Modulation of Drug Resistance in Staphylococcus aureus with Coumarin Derivatives

Scheme 1

Synthesis of alkyl-, acetyl-, and nitro-coumarin derivatives. Reagents and conditions: (a) acetic anhydride, pyridine, rt, ultrasound irradiation; (b) allyl bromide, geranyl bromide, or prenyl bromide, K₂CO₃, acetonitrile, and reflux; (c) HNO₃/AcOH, 0–5°C for 30 min and then 90 min at rt.