RESUMEN
Acetylcholine (ACh) in cortical neural circuits mediates how selective attention is sustained in the presence of distractors and how flexible cognition adjusts to changing task demands. The cognitive domains of attention and cognitive flexibility might be differentially supported by the M1 muscarinic acetylcholine receptor (mAChR) subtype. Understanding how M1 mAChR mechanisms support these cognitive subdomains is of highest importance for advancing novel drug treatments for conditions with altered attention and reduced cognitive control including Alzheimer's disease or schizophrenia. Here, we tested this question by assessing how the subtype-selective M1 mAChR positive allosteric modulator (PAM) VU0453595 affects visual search and flexible reward learning in nonhuman primates. We found that allosteric potentiation of M1 mAChRs enhanced flexible learning performance by improving extradimensional set shifting, reducing latent inhibition from previously experienced distractors and reducing response perseveration in the absence of adverse side effects. These procognitive effects occurred in the absence of apparent changes of attentional performance during visual search. In contrast, nonselective ACh modulation using the acetylcholinesterase inhibitor (AChEI) donepezil improved attention during visual search at doses that did not alter cognitive flexibility and that already triggered gastrointestinal cholinergic side effects. These findings illustrate that M1 mAChR positive allosteric modulation enhances cognitive flexibility without affecting attentional filtering of distraction, consistent with M1 activity boosting the effective salience of relevant over irrelevant objects specifically during learning. These results suggest that M1 PAMs are versatile compounds for enhancing cognitive flexibility in disorders spanning schizophrenia and Alzheimer's diseases.
Asunto(s)
Acetilcolinesterasa , Enfermedad de Alzheimer , Animales , Regulación Alostérica/fisiología , Colinérgicos/farmacología , Acetilcolina/farmacología , Cognición , Enfermedad de Alzheimer/tratamiento farmacológico , Primates , Receptor Muscarínico M1RESUMEN
This Letter describes our ongoing effort to improve the clearance of selective M5 antagonists. Herein, we report the replacement of the previously disclosed piperidine amide (4, disclosed in Part 1) with a pyrrolidine amide core. Several compounds within this series provided good potency, subtype selectivity, and low to moderate clearance profiles. Interestingly, the left-hand side SAR for this series diverged from our earlier efforts.
Asunto(s)
Amidas , Pirrolidinas , Amidas/farmacología , Pirrolidinas/farmacología , Cinética , Antagonistas MuscarínicosRESUMEN
The lack of potent and selective tool compounds with pharmaceutically favorable properties limits the in vivo understanding of muscarinic acetylcholine receptor subtype 5 (M5) biology. Previously, we presented a highly potent and selective M5 antagonist VU6019650 with a suboptimal clearance profile as our second-generation tool compound. Herein, we disclose our ongoing efforts to generate next-generation M5 antagonists with improved clearance profiles. A mix and match approach between VU6019650 (lead) and VU0500325 (HTS hit) generated a piperidine amide-based novel M5 antagonist series. Several analogs within this series, including 29f, provided good on-target potency with improved clearance profiles, though room for improvement remains.
Asunto(s)
Amidas , Receptores Muscarínicos , Amidas/farmacología , Cinética , Piperidinas/farmacologíaRESUMEN
Recent clinical and preclinical studies suggest that selective activators of the M4 muscarinic acetylcholine receptor have potential as a novel treatment for schizophrenia. M4 activation inhibits striatal dopamine release by mobilizing endocannabinoids, providing a mechanism for local effects on dopamine signaling in the striatum but not in extrastriatal areas. G protein-coupled receptors (GPCRs) typically induce endocannabinoid release through activation of Gαq/11-type G proteins whereas M4 transduction occurs through Gαi/o-type G proteins. We now report that the ability of M4 to inhibit dopamine release and induce antipsychotic-like effects in animal models is dependent on co-activation of the Gαq/11-coupled mGlu1 subtype of metabotropic glutamate (mGlu) receptor. This is especially interesting in light of recent findings that multiple loss of function single nucleotide polymorphisms (SNPs) in the human gene encoding mGlu1 (GRM1) are associated with schizophrenia, and points to GRM1/mGlu1 as a gene within the "druggable genome" that could be targeted for the treatment of schizophrenia. Herein, we report that potentiation of mGlu1 signaling following thalamo-striatal stimulation is sufficient to inhibit striatal dopamine release, and that a novel mGlu1 positive allosteric modulator (PAM) exerts robust antipsychotic-like effects through an endocannabinoid-dependent mechanism. However, unlike M4, mGlu1 does not directly inhibit dopamine D1 receptor signaling and does not reduce motivational responding. Taken together, these findings highlight a novel mechanism of cross talk between mGlu1 and M4 and demonstrate that highly selective mGlu1 PAMs may provide a novel strategy for the treatment of positive symptoms associated with schizophrenia.
