New Flavonoid and Coumarin Derivatives of Uvaria afzelii

Article abstract of DOI:10.1021/jo00328a017

Three new compounds, 2'-hydroxydemethoxymatteucinol (6), 2-hydroxy-7,8-dehydrograndiflorone (7), and uvafzelic acid (9) have been identified in extracts of Uvaria afzelii.Their structures were determined mainly from interpretation of the 13C NMR spectral data. 7 was unstable and was rapidly converted to emorydone (8).Four other known compounds, coumarin (3), syncarpic acid (4), demethoxymatteucinol (5), and emorydone (8), were also identified along with the previously reported constituents, vafzelin (1) and uvafzelin (2).The stabilities of 1, 7, and 8 under neutral,acidic, and basic conditions were studied by HPLC.