Ebenaceae extractives. Part 9. New naphthoquinones and binaphthylquinones from macassar ebony

Abstract

In addition to macassar II (1) and its methyl ether, macassar III, the heartwood of Diospyros celebica contains diomelquinone A (2), the o-naphthoquinone (3), celebaquinone (8), isocelebaquinone (21), and diosindigo B (10) and its dihydro-derivative (13). These extractives appear to be related biogenetically to the dihydric methoxynaphthols (15) and (27). Two other products, diosindigos B₁(17) and B₂(18), which contain ethoxy groups, are artefacts formed during the extraction procedure.