Synthesis, characterization, and antimicrobial evaluation of carbostyril derivatives of 1H-pyrazole

A new series of 12 derivatives of 4-pyrazolyl-N-arylquinoline-2,5-dione (4a–l) were synthesized by one pot base catalyzed cyclocondensation reaction of 1-aryl-5-chloro-3-methyl-1H-pyrazole-4-carbaldehyde (1a–c), Meldrum’s acid (2) and 3-arylamino-5,5-disubstitutedcyclohex-2-enone (3a–d). All the compounds were characterized by elemental analysis, FT-IR, 1H NMR and 13C NMR spectral data and were screened, against six bacterial pathogens, namely Bacillus subtilis, Clostridium tetani, Streptococcus pneumoniae, Salmonella typhi, Vibrio cholerae, Escherichia coli and antifungal activity, against two fungal pathogens Aspergillus fumigatus and Candida albicans, using broth microdilution MIC (minimum inhibitory concentration) method. Some of the compounds were found to be equipotent or more potent than commercial drugs, against most of the employed strains, as evident from the screening data.