Synthesis and Antibacterial Evaluation of a Novel Series of 2-(1,2-Dihydro-3-oxo-3H-pyrazol-2-yl)benzothiazoles

The 2-(1,2-dihydro-3-oxo-3H-pyrazol-2-yl)benzothiazole scaffold was selected as a central core structure for the discovery of novel antibacterial compounds. A systematic variation of the substituents on the oxo-pyrazole moiety, as well as on the benzo moiety, led to the creation of a small and focused library of benzothiazoles that was subjected to antibacterial screening. In a first round of screening, activity of the compounds against six representative microorganisms was established. For the most potent congeners, MIC values against S. aureus and P. aeruginosa were determined. The structureactivity relationship study clearly revealed that subtle structural variations influence the antibacterial activity to a large extent. The most potent congeners displayed MIC values of 3.30 μM.