Design, Synthesis, and Antibacterial Evaluation of Propylene-tethered 8-Methoxyl Ciprofloxacin-isatin Hybrids

A series of 8-methoxyl ciprofloxacin (8-OMe CPFX)-isatin hybrids 3a–f and 4a–f tethered through propylene were designed, synthesized, and examined for their in vitro antibacterial activities against a panel of Gram-positive and Gram-negative pathogens including drug-resistant bacteria. All the synthesized hybrids (minimum inhibitory concentration: ≤0.03–64 μg/mL) exhibited considerable activities against the tested strains, especially against the Gram-negative pathogens. Among them, hybrid 3b was no inferior to the parent 8-OMe CPFX that could act as a starting point for further optimization.