| Abstract
| - A stepwise chemical modification from human neurokinin-3 receptor (hNK-3R)-selectiveantagonists to potent and combined hNK-3R and hNK-2R antagonists using the same2-phenylquinoline template is described. Docking studies with 3-D models of the hNK-3 andhNK-2 receptors were used to drive the chemical design and speed up the identification ofpotent and combined antagonsits at both receptors. (S)-(+)-N-(1-Cyclohexylethyl)-3-[(4-morpholin-4-yl)piperidin-1-yl]methyl-2-phenylquinoline-4-carboxamide (compound 25, SB-400238: hNK-3R binding affinity, Ki = 0.8 nM; hNK-2R binding affinity, Ki = 0.8 nM) emergedas the best example in this approach. Further studies led to the identification of (S)-(+)-N-(1,2,2-trimethylpropyl)-3-[(4-piperidin-1-yl)piperidin-1-yl]methyl-2-phenylquinoline-4-carboxamide (compound 28, SB-414240: hNK-3R binding affinity, Ki = 193 nM; hNK-2R bindingaffinity, Ki = 1.0 nM) as the first hNK-2R-selective antagonist belonging to the 2-phenylquinoline chemical class. Since some members of this chemical series showed a significant bindingaffinity for the human μ-opioid receptor (hMOR), docking studies were also conducted on a3-D model of the hMOR, resulting in the identification of a viable chemical strategy to avoidany significant μ-opioid component. Compounds 25 and 28 are therefore suitable pharmacological tools in the tachykinin area to elucidate further the pathophysiological role of NK-3 andNK-2 receptors and the therapeutic potential of selective NK-2 (28) or combined NK-3 andNK-2 (25) receptor antagonists.
|
