Extractives from Guttiferae. Part VII. The isolation and structure of seven xanthones from Calophyllum scriblitifolium Henderson and Wyatt-Smith

Abstract

Two xanthones, 6-desoxyjacareubin and osajaxanthone, have been isolated from the heartwood of Calophyllum scriblitifolium Henderson and Wyatt-Smith. Methylation of a crude extract led to the isolation of the methyl ethers of another five hydroxyxanthones, 2-(3,3-dimethylallyl)-1,3,5-trihydroxyxanthone, 2-(3,3-dimethylallyl)-1,3,7 trihydroxyxanthone, 2-(3,3-dimethylallyl)-1,3,5,6-tetrahydroxyxanthone, jacareubin, and 1,5,6-trihydroxyxanthone. The biogenetic implication of the co-occurrence of these metabolites is discussed. The value of solvent shifts in assigning the structures of pyranoxanthones is assessed.