Tectonaquinones A, B and C: three new naphthoquinone derivatives from the heartwood of .

Chemical investigation of the chloroform extract of heartwood of L. f. led to the isolation of three new naphthoquinone derivatives, tectonaquinones A (), B () and C (), along with six known compounds: barleriaquinone-I (), tectoquinone (), tecomaquinone I (), lapachol (), obtusifolin () and 2-hydroxy-3-methyl anthraquinone (). The structures of the new compounds were elucidated by spectroscopic methods including 2 D NMR experiments. Tectonaquinone B is the first natural compound that has a hexa-cyclic dinaphthofuran-dione scaffold. Tectonaquinone C has a bicyclic acetal motif that is unusual in nature.