Asunto(s)
Regulación Alostérica/efectos de los fármacos , Antipsicóticos/metabolismo , Receptor Muscarínico M4/metabolismo , Receptores de Glutamato Metabotrópico/metabolismo , Animales , Ácido Glutámico/metabolismo , Ratones , Ratones Endogámicos C57BLRESUMEN
Behavioral assays in the mouse can show marked differences between male and female animals of a given genotype. These differences identified in such preclinical studies may have important clinical implications. We recently made a mouse model with impaired presynaptic inhibition through Gßγ-SNARE signaling. Here, we examine the role of sexual dimorphism in the severity of the phenotypes of this model, the SNAP25Δ3 mouse. In males, we already reported that SNAP25Δ3 homozygotes demonstrated phenotypes in motor coordination, nociception, spatial memory and stress processing. We now report that while minimal sexually dimorphic effects were observed for the nociceptive, motor or memory phenotypes, large differences were observed in the stress-induced hyperthermia paradigm, with male SNAP25Δ3 homozygotes exhibiting an increase in body temperature subsequent to handling relative to wild-type littermates, while no such genotype-dependent effect was observed in females. This suggests sexually dimorphic mechanisms of Gßγ-SNARE signaling for stress processing or thermoregulation within the mouse. Second, we examined the effects of heterozygosity with respect to the SNAP25Δ3 mutation. Heterozygote SNAP25Δ3 animals were tested alongside homozygote and wild-type littermates in all of the aforementioned paradigms and displayed phenotypes similar to wild-type animals or an intermediate state. From this, we conclude that the SNAP25Δ3 mutation does not behave in an autosomal dominant manner, but rather displays incomplete dominance for many phenotypes.
Asunto(s)
Hipertermia , Caracteres Sexuales , Animales , Modelos Animales de Enfermedad , Exocitosis , Femenino , Masculino , Ratones , Memoria EspacialRESUMEN
Obsessive-compulsive disorder (OCD) is a chronic, disabling condition with inadequate treatment options that leave most patients with substantial residual symptoms. Structural, neurochemical, and behavioral findings point to a significant role for basal ganglia circuits and for the glutamate system in OCD. Genetic linkage and association studies in OCD point to SLC1A1, which encodes the neuronal glutamate/aspartate/cysteine transporter excitatory amino acid transporter 3 (EAAT3)/excitatory amino acid transporter 1 (EAAC1). However, no previous studies have investigated EAAT3 in basal ganglia circuits or in relation to OCD-related behavior. Here, we report a model of Slc1a1 loss based on an excisable STOP cassette that yields successful ablation of EAAT3 expression and function. Using amphetamine as a probe, we found that EAAT3 loss prevents expected increases in (i) locomotor activity, (ii) stereotypy, and (iii) immediate early gene induction in the dorsal striatum following amphetamine administration. Further, Slc1a1-STOP mice showed diminished grooming in an SKF-38393 challenge experiment, a pharmacologic model of OCD-like grooming behavior. This reduced grooming is accompanied by reduced dopamine D1 receptor binding in the dorsal striatum of Slc1a1-STOP mice. Slc1a1-STOP mice also exhibit reduced extracellular dopamine concentrations in the dorsal striatum both at baseline and following amphetamine challenge. Viral-mediated restoration of Slc1a1/EAAT3 expression in the midbrain but not in the striatum results in partial rescue of amphetamine-induced locomotion and stereotypy in Slc1a1-STOP mice, consistent with an impact of EAAT3 loss on presynaptic dopaminergic function. Collectively, these findings indicate that the most consistently associated OCD candidate gene impacts basal ganglia-dependent repetitive behaviors.
