Synthesis of cytotoxic furonaphthoquinones: Regiospecific synthesis of diodantunezone and 2-ethylfuronaphthoquinones

Article abstract of DOI:10.1016/S0040-4020(97)00030-6

Diodantunezone was first isolated from Lantana achyrantifolia (Verbenaceae) and originally assigned as 8-hydroxy-4,9-dihydronaphtho[2,3-b]furan-4,9-dione 1a but its structure was later revised to 5-hydroxy-4,9 dihydronaphtho[2,3-b]furan-4,9-dione 2a. The regiospecific synthesis of diodantunezone 2a and its methyl ether, 5-methoxy-4,9-dihydronaphtho[2,3-b]furan-4,9-dione 2b, is described. The preparation of two 2-ethylfuronaphthoquinones 14a and 14b is also described. All four quinones were shown to possess cytotoxic activity against three cell lines (1.3-17.4 μmol dm^-3).