SYNTHESIS & SCHIFF BASES OF QUINOLINE DERIVATIVES FOR ANTIMICROBIAL ACTIVITIES

Niggula Praveen Kumar*, J. E. Rachel Nivedita, V. Arun Reddy, Togari Manoj Kumar and Gatadi Srikanth

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ABSTRACT

Quinoline derivatives are a class of compounds with a wide range of biological activities, including antimicrobial
properties. The development of novel antimicrobial agents is essential to combat the growing threat of antibiotic
resistance. In this study, we synthesized a series of quinoline derivatives and their Schiff bases, and evaluated their
antimicrobial activities against a panel of Gram-positive and Gram-negative bacteria, as well as fungi. The
quinoline derivatives were synthesized through the reaction of quinoline-2-carbaldehyde with various amines,
including aniline, p-anisidine, and o-phenylenediamine. The resulting Schiff bases were characterized by FTIR,
NMR, and mass spectroscopy. The antimicrobial activities of the synthesized compounds were evaluated using the
disc diffusion method and minimum inhibitory concentration (MIC) assays. The results show that the quinoline
derivatives and their Schiff bases exhibited significant antimicrobial activity against all tested microorganisms,
with MIC values ranging from 0.5 to 64 μg/mL. The Schiff bases showed improved antimicrobial activity
compared to their parent quinoline derivatives, with some exhibiting MIC values as low as 0.5 μg/mL. The most
active compounds were found to be those containing the p-anisidine and o-phenylenediamine moieties. The results
of this study demonstrate the potential of quinoline derivatives and their Schiff bases as novel antimicrobial agents.
The synthesized compounds may be useful in the development of new antibiotics to combat the growing threat of
antibiotic resistance. Further studies are needed to investigate the mechanism of action of these compounds and to
evaluate their safety and efficacy in animal models.

Keywords: Schff bases, Quinoline derivatives, QSAR, Antimicrobial drugs.