Asunto(s)
Ganglios Basales/fisiología , Transportador 3 de Aminoácidos Excitadores/genética , Actividad Motora/genética , Trastorno Obsesivo Compulsivo/genética , Trastorno Obsesivo Compulsivo/fisiopatología , Anfetaminas/farmacología , Animales , Línea Celular , Estimulantes del Sistema Nervioso Central/farmacología , Dopamina/metabolismo , Ácido Glutámico/metabolismo , Aseo Animal/fisiología , Aprendizaje por Laberinto/fisiología , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Actividad Motora/fisiología , Receptores de Dopamina D1/metabolismo , Reflejo de Sobresalto/fisiologíaRESUMEN
This letter describes the further chemical optimization of VU0424238 (auglurant), an mGlu5 NAM clinical candidate that failed in non-human primate (NHP) 28â¯day toxicology due to accumulation of a species-specific aldehyde oxidase (AO) metabolite of the pyrimidine head group. Here, we excised the pyrimidine moiety, identified the minimum pharmacophore, and then developed a new series of saturated ether head groups that ablated any AO contribution to metabolism. Putative back-up compounds in this novel series provided increased sp3 character, uniform CYP450-mediated metabolism across species, good functional potency and high CNS penetration. Key to the optimization was a combination of matrix and iterative libraries that allowed rapid surveillance of multiple domains of the allosteric ligand.
Asunto(s)
Descubrimiento de Drogas , Ácidos Picolínicos/farmacología , Receptor del Glutamato Metabotropico 5/antagonistas & inhibidores , Regulación Alostérica/efectos de los fármacos , Animales , Relación Dosis-Respuesta a Droga , Humanos , Ligandos , Estructura Molecular , Ácidos Picolínicos/síntesis química , Ácidos Picolínicos/química , Ratas , Receptor del Glutamato Metabotropico 5/metabolismo , Relación Estructura-ActividadRESUMEN
This letter describes progress towards an M4 PAM preclinical candidate that resulted in the discovery of VU6005806/AZN-00016130. While the thieno[2,3-c]pyridazine core has been a consistent feature of key M4 PAMs, no work had previously been reported with respect to alternate functionality at the C3 position of the pyridazine ring. Here, we detail new chemistry and analogs that explored this region, and quickly led to VU6005806/AZN-00016130, which was profiled as a putative candidate. While, the ß-amino carboxamide moiety engendered solubility limited absorption in higher species precluding advancement (or requiring extensive pharmaceutical sciences formulation), VU6005806/AZN-00016130 represents a new, high quality preclinical in vivo probe.
Asunto(s)
Regulación Alostérica/inmunología , Receptor Muscarínico M4/inmunología , Estructura Molecular , Relación Estructura-ActividadRESUMEN
This letter describes the first account of the chemical optimization (SAR and DMPK profiling) of a new series of mGlu4 positive allosteric modulators (PAMs), leading to the identification of VU0652957 (VU2957, Valiglurax), a compound profiled as a preclinical development candidate. Here, we detail the challenges faced in allosteric modulator programs (e.g., steep SAR, as well as subtle structural changes affecting overall physiochemical/DMPK properties and CNS penetration).
