Biological evaluation of isothiazoloquinolones containing aromatic heterocycles at the 7-position: In vitro activity of a series of potent antibacterial agents that are effective against methicillin-resistant Staphylococcus aureus

We synthesized a diverse series of 9H-isothiazolo[5,4-b]quinoline-3,4-diones containing heteroaromatic groups at the 7-position via palladium-catalyzed cross-coupling. Many of these compounds demonstrated potent antistaphylococcal activity (MICs ⩽2 μg/mL) against a multi-drug-resistant strain (ATCC 700699) and low cytotoxic activity (CC50 > 100 μM) against the human cell line Hep2 (laryngeal carcinoma).

Graphical abstractSeveral of the reported analogues demonstrate strong in vitro antistaphylococcal activity, particularly against MRSA, and low cytotoxicity.Figure optionsDownload full-size imageDownload as PowerPoint slide