Isofl avonoid derivatives from Lophira alata stem heartwood

摘要

Six isofl avonoid derivatives among which three are new have been isolated from the stem heartwood of Lophira alata. The structures were elucidated from spectroscopic and chemical evidences. Two have unusual carbon skeletons, possibly resulting from a variant of isofl avonoid biogenesis. The two compounds form the first members of a new subclass of fl avonoid compounds which we call "isobifl avonoids". The presence of these isofl avonoid compounds in this plant of the Ochnaceae family has important chemotaxonomic implications since it modifies the botanic distribution of isofl avonoid compounds in non-leguminous plants.