RESUMO
Facilitating activation, or delaying inactivation, of the native Kv7 channel reduces neuronal excitability, which may be beneficial in controlling spontaneous electrical activity during epileptic seizures. In an effort to identify a compound with such properties, the structure-activity relationship (SAR) and in vitro ADME for a series of heterocyclic Kv7.2-7.5 channel openers was explored. PF-05020182 (2) demonstrated suitable properties for further testing in vivo where it dose-dependently decreased the number of animals exhibiting full tonic extension convulsions in response to corneal stimulation in the maximal electroshock (MES) assay. In addition, PF-05020182 (2) significantly inhibited convulsions in the MES assay at doses tested, consistent with in vitro activity measure. The physiochemical properties, in vitro and in vivo activities of PF-05020182 (2) support further development as an adjunctive treatment of refractory epilepsy.
Assuntos
Descoberta de Drogas , Epilepsia/tratamento farmacológico , Ativação do Canal Iônico/efeitos dos fármacos , Canal de Potássio KCNQ2/metabolismo , Piperidinas/farmacologia , Pirimidinas/farmacologia , Animais , Linhagem Celular , Relação Dose-Resposta a Droga , Eletrochoque , Humanos , Canal de Potássio KCNQ2/agonistas , Microssomos/efeitos dos fármacos , Estrutura Molecular , Piperidinas/administração & dosagem , Piperidinas/química , Pirimidinas/administração & dosagem , Pirimidinas/química , Ratos , Relação Estrutura-AtividadeRESUMO
Herein we report the identification of (+)-N-(2-((1H-pyrazol-1-yl)methyl)-3-((1R,3r,5S)-6'-fluoro-8-azaspiro[bicyclo[3.2.1]octane-3,1'-isochroman]-8-yl)propyl)-N-[(3)H]-methylacetamide {[(3)H]PF-7191 [(+)-11]} as a promising radiotracer for the nociceptin opioid peptide (NOP) receptor. (+)-11 demonstrated high NOP binding affinity (Ki = 0.1 nM), excellent selectivity over other opioid receptors (>1000×) and good brain permeability in rats (C(b,u)/C(p,u) = 0.29). Subsequent characterization of [(3)H](+)-11 showed a high level of specific binding and a brain bio-distribution pattern consistent with known NOP receptor expression. Furthermore, the in vivo brain binding of [(3)H](+)-11 in rats was inhibited by a selective NOP receptor antagonist in a dose-responsive manner. This overall favorable profile indicated that [(3)H](+)-11 is a robust radiotracer for pre-clinical in vivo receptor occupancy (RO) measurements and a possible substrate for carbon-11 labeling for positron emission tomography (PET) imaging in higher species.
Assuntos
Encéfalo/metabolismo , Desenho de Fármacos , Peptídeos Opioides/metabolismo , Receptores Opioides/metabolismo , Trítio/metabolismo , Animais , Relação Dose-Resposta a Droga , Avaliação Pré-Clínica de Medicamentos/métodos , Peptídeos Opioides/química , Ligação Proteica/fisiologia , Ratos , Trítio/química , Receptor de NociceptinaRESUMO
We describe a novel series of inhibitors of the type 1 glycine transporter (GlyT1) as an approach to relieving the glutamatergic deficit that is thought to underlie schizophrenia. Synthesis and SAR follow-up of a series of octahydro-cyclopenta[c]pyrrole derivatives afforded potent in vitro inhibition of GlyT1 as well as in vivo activity in elevating CSF glycine. We also found that a 3-O(c-pentyl), 4-F substituent may serve as a surrogate for the widely used 3-trifluoromethoxy group, suggesting its application as an isostere for future medicinal chemistry studies.
Assuntos
Ciclopentanos/química , Proteínas da Membrana Plasmática de Transporte de Glicina/antagonistas & inibidores , Pirróis/química , Animais , Linhagem Celular , Ciclopentanos/farmacologia , Cães , Proteínas da Membrana Plasmática de Transporte de Glicina/fisiologia , Humanos , Microssomos/efeitos dos fármacos , Microssomos/fisiologia , Pirróis/farmacologiaRESUMO
We previously observed a cutaneous type IV immune response in nonhuman primates (NHP) with the mGlu5 negative allosteric modulator (NAM) 7. To determine if this adverse event was chemotype- or mechanism-based, we evaluated a distinct series of mGlu5 NAMs. Increasing the sp3 character of high-throughput screening hit 40 afforded a novel morpholinopyrimidone mGlu5 NAM series. Its prototype, (R)-6-neopentyl-2-(pyridin-2-ylmethoxy)-6,7-dihydropyrimido[2,1-c][1,4]oxazin-4(9H)-one (PF-06462894, 8), possessed favorable properties and a predicted low clinical dose (2 mg twice daily). Compound 8 did not show any evidence of immune activation in a mouse drug allergy model. Additionally, plasma samples from toxicology studies confirmed that 8 did not form any reactive metabolites. However, 8 caused the identical microscopic skin lesions in NHPs found with 7, albeit with lower severity. Holistically, this work supports the hypothesis that this unique toxicity may be mechanism-based although additional work is required to confirm this and determine clinical relevance.
