Synthesis and In‐vitro Antibacterial Activities of N‐substituted Piperazinyl Quinolones

Abstract

A series of N-substituted piperazinyl quinolones were prepared and evaluated for in-vitro antibacterial activity. Compounds having phenacyl group attached to the piperazine ring were as potent as norfloxacin, ciprofloxacin and enoxacin. The oximes were almost as potent as the corresponding ketones against staphylococci but less active against Gram-negative bacteria. Some oximes were found to be more active than norfloxacin and enoxacin against Gram-positive organisms. In general, the O-benzyloxime derivatives had lower antibacterial activity than reference compounds. However, compounds having a 4-nitro group in the benzyl moiety of O-benzyloxime derivatives had antistaphylococcal activity greater than norfloxacin, ciprofloxacin and enoxacin. Generally, ciprofloxacin derivatives were more active than norfloxacin or enoxacin derivatives.