A large-scale synthesis of the bis-bioreductive drug 1, 4-bis {[2-(dimethylamino) ethyl] amino}-5, 8-dihydroxyanthracene-9, 10-dione bis-N-oxide (AQ4N) has been developed. This six-step synthesis provides AQ4N in 20% overall yield from readily available tetrachlorophthalic anhydride. The key step was a KF–NaF-mediated conversion of 3, 6- dichlorophthalic anhydride to 3, 6-difluorophthalic anhydride, which could be achieved in ...