Synthesis,structure and reactions of seco-steroids containing a medium-sized ring—IX : Reactions of Δ1(10)-unsaturated 5-oxo-5,10-seco-steroids with hydroxylamine and n-methylhydroxylamine |
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Authors: | MLj Mihailović Lj Lorenc Z Maksimović J Kalvoda |
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Institution: | Department of Chemistry, Faculty of Sciences, University of Belgrade, Belgrade, Yugoslavia;Institute for Chemistry, Technology and Metallurgy, Belgrade, Yugoslavia;Forschungslaboratorien der Division Pharmazeutika der CIBA-GEIGY AG, Basel, Switzerland |
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Abstract: | When treated with hydroxylamine or N-methylhydroxylamine, in the presence of proton donor catalysts, trans-Δ1(10)-unsaturated 5-oxo-5,10-seco-steroids, such as 3 (but not the corresponding diastereomeric cis-compounds), are converted stereospecifically and in good yield to isoxazolidine derivatives (e.g. 4 and 13), resulting from transannular 1,3-dipolar addition of the intermediately formed oximes and nitrones to the trans-double bond in the cyclodecene ring moiety of the seco-steroid system. Reactions are described and physical evidence is presented which establish the constitution and configuration of the isoxazolidine-containing cycloaddition products, and the mechanistic and steric course of this transannular ring closure process is discussed. |
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Keywords: | Correspondence to: Department of Chemistry Faculty of Sciences Studentski trg 16 P O Box 550 11001 Belgrade Yugoslavia |
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