RESUMO
The pharmacology of the M5 muscarinic acetylcholine receptor (mAChR) is the least understood of the five mAChR subtypes due to a historic lack of selective small molecule tools. To address this shortcoming, we have continued the optimization effort around the prototypical M5 positive allosteric modulator (PAM) ML380 and have discovered and optimized a new series of M5 PAMs based on a chiral N-(indanyl)piperidine amide core with robust SAR, human and rat M5 PAM EC50 values <100 nM and rat brain/plasma Kp values of â¼0.40. Interestingly, unlike M1 and M4 PAMs with unprecedented mAChR subtype selectivity, this series of M5 PAMs displayed varying degrees of PAM activity at the other two natively Gq-coupled mAChRs, M1 and M3, yet were inactive at M2 and M4.
Assuntos
Colinérgicos/farmacologia , Regulação Alostérica , Amidas/química , Animais , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Colinérgicos/síntese química , Colinérgicos/química , Colinérgicos/farmacocinética , Descoberta de Drogas , Humanos , Masculino , Microssomos Hepáticos/efeitos dos fármacos , Microssomos Hepáticos/metabolismo , Estrutura Molecular , Piperidinas/química , Ratos Sprague-Dawley , Receptores Muscarínicos/metabolismo , Relação Estrutura-AtividadeRESUMO
The inward rectifier potassium (Kir) channel Kir7.1 (KCNJ13) has recently emerged as a key regulator of melanocortin signaling in the brain, electrolyte homeostasis in the eye, and uterine muscle contractility during pregnancy. The pharmacological tools available for exploring the physiology and therapeutic potential of Kir7.1 have been limited to relatively weak and nonselective small-molecule inhibitors. Here, we report the discovery in a fluorescence-based high-throughput screen of a novel Kir7.1 channel inhibitor, VU714. Site-directed mutagenesis of pore-lining amino acid residues identified glutamate 149 and alanine 150 as essential determinants of VU714 activity. Lead optimization with medicinal chemistry generated ML418, which exhibits sub-micromolar activity (IC50 = 310 nM) and superior selectivity over other Kir channels (at least 17-fold selective over Kir1.1, Kir2.1, Kir2.2, Kir2.3, Kir3.1/3.2, and Kir4.1) except for Kir6.2/SUR1 (equally potent). Evaluation in the EuroFins Lead Profiling panel of 64 GPCRs, ion-channels, and transporters for off-target activity of ML418 revealed a relatively clean ancillary pharmacology. While ML418 exhibited low CLHEP in human microsomes which could be modulated with lipophilicity adjustments, it showed high CLHEP in rat microsomes regardless of lipophilicity. A subsequent in vivo PK study of ML418 by intraperitoneal (IP) administration (30 mg/kg dosage) revealed a suitable PK profile (Cmax = 0.20 µM and Tmax = 3 h) and favorable CNS distribution (mouse brain/plasma Kp of 10.9 to support in vivo studies. ML418, which represents the current state-of-the-art in Kir7.1 inhibitors, should be useful for exploring the physiology of Kir7.1 in vitro and in vivo.
Assuntos
Modelos Moleculares , Bloqueadores dos Canais de Potássio/química , Bloqueadores dos Canais de Potássio/farmacologia , Canais de Potássio Corretores do Fluxo de Internalização/antagonistas & inibidores , Canais de Potássio Corretores do Fluxo de Internalização/metabolismo , Animais , Relação Dose-Resposta a Droga , Células HEK293 , Humanos , Potenciais da Membrana/efeitos dos fármacos , Potenciais da Membrana/genética , Mutagênese Sítio-Dirigida , Mutação/genética , Técnicas de Patch-Clamp , Potássio/metabolismo , Canais de Potássio Corretores do Fluxo de Internalização/química , Canais de Potássio Corretores do Fluxo de Internalização/genética , Relação Estrutura-Atividade , Fatores de Tempo , TransfecçãoRESUMO
Stereoselective palladium-catalyzed Kumada-Corriu reactions of functionalized alkenyl halides and a variety of Grignard reagents, including those bearing ß-hydrogen atoms and sensitive functional groups, can be carried out at room temperature using a new combination of reagents.
Assuntos
Alcenos/química , Alcenos/síntese química , Hidrocarbonetos Halogenados/química , Paládio/química , Catálise , Técnicas de Química Combinatória , Estrutura Molecular , Estereoisomerismo , TemperaturaRESUMO
Unexpected losses in stereochemistry from Stille reactions involving Z-alkenyl halides have been shown to be ligand dependent. A new set of reaction conditions has been developed that, in most cases, leads to highly stereoselective cross-couplings under mild conditions, along with improved yields.
RESUMO
The ligands associated with various Pd catalysts play a crucial role in determining the stereochemistry of cross-couplings between boronic acids and Z-alkenyl halides. A ligand on palladium has been found that leads to the desired products under mild conditions and in high yields that, in most cases, retain their Z-olefin geometry.
RESUMO
Copper iodide has been shown to be an effective cocatalyst for the olefin cross-metathesis reaction. In particular, it has both a catalyst stabilizing effect due to iodide ion, as well as copper(I)-based phosphine-scavenging properties that apply to use of the Grubbs-2 catalyst. A variety of Michael acceptors and olefinic partners can be cross-coupled under mild conditions in refluxing diethyl ether that avoid chlorinated solvents. This effect has also been applied to chemistry in water at room temperature using the new surfactant TPGS-750-M.
Assuntos
Alcenos/química , Cobre/química , Iodetos/química , Catálise , CinéticaRESUMO
New technology for palladium-catalyzed cross-couplings between B2pin2 and aryl bromides leading to arylboronates is described. Micellar catalysis serves to enable borylations to take place in water as the only medium at ambient temperatures.
RESUMO
The first examples of unsymmetrical olefin cross-metathesis reactions in water, involving water-insoluble substrates, at room temperature and using commercially available catalysts are reported. The key to success is to include small percentages of the nonionic, vitamin E-based amphiphile "PTS". The nanometer micelles formed accommodate water-insoluble substrates, along with a readily available Ru-based metathesis catalyst. Reactions proceed at ambient temperatures with high efficiency and very high E-selectivity, and products are easily isolated.