Synthesis of an ethyl 6-amino-3,5-difluorosalicylate derivative by sequential regioselective directed ortho- metalation; a practical synthesis of 4',5-Diamino-3',6,8-trifluoroflavone, a potent antitumor agent

Article abstract of DOI:10.1055/s-1997-1379

The multigram scale synthesis of 4',5-diamino-3'6,8-trifluoroflavone, a potent antitumor agent, is described in which regioselective introduction of a carbonyl group into the ortho-position to the amide group of 2-[2,4-difluoro-5-(pivaloylamino)phenyoxy]tetrahydropyran is achieved by using sequential direct ortho-metalations as the key step.