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Published on: September 20, 2016
Highly Potent and Selective New Diphenethylamines Interacting with the κ-Opioid Receptor: Synthesis, Pharmacology,
Filippo Erli1, Elena Guerrieri1, Tanila Ben Haddou1
1Department of Pharmaceutical Chemistry, Institute of Pharmacy and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck , Innrain 80-82, 6020 Innsbruck, Austria.
Abstract:
We previously reported on a series of small molecules targeting the κ-opioid (KOP) receptor featuring a diphenethylamine scaffold and showed the promise of these ligands as effective analgesics with reduced liability for adverse effects. This study expands the structure-activity relationships on our original series by presenting several modifications in the lead compounds 1 (HS665) and 2 (HS666). A library of new diphenethylamines was designed, synthesized, and pharmacologically evaluated. In comparison with 1 and 2, the KOP receptor affinity, selectivity, and agonist activity were modulated by introducing bulkier N-substituents, a 2-fluoro substitution, and additional hydroxyl groups at positions 3' and 4'. Several analogues showed subnanomolar affinity and excellent KOP receptor selectivity acting as full or partial agonists, and one as an antagonist. The new diphenethylamines displayed antinociceptive efficacies with increased potencies than U50,488, 1 and 2 in the writhing assay and without inducing motor dysfunction after sc administration in mice.
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