Asunto(s)
Descubrimiento de Drogas , Compuestos Heterocíclicos con 2 Anillos/farmacología , Isoquinolinas/farmacología , Proteína Quinasa de Distrofia Miotónica/antagonistas & inhibidores , Receptores de Glutamato Metabotrópico/metabolismo , Regulación Alostérica/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Compuestos Heterocíclicos con 2 Anillos/química , Humanos , Isoquinolinas/química , Estructura Molecular , Proteína Quinasa de Distrofia Miotónica/metabolismo , Relación Estructura-ActividadRESUMEN
This letter describes progress towards an M4 PAM preclinical candidate inspired by an unexpected aldehyde oxidase (AO) metabolite of a novel, CNS penetrant thieno[2,3-c]pyridine core to an equipotent, non-CNS penetrant thieno[2,3-c]pyrdin-7(6H)-one core. Medicinal chemistry design efforts yielded two novel tricyclic cores that enhanced M4 PAM potency, regained CNS penetration, displayed favorable DMPK properties and afforded robust in vivo efficacy in reversing amphetamine-induced hyperlocomotion in rats.
Asunto(s)
Aldehído Oxidasa/metabolismo , Miotonía Congénita/metabolismo , Receptor Muscarínico M4/metabolismo , Animales , Descubrimiento de Drogas , Humanos , Ratas , Relación Estructura-ActividadRESUMEN
Rett syndrome (RS) is a neurodevelopmental disorder that shares many symptomatic and pathological commonalities with idiopathic autism. Alterations in protein synthesis-dependent synaptic plasticity (PSDSP) are a hallmark of a number of syndromic forms of autism; in the present work, we explore the consequences of disruption and rescue of PSDSP in a mouse model of RS. We report that expression of a key regulator of synaptic protein synthesis, the metabotropic glutamate receptor 5 (mGlu5) protein, is significantly reduced in both the brains of RS model mice and in the motor cortex of human RS autopsy samples. Furthermore, we demonstrate that reduced mGlu5 expression correlates with attenuated DHPG-induced long-term depression in the hippocampus of RS model mice, and that administration of a novel mGlu5 positive allosteric modulator (PAM), termed VU0462807, can rescue synaptic plasticity defects. Additionally, treatment of Mecp2-deficient mice with VU0462807 improves motor performance (open-field behavior and gait dynamics), corrects repetitive clasping behavior, as well as normalizes cued fear-conditioning defects. Importantly, due to the rationale drug discovery approach used in its development, our novel mGlu5 PAM improves RS phenotypes and synaptic plasticity defects without evoking the overt adverse effects commonly associated with potentiation of mGlu5 signaling (i.e. seizures), or affecting cardiorespiratory defects in RS model mice. These findings provide strong support for the continued development of mGlu5 PAMs as potential therapeutic agents for use in RS, and, more broadly, for utility in idiopathic autism.
Asunto(s)
Trastorno Autístico/genética , Receptor del Glutamato Metabotropico 5/genética , Síndrome de Rett/genética , Convulsiones/genética , Adulto , Regulación Alostérica/genética , Animales , Trastorno Autístico/tratamiento farmacológico , Trastorno Autístico/patología , Autopsia , Modelos Animales de Enfermedad , Femenino , Regulación de la Expresión Génica/efectos de los fármacos , Hipocampo/efectos de los fármacos , Hipocampo/patología , Humanos , Masculino , Proteína 2 de Unión a Metil-CpG/genética , Ratones , Ratones Noqueados , Corteza Motora/efectos de los fármacos , Corteza Motora/patología , Plasticidad Neuronal/efectos de los fármacos , Pirazoles/administración & dosificación , Pirimidinonas/administración & dosificación , Receptor del Glutamato Metabotropico 5/biosíntesis , Síndrome de Rett/tratamiento farmacológico , Síndrome de Rett/patología , Convulsiones/tratamiento farmacológico , Convulsiones/patología , Transducción de Señal/efectos de los fármacos , Adulto JovenRESUMEN
