Synthesis and evaluation of N-alkyl-9-aminoacridines with antibacterial activity.

Abstract A series of 9-alkylaminoacridines were synthesized and evaluated for activity against two strains of methicillin-resistant and one strain of methicillin-sensitive Staphylococcus aureus . Results are presented that show a clear structure activity relationship between the N -alkyl chain length and antibacterial activity with peak MIC 99 values of 2–3 μM for alkyl chains ranging from 10 to 14 carbons in length. Although prior work has linked the function of acridine-based compounds to intercalation and topoisomerase inhibition, the present results show that 9-alkylaminoacridines likely function as amphiphilic membrane-active disruptors potentially in a similar manner as quaternary ammonium antimicrobials.