Hybrid molecules between benzenesulfonamides and active antimicrobial benzo[d]isothiazol-3-ones

Novel hybrid molecules between benzenesulfonamides and active antimicrobial 2-amino-benzo[d]isothiazol-3-ones were synthesized and characterised and their in vitro antimicrobial activity was evaluated by the minimal inhibitory concentration (MIC). The compounds exhibit moderate antibacterial properties against Gram-positive bacteria (MIC 6–100 μg ml−1) such as several bacilli, staphylococci and streptococci, including methicillin-resistant Staphylococcus aureus and Staphylococcus epidermidis strains, while no inhibition of Gram-negative Escherichia coli is detected up to the concentration of 100 μg ml−1. Synergistic inhibitory activity occurs when sulfanilamides 4a and 4c are tested in combination with trimethoprim against S. aureus. Concerning antifungal properties, only compound 4c is able to inhibit the growth of Saccharomyces cerevisiae and Cryptococcus neoformans yeasts and several dermatophytes. Structure–activity relationships are discussed.

Graphical abstractNovel benzo[d]isothiazol-3-one benzenesulfonamides exhibit moderate antibacterial properties against Gram-positive bacteria such as bacilli, staphylococci and streptococci, including methicillin-resistant strains. The structure–activity relationships and the action mechanism are discussed.Figure optionsDownload full-size imageDownload as PowerPoint slide