Synthesis of polyfluorinated aminoquinolines via nitroquinolines

Transformation of 14 quinolines polyfluorinated in the benzene moiety was investigated in nitration systems: a mixture of HNO₃ and H₂SO₄, NaNO₃ in H₂SO₄, NO₂BF₃OH in sulfolane, or NaNO₃ in oleum. 5-Nitro- and/or 8-nitro derivatives formed if positions 5 or 8 were unoccupied in the starting compounds. Otherwise, nitro products were not detectable, and the initial compounds were oxidized. In some cases, F atoms at the ortho position relative to the nitro group were substituted thus affording hydroxynitroquinolines. Polyfluorinated 2-chloroquinolines were nitrated more easily than were quinolines not containing a substituent at position 2. Thus, a method is proposed for reduction of nitroquinolines to aminoquinolines that are not available via other approaches.