Studies on quinones. Part 35: Access to antiprotozoal active euryfurylquinones and hydroquinones

(+)-Euryfuran adds regiospecifically to activated monosubstituted 1,4-benzoquinones under mild conditions to give the corresponding Michael adducts which, depending on the quinone substituent, undergo in situ redox reactions to the respective euryfurylbenzoquinones. One of these Michael adducts undergoes a facile stereoselective cyclisation under oxidant conditions to afford a naphthofuro[4,3-c]benzopyran derivative. The in vitro activities of the obtained euryfurylquinones and hydroquinones against Leishmania amazonensis are described.