DHFR-IN-8 (compound 6r) is a dihydrofolate reductase (DHFR) inhibitor that affects purine and thymidylate biosynthesis in cell proliferation and growth. DHFR-IN-8 inhibits methicillin-resistant Staphylococcus aureus (MRSA) ATCC 43300 ( IC 50 =15.6 ng/mL) in mouse models of systemic infection and thigh infection.