Intramolecular sensitization within steroids: Excited-state interaction of C-17 alpha and beta carbon-bromine bonds with a C-6 carbonyl group


Li W., Torun L. , Morrison H.

CANADIAN JOURNAL OF CHEMISTRY, vol.81, no.6, pp.660-668, 2003 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 81 Issue: 6
  • Publication Date: 2003
  • Doi Number: 10.1139/v03-055
  • Title of Journal : CANADIAN JOURNAL OF CHEMISTRY
  • Page Numbers: pp.660-668

Abstract

The synthesis, photochemistry, and photophysics of 17alpha-bromo-3alpha-(triphenylsilyloxy)-5alpha-androstan-6-one (1) and 17beta-bromo-3beta-(triphenylsilyloxy)-5alpha-androstan-6-one (2) have been studied in aqueous tetrahydrofuran. The 17alpha-bromo isomer gives evidence (reduced phi(f), tau(1), and phi(isc) for the ketone) for interaction between the ketone and C-Br moieties in the excited singlet state. Some photodehalogenation is also observed upon excitation of the ketone chromophore. This interaction seems to be absent or minimal for the 17beta-bromo isomer.