Assuntos
Regulação Alostérica/efeitos dos fármacos , Compostos Heterocíclicos com 3 Anéis/farmacologia , Compostos Heterocíclicos com 3 Anéis/farmacocinética , Piridinas/farmacologia , Piridinas/farmacocinética , Receptor de Glutamato Metabotrópico 5/antagonistas & inibidores , Receptor de Glutamato Metabotrópico 5/metabolismo , Animais , Feminino , Células HEK293 , Compostos Heterocíclicos com 3 Anéis/efeitos adversos , Compostos Heterocíclicos com 3 Anéis/química , Humanos , Masculino , Simulação de Acoplamento Molecular , Piridinas/efeitos adversos , Piridinas/química , Ratos , Ratos Sprague-Dawley , Relação Estrutura-AtividadeRESUMO
Through fragment-based drug design focused on engaging the active site of IRAK4 and leveraging three-dimensional topology in a ligand-efficient manner, a micromolar hit identified from a screen of a Pfizer fragment library was optimized to afford IRAK4 inhibitors with nanomolar potency in cellular assays. The medicinal chemistry effort featured the judicious placement of lipophilicity, informed by co-crystal structures with IRAK4 and optimization of ADME properties to deliver clinical candidate PF-06650833 (compound 40). This compound displays a 5-unit increase in lipophilic efficiency from the fragment hit, excellent kinase selectivity, and pharmacokinetic properties suitable for oral administration.
Assuntos
Descoberta de Drogas , Quinases Associadas a Receptores de Interleucina-1/antagonistas & inibidores , Isoquinolinas/farmacologia , Inibidores de Proteínas Quinases/farmacologia , Administração Oral , Relação Dose-Resposta a Droga , Humanos , Quinases Associadas a Receptores de Interleucina-1/metabolismo , Isoquinolinas/administração & dosagem , Isoquinolinas/química , Lactamas , Modelos Moleculares , Estrutura Molecular , Inibidores de Proteínas Quinases/administração & dosagem , Inibidores de Proteínas Quinases/química , Relação Estrutura-AtividadeRESUMO
The palladium - catalyzed aminocarbonylation of aryl tosylates with amines is reported. Suitable conditions were identified by high throughput reaction screening and then further optimized. The substrate scope of the reaction with respect to the aryl tosylate component and the amine component are reported. Competitive aminolysis of the aryl tosylates to afford the amine toluenesulfonamides and the phenol was not observed.
Assuntos
Aminas/química , Fenilacetatos/síntese química , Compostos de Tosil/química , Catálise , Estrutura Molecular , Paládio/química , Fenilacetatos/químicaRESUMO
We report that the stereochemical outcome of the conjugate addition of organocopper reagents to bicyclic α,ß-unsaturated lactams derived from pyroglutaminol is determined by the nature of the aminal group. Bicyclic α,ß-unsaturated lactams in which the aminal is derived from a ketone have been found to afford products of syn conjugate addition. By contrast, bicyclic α,ß-unsaturated lactams in which the aminal is derived from an aldehyde afford products of anti conjugate addition. These remarkably different results obtained from very similar starting materials are unexpected.
Assuntos
Cobre/química , Lactamas/química , Aldeídos/química , Cetonas/química , Estrutura Molecular , Pirróis/química , EstereoisomerismoRESUMO
The synthesis and structure-activity relationships of a series of 6-phenyl-2-aminopyridines that potently and selectively inhibit the neuronal isoform of nitric oxide synthase (nNOS) are described. Compound 14bi from this series exhibits potent in vivo activity in harmaline-induced cGMP formation in rat cerebellum, a functional model of nNOS inhibition, and in the PCP-induced hypermotility model in the rat. These results suggest that 14bi may be a useful reagent for evaluating potential therapeutic applications of nNOS inhibitors in the central nervous system.
