Abstract
A series of N-(2-amino-6-trifluoromethylpyridin-3-ylmethyl)-2-(3-fluoro-4- methylsulfonylaminophenyl)propanamides were designed combining previously identified pharmacophoric elements and evaluated as hTRPV1 antagonists. The SAR analysis indicated that specific hydrophobic interactions of the 2-amino substituents in the C-region of the ligand were critical for high hTRPV1 binding potency. In particular, compound 49S was an excellent TRPV1 antagonist (K i(CAP) = 0.2 nM; IC50(pH) = 6.3 nM) and was thus approximately 100- and 20-fold more potent, respectively, than the parent compounds 2 and 3 for capsaicin antagonism. Furthermore, it demonstrated strong analgesic activity in the rat neuropathic model superior to 2 with almost no side effects. Compound 49S antagonized capsaicin induced hypothermia in mice but showed TRPV1-related hyperthermia. The basis for the high potency of 49S compared to 2 is suggested by docking analysis with our hTRPV1 homology model in which the 4-methylpiperidinyl group in the C-region of 49S made additional hydrophobic interactions with the hydrophobic region.
Original language | English |
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Pages (from-to) | 8392-8408 |
Number of pages | 17 |
Journal | Journal of Medicinal Chemistry |
Volume | 55 |
Issue number | 19 |
DOIs | |
State | Published - 11 Oct 2012 |