Synthesis and antimicrobial activity of novel fluorine containing 4-(substituted-2-hydroxybenzoyl)-1H-pyrazoles and pyrazolyl benzo[d]oxazoles.

Abstract A series of fluorine containing 4-(substituted-2-hydroxybenzoyl) pyrazoles and pyrazolyl benzo[ d ]oxazoles were synthesized and evaluated for their antibacterial activity against Staphylococcus aureus , Escherichia coli , Pseudomonas aeruginosa and Bacillus subtilis and antifungal activity against Candida albicans . The antibacterial activities were expressed as the minimum inhibitory concentration (MIC 50 ) in μg/ml. The compounds 1-(3,4-difluorophenyl)-4-(5-fluoro-2-hydroxybenzoyl)-1 H -pyrazole ( 4b ), oxime derivatives such as 1-(3,4-difluorophenyl)-1 H -pyrazol-4-yl)(2-hydroxy-4-methylphenyl)methanone oxime ( 5b ) and (5-chloro-2-hydroxyphenyl)(1-(3,4-difluorophenyl)-1 H -pyrazol-4-yl)methanone oxime ( 5e ) exhibited promising activities against tested bacterial strains. Except compound 1-(3,4-difluorophenyl)-4-(2-hydroxybenzoyl)-1 H -pyrazole ( 4d ), none of the other compounds showed promising antifungal activity.