Mutations in the MeCP2 gene are responsible for the neurodevelopmental disorder Rett syndrome (RTT). MeCP2 is a DNA-binding protein whose abundance and ability to complex with histone deacetylase 3 is linked to the regulation of chromatin structure. Consequently, loss-of-function mutations in MeCP2 are predicted to have broad effects on gene expression. However, to date, studies in mouse models of RTT have identified a limited number of gene or pathway-level disruptions, and even fewer genes have been identified that could be considered amenable to classic drug discovery approaches. Here, we performed RNA sequencing (RNA-seq) on nine motor cortex and six cerebellar autopsy samples from RTT patients and controls. This approach identified 1887 significantly affected genes in the motor cortex and 2110 genes in the cerebellum, with a global trend toward increased expression. Pathway-level analysis identified enrichment in genes associated with mitogen-activated protein kinase signaling, long-term potentiation, and axon guidance. A survey of our RNA-seq results also identified a significant decrease in expression of the CHRM4 gene, which encodes a receptor [muscarinic acetylcholine receptor 4 (M4)] that is the subject of multiple large drug discovery efforts for schizophrenia and Alzheimer's disease. We confirmed that CHRM4 expression was decreased in RTT patients, and, excitingly, we demonstrated that M4 potentiation normalizes social and cognitive phenotypes in Mecp2+/- mice. This work provides an experimental paradigm in which translationally relevant targets can be identified using transcriptomics in RTT autopsy samples, back-modeled in Mecp2+/- mice, and assessed for preclinical efficacy using existing pharmacological tool compounds.
Asunto(s)
Terapia Molecular Dirigida , Receptor Muscarínico M4/metabolismo , Síndrome de Rett/tratamiento farmacológico , Síndrome de Rett/genética , Análisis de Secuencia de ARN , Animales , Autopsia , Cerebelo/metabolismo , Humanos , Ratones , Corteza Motora/metabolismo , Receptor Muscarínico M4/genética , Síndrome de Rett/metabolismo , Síndrome de Rett/patologíaRESUMEN
Cocaine use disorder (CUD) remains a debilitating health problem in the United States for which there are no Food and Drug Administration-approved treatment options. Accumulating anatomical and electrophysiological evidence indicates that the muscarinic acetylcholine receptor (mAChR) subtype 5 (M5 ) plays a critical role in the regulation of the mesolimbic dopaminergic reward circuitry, a major site of action for cocaine and other psychostimulants. In addition, M5 knockout mice exhibit reduced cocaine self-administration behaviors with no differences in sugar pellet-maintained responding relative to wild-type mice. These findings suggest that selective inhibition of M5 mAChR may provide a novel pharmacological approach for targeting CUD. Recently, we reported the synthesis and characterization of ML375, a selective negative allosteric modulator (NAM) for the rat and human M5 mAChR with optimized pharmacokinetic properties for systemic dosing in rodents. In the present study, male Sprague-Dawley rats were trained to self-administer intravenous cocaine (0.1-0.75 mg/kg/infusion) under a 10-response fixed ratio or a progressive ratio schedule of reinforcement. Under both schedules of reinforcement, ML375 produced dose-related reductions in cocaine self-administration. ML375 also modestly reduced sugar pellet-maintained responding on the 10-response, fixed ratio schedule but had no effect under a progressive ratio schedule of reinforcement. Further, ML375 did not affect general motor output as assessed by a rotarod test. Collectively, these results provide the first demonstration that selective inhibition of M5 using the M5 NAM ML375 can attenuate both the reinforcing effects and the relative strength of cocaine and suggest that M5 NAMs may represent a promising, novel treatment approach for CUD.
