Synthesis, characterization and biological evaluation of a series of levofloxacin carboxamide analogues

Abstract

In present work an attempt was made to synthesize various analogues of levofloxacin by introducing new functionality at carboxylic group position via nucleophilic substitution reaction. For this purpose the carboxylic group at C-6 was esterified and later subjected to nucleophilic attack at the carbonyl carbon by various aromatic amines. Structure of the analogues was confirmed by different techniques i.e. IR, 1H NMR and mass spectrometry. The antibacterial activity of the derivatives was also assessed and compared with the parent against a series of Gram-positive and Gram-negative bacteria. A synergistic as well as antagonistic behavior was observed in these derivatives. Additionally unlike levofloxacin, the derivatives were also found to modulate oxidative burst response of phagocytes exhibiting moderate to significant inhibitory activity.