Fused fluoroquinolones: synthesis and 1H and 19F NMR studies

New derivatives of fused fluoroquinolones bearing five aromatic rings have been obtained. The 19F NMR spectra of these pentacyclic fluoroquinolones demonstrate unusual through space 1H–19F and 19F–19F spin–spin interactions with coupling constants 6J(F, H)=2.0–3.0 Hz, 7J(F, F)=3.5–4.0 Hz and 9J(F, H)=3.0–3.5 Hz. Relative reactivities of fluorine atoms in pentacyclic fluoroquinolones in the amino-defluorination reactions are also different relative to bi- and tricyclic fluoroquinolones.