Metabolites of proteaceae. Part V. Reflexin and conocarpic acid from Leucospermum reflexium Buek ex Meisner, and the phenol-dienone rearrangement of reflexin and conocarpin

Abstract

Reflexin is obtained from leaves of Leucospermum reflexum Buek ex Meisner by extraction with methanol and is shown to correspond to the methyl ester of the ring-A-opened form of conocarpin, viz. conocarpic acid. Both reflexin and conocarpin undergo phenol–dienone conversion into a dibromo-spiro-cyclohexadienone cyclic ether system on treatment with bromine in water. A model system, 3-(4-hydroxyphenyl)propan-1-ol, reacts in the same manner.