- Receptor activity and conformational analysis of 5′-halogenated resiniferatoxin analogs as TRPV1 ligands
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A series of 5′-halogenated resiniferatoxin analogs have been investigated in order to examine the effect of halogenation in the A-region on their binding and the functional pattern of agonism/antagonism for rat TRPV1 heterologously expressed in Chinese hamster ovary cells. Halogenation at the 5-position in the A-region of RTX and of 4-amino RTX shifted the agonism of parent compounds toward antagonism. The extent of antagonism was greater as the size of the halogen increased (I > Br > Cl > F) while the binding affinities were similar, as previously observed for our potent agonists. In this series, 5-bromo-4-amino RTX (39) showed very potent antagonism with K i (ant) = 2.81 nM, which was thus 4.5-fold more potent than 5′-iodo RTX, previously reported as a potent TRPV1 antagonist. Molecular modeling analyses with selected agonists and the corresponding halogenated antagonists revealed a striking conformational difference. The 3-methoxy of the A-region in the agonists remained free to interact with the receptor whereas in the case of the antagonists, the compounds assumed a bent conformation, permitting the 3-methoxy to instead form an internal hydrogen bond with the C4-hydroxyl of the diterpene.
- Lim, Kwang Su,Kang, Dong Wook,Kim, Yong Soo,Kim, Myeong Seop,Park, Seul-Gi,Choi, Sun,Pearce, Larry V.,Blumberg, Peter M.,Lee, Jeewoo
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p. 299 - 302
(2011/02/27)
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- Halogenation of 4-hydroxy/amino-3-methoxyphenyl acetamide TRPV1 agonists showed enhanced antagonism to capsaicin
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As an extension of our analysis of the effect of halogenation on thiourea TRPV1 agonists, we have now modified selected 4-hydroxy(or 4-amino)-3- methoxyphenyl acetamide TRPV1 agonists by 5- or 6-halogenation on the aromatic A-region and evaluated them for potency for TRPV1 binding and regulation and for their pattern of agonism/antagonism (efficacy). Halogenation shifted the functional activity at TRPV1 toward antagonism with a greater extent of antagonism as the size of the halogen increased (I > Br > Cl), as previously observed for the thiourea series. The extent of antagonism was greater for halogenation at the 5-position than at the 6-position, in contrast to SAR for the thiourea series. In this series, compounds 55 and 75 showed the most potent antagonism, with Ki (ant) = 2.77 and 2.19 nM, respectively, on rTRPV1 expressed in Chinese hamster ovary cells. The compounds were thus ca. 40-60-fold more potent than 6′-iodononivamide.
- Kang, Dong Wook,Kim, Yong Soo,Lim, Kwang Su,Kim, Myeong Seop,Pearce, Larry V.,Pavlyukovets, Vladimir A.,Tao, Andy K.,Lang-Kuhs, Krystle A.,Blumberg, Peter M.,Lee, Jeewoo
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experimental part
p. 8092 - 8105
(2011/01/13)
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- PYRROLIDINE DERIVATIVES AS TRYPTASE INHIBITORS
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Compounds of a certain formula 1 in which M, B1, B2, R2, K1 and K2 have the meanings indicated in the description are novel effective tryptase inhibitors.
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Page/Page column 20
(2010/02/06)
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- Biosynthetic Studies of ω-Cycloheptyl Fatty Acids in Alicyclobacillus cycloheptanicus. Formation of Cycloheptanecarboxylic Acid from Phenylacetic Acid
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The formation of the structurally novel, mono-substituted cycloheptane ring in ω-cycloheptyl fatty acids in Alicyclobacillus cycloheptanicus (formerly Bacillus cycloheptanicus) has been examined. Feeding experiments with 13C- and 2H-labeled intermediates demonstrated that cycloheptanecarboxylic acid (3), probably as its CoA thioester, is the starter unit for ω-cycloheptyl fatty acid biosynthesis. Analysis of the resultant labeling pattern from a feeding experiment with [U-13C6]-glucose suggested a shikimate pathway origin of 3 via aromatic amino acids. [1,2-13C2]Phenylacetic acid (6) was efficiently metabolized into the 3-derived moiety in a manner reminiscent of the seven-membered ring Pseudomonas metabolite thiotropocin. The fates of the aromatic and benzylic hydrogens of 6 were determined; these dictated various boundary conditions for the biosynthetic pathway from 6 to 3. Taken together with the results from feeding experiments with postulated cycloheptenylcarboxylate biosynthetic intermediates, the data lead us to propose a pathway which involves an oxidative ring-expansion of 6 to a hydroxynorcaradiene intermediate followed by a series of double bond reductions and dehydrations to the saturated 3.
- Moore, Bradley S.,Walker, Kevin,Tornus, Ingo,Handa, Sandeep,Poralla, Karl,Floss, Heinz G.
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p. 2173 - 2185
(2007/10/03)
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- Synthesis of dihalophenylacetic acids using aromatic nucleophilic substitution strategy
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A simple synthetic strategy to dihalophenylacetic acids and specifically 3,5-difluorophenylacetic acid an important pharmaceutical intermediate was developed. The aromatic nucleophilic substitution of dihalofluorobenzenes using the anion of ethyl cyanoacetate yielded ethyl dihalophenylcyanoacetates. The basic decarboxylation of the ethyl dihalophenylcyanoacetates produced targeted dihalophenylacetic acids.
- Kowalczyk, Bruce A.
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p. 1411 - 1414
(2007/10/03)
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