Regio- and stereoselective access to novel ring-condensed steroidal isoxazolines

Gergo Mótyán, Zalán Kádár, Dóra Kovács, János Wölfling, Éva Frank

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

Novel 5α-androstanes containing an isoxazoline moiety condensed to ring A or D were efficiently synthetized by 1,3-dipolar cycloadditions of aryl nitrile oxides to steroidal α,β-unsaturated ketones. During the ring closures, regioisomers in which the O terminus of the nitrile oxide dipoles is attached to the β-carbon of the dipolarophile were formed in a stereoselective manner to furnish exclusively 1α,2α- or 15β,16β-condensed heterocycles. The cyclic enone moiety of the six-membered ring A proved to be less reactive than that of the five-membered ring D, but all the reactions were affected significantly by the substitution pattern of the nitrile oxide. 17-Deacetylation of the primary products resulted in aromatization or simultaneous hydroxylation, depending on the base applied for the ring A-fused heterocycles, while retro-Dieckmann-like fragmentation was observed partially or completely for the ring D-fused analogues during 3-deacetylation.

Original languageEnglish
Pages (from-to)76-85
Number of pages10
JournalSteroids
Volume87
DOIs
Publication statusPublished - Sep 2014

Keywords

  • 5α-Androstanes
  • Cycloaddition
  • Isoxazolines
  • Regioselectivity
  • Stereocontrol

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Endocrinology
  • Pharmacology
  • Clinical Biochemistry
  • Organic Chemistry

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