The structure of wightianone, the pigment of a clathrate from Calophyllum wightianum

Abstract

From the heartwood of Calophyllum wightianum T. Anders has been isolated, in small quantities, a clathrate composed of four molecules of a pigment, wightianone, to one of palmitic acid. Other fatty acids are present in small amounts. Wightianone is shown to be identical with zeyloxanthonone and to have the structure (1){7,9-dihydroxy-4,4,8-tris(3-methylbut-2-enyl)-1,2-dihydroxanthene-3-dione}. The isomeric structure (2) for the pigment was rejected on the basis of the aromatic solvent-induced shifts and because of biosynthetic considerations, i.e., the occurrence of gem-dialkylation in resorcinol and phloroglucinol but not in quinol nuclei.