Design, Synthesis, and In Vitro Antibacterial Activities of Propylene-tethered Gatifloxacin-isatin Hybrids

A series of novel mono-/bis-isatin-gatifloxacin hybrids 3a-f and 4a-f tethered through propylene were designed, synthesized, and evaluated for their in vitro antibacterial activities against representative Gram-positive and Gram-negative pathogens. The results indicated that all mono-isatin-gatifloxacin hybrids exhibited considerable antibacterial activities with minimum inhibitory concentration ranging from 0.06 to 4g/mL against the majority of the tested strains. In particular, the mono-isatin-gatifloxacin hybrid 3b was found as potent as the parent gatifloxacin against Gram-positive organisms and could act as a starting point for further optimization.