SYNTHESIS OF CYTOTOXIC FURONAPHTHOQUINONES - REGIOSPECIFIC SYNTHESIS OF DIODANTUNEZONE AND 2-ETHYLFURONAPHTHOQUINONES

Diodantunezone was first isolated horn Lantana achyrantifolia (Verbena ceae) and originally assigned as 8-hydroxy-4,9-dihydronaphtho[2,3-b]fu ran la but its structure was later revised to 5-hydroxy-4,9-dihydronap htho[2,3-b]furan-4,9-dione 2a. The regiospecific synthesis of diodantu nezone 2a and its methyl ether, 5-methoxy-4,9-dihydronaphtho[2,3-b]fur an-4,9-dione 2b, is described. The preparation of two 2-ethylfuronapht hoquinones 14a and 14b is also described. Ail four quinones were shown to possess cytotoxic activity against three cell lines(1.3-17.4 mu mo l dm(-3)). (C) 1997 Elsevier Science Ltd.