:Imidazoles; D013058:Mass Spectrometry; D012825:Silicon; D014297:Trimethylsilyl Compounds
D000731:Androstanes; D000732:Androstanols; D007093:Imidazoles; D014297:Trimethylsilyl Compounds; C060841:3-keto-5,10-epoxy-nor-19-methylandrostane-17-acetate; C054025:1-(trimethylsilyl)-1H-imidazole; C060840:3-keto-5,10-epoxy-19-normethylandrostan-17-one; D012825:Silicon