Fluoroalkyl α side chain containing 3,4-diamino-cyclobutenediones as potent and orally bioavailable CXCR2–CXCR1 dual antagonists

A series of potent and orally bioavailable 3,4-diaminocyclobutenediones with various fluoroalkyl groups as α side chain were prepared and found to show significant improvements in the binding affinities towards both CXCR2 and CXCR1 receptors.