7-Piperazinylquinolones with methylene-bridged nitrofuran scaffold as new antibacterial agents

Quinolone class of antibacterial agents has considerable attention to find new useful antibacterial agents. Therefore, a series of N-substituted piperazinylquinolones bearing (5-nitrofuran-2-yl)methyl moiety were synthesized and evaluated against a variety of bacteria. The methylene-bridged nitrofuran functionality has been recently used in oxazolidinone class of antibacterial agents containing piperazinyl moiety by introducing ranbezolid as a 5-nitrofuran analog of eperzolid. The results of antibacterial evaluation revealed that the influence of (5-nitrofuran-2-yl) attachment to the 7-piperazinylquinolones against different bacterial species depends on the type of substituents at the N-1 and C-8 positions. Better results were obtained with ethyl at N-1 and CF at C-8 in the term of activity against Bacillus subtilis and E. coli. While, the optimum activity against Staphylococcus aureus, Pseudomonas aeruginosa, and Klebsiella pneumonia was entailed by a molecule possessing cyclopropyl at N-1 and CH at C-8.