Ortho-hydrodefluorination of polyfluorinated 4-acetamidobiphenyls and synthesis of polyfluorinated 6-phenylquinolines

Polyfluorinated 4-acetamido- and 4,4′-bis(acetamido)biphenyl were reduced in the Zn–NiCl2–2,2′-bipyridine–aq. DMF system to give their for the first time synthesized less fluorinated analogs containing one or two unsubstituted position ortho to the acetamido group. By involving ortho-unsubstituted 4-acetamido- or 4-aminopolyfluorobiphenyls in the Skraup synthesis, new polyfluorinated 6-phenylquinolines and 6,6′-biquinoline were obtained.