Assuntos
Aminopiridinas/síntese química , Óxido Nítrico Sintase/antagonistas & inibidores , Tetra-Hidronaftalenos/síntese química , Aminopiridinas/química , Aminopiridinas/farmacologia , Animais , Cerebelo/efeitos dos fármacos , Cerebelo/metabolismo , GMP Cíclico/biossíntese , Masculino , Atividade Motora/efeitos dos fármacos , Óxido Nítrico Sintase/química , Óxido Nítrico Sintase Tipo I , Ratos , Ratos Sprague-Dawley , Relação Estrutura-Atividade , Tetra-Hidronaftalenos/química , Tetra-Hidronaftalenos/farmacologiaRESUMO
A novel series of pyrazolopyrazines is herein disclosed as mGluR5 negative allosteric modulators (NAMs). Starting from a high-throughput screen (HTS) hit (1), a systematic structure-activity relationship (SAR) study was conducted with a specific focus on balancing pharmacological potency with physicochemical and pharmacokinetic (PK) properties. This effort led to the discovery of 1-methyl-3-(4-methylpyridin-3-yl)-6-(pyridin-2-ylmethoxy)-1H-pyrazolo[3,4-b]pyrazine (PF470, 14) as a highly potent, selective, and orally bioavailable mGluR5 NAM. Compound 14 demonstrated robust efficacy in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-rendered Parkinsonian nonhuman primate model of l-DOPA-induced dyskinesia (PD-LID). However, the progression of 14 to the clinic was terminated because of a potentially mechanism-mediated finding consistent with a delayed-type immune-mediated type IV hypersensitivity in a 90-day NHP regulatory toxicology study.
Assuntos
Pirazinas/síntese química , Pirazóis/síntese química , Receptor de Glutamato Metabotrópico 5/metabolismo , 1-Metil-4-Fenil-1,2,3,6-Tetra-Hidropiridina , Administração Oral , Regulação Alostérica , Animais , Antiparkinsonianos/efeitos adversos , Disponibilidade Biológica , Permeabilidade da Membrana Celular , Cães , Discinesia Induzida por Medicamentos/tratamento farmacológico , Células HEK293 , Humanos , Hipersensibilidade Tardia/induzido quimicamente , Levodopa/efeitos adversos , Macaca fascicularis , Células Madin Darby de Rim Canino , Masculino , Microssomos Hepáticos/metabolismo , Modelos Moleculares , Doença de Parkinson/tratamento farmacológico , Doença de Parkinson/etiologia , Doença de Parkinson/fisiopatologia , Pirazinas/farmacologia , Pirazinas/toxicidade , Pirazóis/farmacologia , Pirazóis/toxicidade , Ensaio Radioligante , Ratos , Ratos Sprague-Dawley , Relação Estrutura-AtividadeRESUMO
INTRODUCTION: Fatty acid amide hydrolase (FAAH) is responsible for the enzymatic degradation of the fatty acid amide family of signaling lipids, including the endogenous cannabinoid (endocannabinoid) anandamide. The involvement of the endocannabinoid system in pain and other nervous system disorders has made FAAH an attractive target for drug development. Companion molecular imaging probes are needed, however, to assess FAAH inhibition in the nervous system in vivo. We report here the synthesis and in vivo evaluation of [(18)F]PF-9811, a novel PET ligand for non-invasive imaging of FAAH in the brain. METHODS: The potency and selectivity of unlabeled PF-9811 were determined by activity-based protein profiling (ABPP) both in vitro and in vivo. [(18)F]PF-9811 was synthesized in a 3-step, one-pot reaction sequence, followed by HPLC purification. Biological evaluation was performed by biodistribution and dynamic PET imaging studies in male rats. The specificity of [(18)F]PF-9811 uptake was evaluated by pre-administration of PF-04457845, a potent and selective FAAH inhibitor, 1h prior to radiotracer injection. RESULTS: Biodistribution studies show good uptake (SUV~0.8 at 90 min) of [(18)F]PF-9811 in rat brain, with significant reduction of the radiotracer in all brain regions (37%-73% at 90 min) in blocking experiments. Dynamic PET imaging experiments in rat confirmed the heterogeneous uptake of [(18)F]PF-9811 in brain regions with high FAAH enzymatic activity, as well as statistically significant reductions in signal following pre-administration of the blocking compound PF-04457845. CONCLUSIONS: [(18)F]PF-9811 is a promising PET imaging agent for FAAH. Biodistribution and PET imaging experiments show that the tracer has good uptake in brain, regional heterogeneity, and specific binding as determined by blocking experiments with the highly potent and selective FAAH inhibitor, PF-04457845.
Assuntos
Amidoidrolases/metabolismo , Encéfalo/enzimologia , Piperidinas/síntese química , Tomografia por Emissão de Pósitrons/métodos , Piridazinas/síntese química , Animais , Encéfalo/diagnóstico por imagem , Técnicas de Química Sintética , Ligantes , Masculino , Piperidinas/química , Piperidinas/farmacocinética , Piridazinas/química , Piridazinas/farmacocinética , Radioquímica , RatosRESUMO
The synthesis of NPTS, 6, a potent inhibitor of the type 1 glycine transporter (GlyT1) is described, as well as preparation of 6 in optically active and tritiated form for use as a radioligand for affinity displacement assay of GlyT1.