Synthesis and Biological Evaluation of New 1,2,3‐Triazolyl‐Pyrazolyl‐Quinoline Derivatives as Potential Antimicrobial Agents

Abstract

Abstract A new series of 4‐{1‐phenyl‐4‐[(4‐phenyl‐1,2,3‐triazol‐1‐yl)methyl]pyrazol‐3‐yl}quinoline (7a‐l) have been synthesized by a click reaction of 4‐(4‐(azidomethyl)‐1‐phenyl‐1 H ‐pyrazol‐3‐yl)quinoline (5a‐d) with a substituted ethynylbenzene. The newly synthesized 1,2,3‐triazolyl‐pyrazolyl‐quinoline derivatives were evaluated for biological activity against Escherichia coli (NCIM 2574), Proteus mirabilis (NCIM 2388), (Gram negative strains), Bacillus subtilis (NCIM 2063), Staphylococcus albus (NCIM 2178) (Gram positive strains) and in vitro antifungal activity against Candida albicans (NCIM 3100) and Aspergillus niger (ATCC 504). Five 1,2,3‐triazolyl‐pyrazolyl‐quinoline derivatives, 7d, 7 g, 7 h, 7k and 7 l exhibited good antifungal activity against A. niger with MIC 62.5 μg/mL. The compounds 7 h, 7k and 7 l were further evaluated for ergosterol inhibition assay against A. niger cell sample at 62.5 μg/mL concentration. Upon analysis of the sterol inhibition assay, it was revealed that, the ergosterol biosynthesis has decreased in the fungal samples treated with the 1,2,3‐triazolyl‐pyrazolyl‐quinoline derivatives. Thus antimicrobial activity suggested that, these compounds could aid and assist in the development of lead compounds to treat microbial infections.