Synthesis and cytotoxicity on human leukemia cells of furonaphthoquinones isolated from tabebuia plants.

Furonaphthoquinones are promising skeletons for anticancer drug molecules. In particular, methoxylated furonaphthoquinones are characteristic constituents of Tabebuia plants. In this research, we synthesized the furonaphthoquinones by effective one-pot cascade reactions of 3-phenyliodonio-1,2,4-trioxo-1,2,3,4-tetrahydronaphthalenides with 3-butyn-2-ol in the presence of palladium and cuprous catalysts via Sonogashira coupling and intramolecular cyclization. Furthermore, we demonstrated that the synthetic furonaphthoquinones showed moderate cytotoxicity against human leukemia U937 and HL-60 cells. Our work highlights the importance of furonaphthoquinones as antileukemic agents.