Asunto(s)
Trastornos Relacionados con Cocaína/prevención & control , Cocaína/administración & dosificación , Receptor Muscarínico M5/antagonistas & inhibidores , Animales , Conducta Animal/efectos de los fármacos , Condicionamiento Operante , Modelos Animales de Enfermedad , Inhibidores de Captación de Dopamina/administración & dosificación , Relación Dosis-Respuesta a Droga , Masculino , Ratones , Ratas , Ratas Sprague-Dawley , Esquema de Refuerzo , Recompensa , AutoadministraciónRESUMEN
Mutations that lead to Huntington's disease (HD) result in increased transmission at glutamatergic corticostriatal synapses at early presymptomatic stages that have been postulated to set the stage for pathological changes and symptoms that are observed at later ages. Based on this, pharmacological interventions that reverse excessive corticostriatal transmission may provide a novel approach for reducing early physiological changes and motor symptoms observed in HD. We report that activation of the M4 subtype of muscarinic acetylcholine receptor reduces transmission at corticostriatal synapses and that this effect is dramatically enhanced in presymptomatic YAC128 HD and BACHD relative to wild-type mice. Furthermore, chronic administration of a novel highly selective M4 positive allosteric modulator (PAM) beginning at presymptomatic ages improves motor and synaptic deficits in 5-mo-old YAC128 mice. These data raise the exciting possibility that selective M4 PAMs could provide a therapeutic strategy for the treatment of HD.
Asunto(s)
Regulación Alostérica/fisiología , Ácido Glutámico/metabolismo , Enfermedad de Huntington/tratamiento farmacológico , Receptor Muscarínico M4/fisiología , Transmisión Sináptica/fisiología , Animales , Encéfalo/metabolismo , Fluorescencia , Enfermedad de Huntington/fisiopatología , Inmunohistoquímica , Ratones , Ratones Mutantes , Piridazinas/farmacología , Piridazinas/uso terapéutico , Prueba de Desempeño de Rotación con Aceleración Constante , Transmisión Sináptica/efectos de los fármacos , Tiofenos/farmacología , Tiofenos/uso terapéuticoRESUMEN
This letter describes the continued optimization of M5 NAM ML375 (VU0483253). While a valuable in vivo tool compound, ML375has an excessively long elimination half-life in rat (t1/2=80h), which can be problematic in certain rodent addiction paradigms (e.g., reinstatement). Thus, we required an M5 NAM of comparable potency to ML375, but with a rat t1/2 of less than 4h. Steep SAR plagued this chemotype, and here we detail aniline replacements that offered some improvements over ML375, but failed to advance. Ultimately, incorporation of a single methyl group to the 9b-phenyl ring acted as a metabolic shunt, providing (S)-11 (VU6008667), an equipotent M5 NAM, with high CNS penetration, excellent selectivity versus M1-4 and the desired short half-life (t1/2=2.3h) in rat.
Asunto(s)
Sistema Nervioso Central/metabolismo , Antagonistas Muscarínicos/farmacología , Receptor Muscarínico M5/efectos de los fármacos , Animales , Semivida , Antagonistas Muscarínicos/farmacocinética , RatasRESUMEN
Based on a hypothesis that an intramolecular hydrogen bond was present in our lead series of picolinamide mGlu5 NAMs, we reasoned that an inactive nicotinamide series could be modified through introduction of a fused heterocyclic core to generate potent mGlu5 NAMs. In this Letter, we describe the synthesis and evaluation of compounds that demonstrate the viability of that approach. Selected analogs were profiled in a variety of in vitro assays, and two compounds were evaluated in rat pharmacokinetic studies and a mouse model of obsessive-compulsive disorder. Ancillary pharmacology screening revealed that members of this series exhibited moderate inhibition of the dopamine transporter (DAT), and SAR was developed that expanded the selectivity for mGlu5 versus DAT.
