Synthesis, characterization and biological activity of some new carbostyril bearing 1H-pyrazole moiety

In this study, 16 new 4-pyrazolyl-N-arylquinoline-2,5-dione 4 have been synthesized by the multicomponent reaction of pyrazole-4-carbaldehyde 1, Meldrum's acid 2 and 3-aryl-5,5-disubstitutedcyclohex-2-enone 3. The structures of compounds 4 were established by the combined use of H-1 NMR, C-13 NMR, FT-IR and mass spectra. All the 16 compounds were tested in vitro for their bacterial and fungal activity against a list of human pathogens, namely, Bacillus subtilis, Clostridium tetani, Streptococcus pneumoniae, Salmonella typhi, Vibrio cholerae, Escherichia coli, Aspergillus fumigatus and Candida albicans, using broth microdilution MIC (minimum inhibitory concentration) method. Some of the compounds were found to be the most effective analogs against the tested bacterial and fungal strains.