Synthesis and antimicrobial activity of 2-phenyl-3-{1-cyclopropyl-6-fluoro-7-[4-methylpiperazin-1-yl]-4-quinolone}carboxamido-3-thiazolidin-4-ones

The title compounds VIa – j have been prepared from the lead molecule 7-chloro-1-cyclopropyl-6-fluoro-4-oxo-1,4-dihydroquinoline-3-carboxylic acid I. The lead molecule was converted to hydrazide III via acid chloride II, which on reaction with different substituted aromatic aldehydes a – j afforded Schiff base, and on further structural variation of the Schiff base furnished the final compoundsVIa – j (Scheme I). The synthesized compounds were tested for their antibacterial and antifungal activity (MIC) in vitro against two Gram-positive bacteria, S. aureus and S. pyogenes, and two Gram-negative bacteria E. coli and P. aeruginosa, and fungi C. albicans, A. niger, and A. clavatus, taking gentamycin, ampicillin, chloramphenicol, ciprofloxacin, norfloxacin, nystatin, and griseofulvin as standard drugs. All the synthesized compounds have been established by elemental analysis amd IR and NMR spectral data.