Publications by authors named "Karam Son"

A series of 2-aryl pyridine C-region derivatives of 2-(3-fluoro-4-methylsulfonylaminophenyl)propanamides were investigated as hTRPV1 antagonists. Multiple compounds showed highly potent TRPV1 antagonism toward capsaicin comparable to previous lead 7. Among them, compound 9 demonstrated anti-allodynia in a mouse neuropathic pain model and blocked capsaicin-induced hypothermia in a dose-dependent manner.

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A series of 2-alkyl/alkenyl pyridine C-region derivatives of 2-(3-fluoro-4-methylsulfonylaminophenyl)propanamides were investigated as hTRPV1 antagonists. Multiple compounds showed excellent and stereospecific TRPV1 antagonism with better potency than previous lead 2. Among them, compound 15f demonstrated a strong analgesic profile in a rat neuropathic pain model and blocked capsaicin-induced hypothermia in a dose-dependent manner.

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Some of the fascinating features of voltage-sensing domains (VSDs) in voltage-gated cation channels (VGCCs) are their modular nature and adaptability. Here we examined the VSD sensitivity of different VGCCs to 2 structurally related nontoxin gating modifiers, NH17 and NH29, which stabilize K(v)7.2 potassium channels in the closed and open states, respectively.

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The chiral isomers of the two potent simplified RTX-based vanilloids, compounds 2 and 3, were synthesized employing highly enantioselective PTC alkylation and evaluated as hTRPV1 ligands. The analysis indicated that the R-isomer was the eutomer in binding affinity and functional activity. The agonism of compound 2R was comparable to that of RTX.

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A series of 2-thio pyridine C-region analogues of 2-(3-fluoro-4-methylsulfonylaminophenyl)propanamides were investigated as hTRPV1 antagonists. Among them, compound 24S showed stereospecific and excellent TRPV1 antagonism of capsaicin-induced activation. Further, it demonstrated strong anti-allodynic in a rat neuropathic pain model.

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A series of carbonate analogues of 5'-halogenated RTX have been investigated in order to examine the effect of the carbonate group as a linker and the role of halogens in the reversal of activity from agonism to antagonism for rat and human TRPV1 heterologously expressed in Chinese hamster ovary cells. The carbonate analogues showed similar activities to the corresponding RTX derivatives in rat TRPV1 but lower potency in human TRPV1. 5-Halogenation converted the agonists to partial agonists or full antagonists and the extent of antagonism reflected the order of I>Br>Cl>F, with a somewhat greater extent of antagonism for the derivatives of the 4-amino RTX surrogates compared to the corresponding derivatives of RTX itself.

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The structure activity relationships of 2-oxy pyridine derivatives in the C-region of N-(6-trifluoromethyl-pyridin-3-ylmethyl) 2-(3-fluoro-4-methylsulfonylaminophenyl)propanamides as hTRPV1 antagonists were investigated. The analysis indicated that the lipophilicity of the 2-oxy substituents was critical for potent antagonism and 4 or 5 carbons appeared to be optimal for activity. Multiple compounds proved to have comparable activity to 1, which had been reported as the most potent antagonist for capsaicin activity among the previous series of compounds.

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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.

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The structure-activity relationships of N-(3-acyloxy-2-benzylpropyl)-N'-4-[(methylsulfonylamino)benzyl] thioureas, which represent simplified RTX-based vanilloids, were investigated by varying the distances between the four principal pharmacophores and assessing binding and antagonistic activity on rTRPV1. The analysis indicated that a 3-pivaloyloxy-2-benzylpropyl C-region conferred the best potency in binding affinity and antagonism. The molecular modeling of this best template with the tetrameric homology model of rTRPV1 was performed to identify its binding interactions with the receptor.

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