Discovery of the highly potent fluoroquinolone-based benzothiazolyl-4-thiazolidinone hybrids as antibacterials.

A new series of fluoroquinolone-based benzothiazolyl-4-thiazolidinone hybrids has been yielded via sulfated tungstate-promoted highly accelerated N-formylation at a piperazine residue of ciprofloxacin and norfloxacin entities. The formylated fluoroquinolone moieties were then coupled with substituted 2-aminobenzothiazoles, which were generated from their respective para-substituted amines to form corresponding Schiff base intermediates. The Schiff bases were then treated with thioglycolic acid to equip a new class of 4-thiazolidinones to be analyzed for their antibacterial effects against two Gram-positive (Staphylococcus aureus and Bacillus subtilis) and two Gram-negative (Escherichia coli and Pseudomonas aeruginosa) bacterial strains and were found highly potent with lowest Minimum inhibitory concentrations (MIC), 1-2 μg/mL, that is, more potent than control drugs ciprofloxacin (3.12-6.25 μg/mL). Initial outcomes provided for these novel molecular systems will aid researchers to design and develop new antibacterial drugs. The structural assignments of the new products were done on the basis of FT-IR, (1) H NMR and (13) C NMR spectroscopy, and elemental analysis.