Flavonoids of Tephrosia procumbens—revised structure for praecansone A and conformation of praecansone B
- 1 January 1987
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in Journal of the Chemical Society, Perkin Transactions 1
- No. 12,p. 2723-2727
- https://doi.org/10.1039/p19870002723
Abstract
Two rotenoids (rotenone and sumatrol), a flavanone (obovatin), a β-diketone (praecansone B), and its isomeric methyl ether (praecansone A) have been isolated from the chloroform extract of roots of Tephrosia procumbens. Furthermore, an unusual flavonol (7-ethoxy-3,3′,4′-trihydroxyflavone; fisetin 7-ethyl ether) and an isoflavone (7,4′-dihydroxy-3′-methoxyisoflavone) have been isolated from an ethyl acetate fraction of the alcoholic extract of the roots. The structures of all the compounds were established spectroscopically. The structure of praecansone A has been revised as (3) on the basis of 13C and 1H n.m.r. data, and confirmed by an n.O.e. experiment. The possible conformations of praecansone B in CDCl3 are discussed on the basis of 1H n.m.r. data and D2O-exchange studies.This publication has 3 references indexed in Scilit:
- Flavonoids from the seeds of Lonchocarpus costaricensisPhytochemistry, 1985
- 8-Substituted flavonoids and 3′-substituted 7-oxygenated chalcones from Tephrosia purpureaJournal of the Chemical Society, Perkin Transactions 1, 1981
- The extractives of Millettia dura (Dunn)Tetrahedron, 1967