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Planta Med 1995; 61(2): 154-157
DOI: 10.1055/s-2006-958037
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© Georg Thieme Verlag Stuttgart · New York

Heteronuclear NMR Studies of the Chromone Alkaloids and Revision of the Structure of Some Piperidino-Chromone Alkaloids

Peter J. Houghton1 , Ibironke M. Osibogun2 , Tibebe Z. Woldemariam1 , Keith Jones3
  • 1Department of Pharmacy, King's College London, Manresa Road, London SW3 6LX, U.K.
  • 2 Department of Pharmacy, University of Lagos, Lagos, Nigeria
  • 3Department of Chemistry, King's College London, Strand London WC2, U.K.
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Publication History

1994

1994

Publication Date:
04 January 2007 (online)

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Abstract

The 13C-NMR spectra of seven chromone alkaloids isolated from Schumanniophyton magnificum have been obtained. Assignment of signals was carried out with the help of heteronuclear coupling experiments and other correlation techniques on the alkaloids and their acyl derivatives. On the basis of the signals observed the structures of the piperidino-alkaloid schumannificine and its N-methyl and anhydro analogues have been revised to that of a piperidone ring linked to the noreugenin via a carbon-carbon bond and a lactol bridge.

Key words

Schumanniophyton magnificum - Rubiaceae - chromone alkaloids - carbon-13 NMR - schumannificine