Synthesis, Molecular Modeling and In vitro Antimicrobial Evaluation of New Quinolin-4yl-hydrazones

Antibacterial drugs are the mainstay for the treatment of serious bacterial infections, such as tuberculosis. Twenty new quinolinyl hydrazones were prepared and evaluated for antimicrobial activity against two Gram-positive and two Gram-negative bacteria and antimycobacterial activity against Mycobacterium tuberculosis (H37Rv). In view of the amphiphilic nature of quinalinyl hydrazones, and their ability to penetrate the bacterial cell wall, we sought to synthesize and evaluate them for antimicrobial activity. The new quinolinyl hydrazones with 7-chloro-substitution on quinoline ring and various aryl and heterocyclic substituted hydrazone at 4th position of quinoline ring were prepared and evaluated for antimicrobial activity. Among the series, the two com-pounds 4e, 4k with 3-chromone and 5-methylthiphene heterocyclic systems exhibited significant antitubercular activity with MIC of 0.81 and 0.90 µg/ml respectively and the potency is comparable to that of the standard, isoniazid with MIC of 0.78 µg/ml. In antimicrobial screen-ing, compounds 4h & 4l with 3-pyridyl and 2-furyl rings on hydrazone nitrogen exhibited significant activity against the two Gram+ve and Gram-ve bacterial strains with MIC values in the range of 16-24 µg/ml. Based on these results, the lead compounds appear to possess the potential antibacterial potential against Mycobacerium and other bacteria.