K-Opioid receptor agonist-1

Compound 5a is a potent and brain-penetrant κ-opioid receptor agonist (Ki = 0.25 nM, EC50 = 2 nM) with a brain/plasma ratio of 0.50-0.65. It demonstrates anti-inflammatory activity in preclinical models of arachidonic acid- and oxazolidinone-induced dermatitis, supporting research in neuropharmacology and inflammatory skin disease.