8-Substituted flavonoids and 3′-substituted 7-oxygenated chalcones from Tephrosia purpurea

Abstract

The isolation and characterisation of ten unusual and closely related flavonoids from the roots of T. purpurea are reported. Three of these compounds are new natural products and they all contain an isopentenyl derived unit attached to C-8 (in the flavones) or the corresponding C-3′(in the chalcones), suggesting that they are derived from a common biosynthetic precursor. The 1H and 13C n.m.r. spectra of use in structure elucidation are reported.