Synthesis, Characterization and Biological Activity of a Series of Carboxamide Derivatives of Ofloxacin

The present study was designed to help develop new agents with better antimicrobial profiles. Specifically, we focused on modification of the basic structure of ofloxacin by introducing new functionality at its C3 position. For this purpose, the carboxylic group at the C3 position of ofloxacin was replaced by an amide group through an ester aminolysis reaction. The structure of these derivatives was established by various analytical techniques i.e., IR, H-1-NMR, C-13-NMR CHNS elemental analysis and mass spectrometry. The antibacterial activity of ofloxacin and its derivatives against ten different Gram-positive and Gram-negative microorganisms was studied using a disk susceptibility method. These compounds were further tested for their activity against various fungi and compared to ofloxacin. The synthesized compounds showed diverse antimicrobial profiles. Among them, a few compounds possessed a comparable or better activity in comparison to the reference drug.