N-Thiolated β-Lactam Antibacterials: Defining the Role of Unsaturation in the C4 Side Chain Original Research Article

N-Methylthio β-lactams represent a novel family of antibacterial agents for methicillin-resistant Staphylococcus aureus (MRSA). The structure–activity functions and mechanism of action of these compounds, although still largely undefined, differ dramatically from those of all previously reported β-lactam antibiotics. Prior work has established that the N-alkylthio moiety is required for antibacterial activity, and that a variety of unsaturated groups can be tolerated at C4 of the lactam ring. This report describes the effect that unsaturation within the C4 substituent has on antibacterial activity of these interesting new N-thiolated β-lactams.