CONVENTIONAL AND MICROWAVE ASSISTED SYNTHESIS OF NOVEL QUINOLINE DERIVATIVES AND THEIR ANTIMICROBIAL AND ANTIOXIDANT POTENTIAL

摘要

Objective: To synthesize novel quinoline derivatives by conventional and microwave methods and to characterize them by using IR, 1H NMR and mass spectra and to screen the molecules for antioxidant and antimicrobial activities. Methods: Novel series of 5-(quinoline-4-yl)-1,3,4-thiadiazol-2-amine derivatives (AR-6 to AR-10) have been synthesized by cyclisation of aniline, substituted aldehyde and pyruvic acid which yields substituted quinoline carboxylic acid (AR-1 to AR-5) followed by reaction with phosphorous oxy trichloride and thiosemicarbazide. Results: The synthesized compounds were characterized by IR, 1H NMR and mass spectra and they were screened for their antimicrobial and antioxidant activities. Antimicrobial study of these compounds against Gram+ve and Gram-ve organisms such as Bacillus subtillus, Escherichia coli, Staphylococcus aureus and antifungal activity against Aspergillus. showed good activity Compounds AR-1, AR-3 exhibited broad spectrum antimicrobial activity at a concentration of 5μg/ml when compared to standard ciprofloxacin (1μg/ml). Compounds AR-10 (22.38μg/ml), AR-3 (24.97 μg/ml), AR-8(38.12μg/ml) showed comparable antioxidant activity compared to standard ascorbic acid(12.18μg/ml). Conclusions: AR-1, AR -3 exhibited broad spectrum antimicrobial activity and AR-10,AR-3,AR-8 showed comparable antioxidant activity. The mechanism by which this molecules exhibit antioxidant activity is still under study