8-Amino-7-(aryl/hetaryl)fluoroquinolones. An emerging set of synthetic antibacterial agents

Abstract This study reports the synthesis of seven new 8-amino-7-(aryl/hetaryl)fluoroquinolones and their antibacterial activity against 10 bacteria associated with microbial infections and foodborne illnesses. These fluoroquinolones are prepared via the reactions of selected aryl(hetaryl)boronic acids with ethyl-7chloro-6-fluoro-8-nitroquinolone-3-carboxylate, under Suzuki–Miyaura cross-coupling conditions. Nitro group reduction of the latter resulted in the corresponding 8-aminoquinolone-3-esters which upon hydrolysis formed the respective 8-amino-7-(aryl/hetaryl)-quinolone-3-carboxylic acids. The latter compounds were tested against selected Gram-negative bacteria ( Escherichia coli , Salmonella typhimurium , Pseudomonas aeruginosa , Acinetobacter baumannii , and Klebsiella pneumonia ) and Gram-positive bacteria ( Enterococcus feacalis , Listeria monocytogenes , Streptococcus agalactiae , Staphylococcus epidermidis , and Staphylococcus aureus ). The tested fluoroquinolones showed a significant antimicrobial activity against most of the tested bacterial strains. The antimicrobial activity of some of the tested compounds were comparable to or higher than a wide range of standard antibiotics including ampicillin, ciprofloxacin, and imipenem. The results highlight the new synthesized 8-amino-7-(aryl/hetaryl)fluroquinolones as promising candidates for new antimicrobial drugs to treat bacterial infections. This study highlights that the newly synthetic 8-amino-7-(aryl/hetaryl)fluroquinolones are promising candidates for new antimicrobial drugs to treat human diseases including foodborne illnesses.