The chemistry of the Euphorbiaceae. VIII. New flavones from Ricinocarpus stylosus

Abstract

The structures of four new naturally occurring flavonoid pigments have been determined. They have been shown to be 5-hydroxy-3,7,8,3',4'-pentamethoxyflavone, 5,3'-dihydroxy-3,7,8,4'-tetramethoxyflavone, 5,4'-dihydroxy-3,7,8-trimethoxyflavone and 5,3',5'-trihydroxy-3,7,4'-trimethoxyflavone. The N.M.R. correlations of these and some related flavonols are discussed.