Asunto(s)
Amidas/química , Receptor del Glutamato Metabotropico 5/metabolismo , Regulación Alostérica , Amidas/farmacocinética , Amidas/farmacología , Animales , Permeabilidad de la Membrana Celular/efectos de los fármacos , Perros , Proteínas de Transporte de Dopamina a través de la Membrana Plasmática/antagonistas & inhibidores , Proteínas de Transporte de Dopamina a través de la Membrana Plasmática/metabolismo , Evaluación Preclínica de Medicamentos , Semivida , Humanos , Concentración 50 Inhibidora , Células de Riñón Canino Madin Darby , Ratones , Microsomas Hepáticos/metabolismo , Piridinas/química , Ratas , Receptor del Glutamato Metabotropico 5/química , Relación Estructura-Actividad , Triazoles/químicaRESUMEN
This letter describes the chemical optimization of a novel series of M4 positive allosteric modulators (PAMs) based on a 5-amino-thieno[2,3-c]pyridazine core, developed via iterative parallel synthesis, and culminating in the highly utilized rodent in vivo tool compound, VU0467154 (5). This is the first report of the optimization campaign (SAR and DMPK profiling) that led to the discovery of VU0467154, and details all of the challenges faced in allosteric modulator programs (steep SAR, species differences in PAM pharmacology and subtle structural changes affecting CNS penetration).
Asunto(s)
Piridazinas/farmacología , Receptor Muscarínico M4/agonistas , Tiofenos/farmacología , Animales , Humanos , Ligandos , Proteínas de Transporte de Nucleósidos/metabolismo , Piridazinas/administración & dosificación , Piridazinas/síntesis química , Piridazinas/farmacocinética , Ratas Sprague-Dawley , Relación Estructura-Actividad , Tiofenos/administración & dosificación , Tiofenos/síntesis química , Tiofenos/farmacocinéticaRESUMEN
This letter details the continued chemical optimization of a novel series of M4 positive allosteric modulators (PAMs) based on a 5-amino-thieno[2,3-c]pyridazine core by incorporating a 3-amino azetidine amide moiety. The analogs described within this work represent the most potent M4 PAMs reported for this series to date. The SAR to address potency, clearance, subtype selectivity, CNS exposure, and P-gp efflux are described. This work culminated in the discovery of VU6000918, which demonstrated robust efficacy in a rat amphetamine-induced hyperlocomotion reversal model at a minimum efficacious dose of 0.3mg/kg.
Asunto(s)
Amidas/farmacología , Azetidinas/farmacología , Receptor Muscarínico M4/antagonistas & inhibidores , Regulación Alostérica/efectos de los fármacos , Amidas/síntesis química , Amidas/química , Animales , Azetidinas/síntesis química , Azetidinas/química , Modelos Animales de Enfermedad , Relación Dosis-Respuesta a Droga , Humanos , Estructura Molecular , Ratas , Relación Estructura-ActividadRESUMEN
Herein we describe the continued optimization of M4 positive allosteric modulators (PAMs) within the 5-amino-thieno[2,3-c]pyridazine series of compounds. In this letter, we disclose our studies on tertiary amides derived from substituted azetidines. This series provided excellent CNS penetration, which had been challenging to consistently achieve in other amide series. Efforts to mitigate high clearance, aided by metabolic softspot analysis, were unsuccessful and precluded this series from further consideration as a preclinical candidate. In the course of this study, we found that potassium tetrafluoroborate salts could be engaged in a tosyl hydrazone reductive cross coupling reaction, a previously unreported transformation, which expands the synthetic utility of the methodology.
Asunto(s)
Amidas/química , Azetidinas/química , Receptor Muscarínico M4/metabolismo , Regulación Alostérica , Amidas/metabolismo , Evaluación Preclínica de Medicamentos , Humanos , Unión Proteica , Piridazinas/síntesis química , Piridazinas/química , Piridazinas/metabolismo , Receptor Muscarínico M4/antagonistas & inhibidores , Relación Estructura-ActividadRESUMEN
This letter describes the further chemical optimization of the 5-amino-thieno[2,3-c]pyridazine series (VU0467154/VU0467485) of M4 positive allosteric modulators (PAMs), developed via iterative parallel synthesis, culminating in the discovery of the non-human primate (NHP) in vivo tool compound, VU0476406 (8p). VU0476406 is an important in vivo tool compound to enable translation of pharmacodynamics from rodent to NHP, and while data related to a Parkinson's disease model has been reported with 8p, this is the first disclosure of the optimization and discovery of VU0476406, as well as detailed pharmacology and DMPK properties.