... Structure-activity relationship studies showed that quinolones having a five or six-membered heterocyclic ring at the C-7 position show good antibacterial activities [2 ... Chemistry. ... 1.61 (t, 3H, J = 7.1, СН2СН3), 2.48 (s, ЗН, NCH3), 3.01 (q, IH, I = 10.7, C5.-H), 3.51 (q, Ш, J = 10.7, Cs ...