Synthesis and antimicrobial evaluation of 3-substituted-imine-6-hydroxy-benzofuran derivatives

A series of 3-substituted-imine-6-hydroxy-benzofuran derivatives were chemically synthesized and biologically evaluated as antibacterial and antifungal agents against Candida albicans, Escherichia coli, Staphylococcus aureus, methicillin-resistant Staphylococcus aureus and Bacillus subtilis. Most compounds showed a selective antibacterial activity to gram-positive bacteria and four compounds revealed great antibacterial activities against methicillin-resistant Staphylococcus aureus comparing to the positive control (Ceftazidime) with MIC₈₀ = 12.5–25 μg/mL. Structure-activity relationship studies demonstrated that the free hydroxy group at the C-6 position is essential to the antibacterial activity, and the aromatic imine fragment at the C-3 position also greatly increases antibacterial activity.