RESUMEN
This Letter details our efforts to discover structurally unique M4 PAMs containing 5,6-heteroaryl ring systems. In an attempt to improve the DMPK profiles of the 2,3-dimethyl-2H-indazole-5-carboxamide and 1-methyl-1H-benzo[d][1,2,3]triazole-6-carboxamide cores, we investigated a plethora of core replacements. This exercise identified a novel 2,3-dimethylimidazo[1,2-a]pyrazine-6-carboxamide core that provided improved M4 PAM activity and CNS penetration.
Asunto(s)
Imidazoles/química , Pirazinas/química , Receptor Muscarínico M4/química , Regulación Alostérica , Diseño de Fármacos , Evaluación Preclínica de Medicamentos , Humanos , Imidazoles/metabolismo , Cinética , Unión Proteica , Pirazinas/metabolismo , Receptor Muscarínico M4/metabolismo , 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 details our efforts to replace the 3-amino moiety, an essential pharmacophore for M4 PAM activity in most M4 PAMs to date, within the thieno[2,3-b]pyridine core, as the ß-amino carboxamide motif has been shown to engender poor solubility, varying degrees of P-gp efflux and represents a structural alert. A scaffold hopping exercise identified a novel 2,4-dimethylquinoline carboxamide core that provided M4 PAM activity and good CNS penetration without an amino moiety. In addition, MacMillan photoredox catalysis chemistry was essential for construction of the 2,4-dimethylquinoline core.
Asunto(s)
Amidas/química , Receptor Muscarínico M4/metabolismo , Regulación Alostérica , Amidas/síntesis química , Amidas/farmacocinética , Animales , Encéfalo/metabolismo , Evaluación Preclínica de Medicamentos , Semivida , Unión Proteica , Piridinas/química , Ratas , Ratas Sprague-Dawley , Receptor Muscarínico M4/química , Relación Estructura-ActividadRESUMEN
Once thought to be an artifact of microsomal systems, atypical kinetics with cytochrome P450 (CYP) enzymes have been extensively investigated in vitro and found to be substrate and species dependent. Building upon increasing reports of heterotropic CYP activation and inhibition in clinical settings, we screened a compound library of clinically approved drugs and various probe compounds to identify the frequency of heterotropism observed with different drug classes and the associated CYP enzymes thereof (1A2, 2C9, 2D6, and 3A4/5). Results of this screen revealed that the prescribed androgen receptor antagonist flutamide activated the intrinsic midazolam hydroxylase activity of CYP3A in human hepatic microsomes (66%), rat and human hepatocytes (36 and 160%, respectively), and in vivo in male Sprague-Dawley rats (>2-fold, combined area under the curve of primary rat in vivo midazolam metabolites). In addition, a screen of the pharmacologically active metabolite 2-hydroxy-flutamide revealed that this principle metabolite increased CYP3A metabolism of midazolam in human microsomes (30%) and hepatocytes (110%). Importantly, both flutamide and 2-hydroxy-flutamide demonstrated a pronounced increase in the CYP3A-mediated metabolism of commonly paired medications, nifedipine (antihypertensive) and amiodarone (antiarrhythmic), in multispecies hepatocytes (100% over baseline). These data serve to highlight the importance of an appropriate substrate and in vitro system selection in the pharmacokinetic modeling of atypical enzyme kinetics. In addition, the results of our investigation have illuminated a previously undiscovered class of heterotropic CYP3A activators and have demonstrated the importance of selecting commonly paired therapeutics in the in vitro and in vivo modeling of projected clinical outcomes.
Asunto(s)
Antagonistas de Receptores Androgénicos/metabolismo , Citocromo P-450 CYP3A/metabolismo , Activadores de Enzimas/metabolismo , Flutamida/metabolismo , Antagonistas de Receptores Androgénicos/farmacología , Animales , Evaluación Preclínica de Medicamentos/métodos , Activadores de Enzimas/farmacología , Femenino , Flutamida/farmacología , Cobayas , Humanos , Masculino , Ratones , Microsomas Hepáticos/efectos de los fármacos , Microsomas Hepáticos/enzimología , Ratas , Ratas Sprague-Dawley , Porcinos , Porcinos EnanosRESUMEN
We report the discovery and SAR of two novel series of imidazopyrimidinones and dihydroimidazopyrimidinones as metabotropic glutamate receptor 5 (mGlu5) positive allosteric modulators (PAMs). Exploration of several structural features in the western and eastern part of the imidazopyrimidinone core and combinations thereof, revealed compound 4a as a mGlu5 PAM with good in vitro potency and efficacy, acceptable drug metabolism and pharmacokinetic (DMPK) properties and in vivo efficacy in an amphetamine-based model of psychosis. However, the presence of CNS-mediated adverse effects in preclinical species precluded any further in vivo evaluation.
Asunto(s)
Antipsicóticos/química , Compuestos Heterocíclicos con 2 Anillos/química , Imidazoles/química , Pirimidinonas/química , Receptor del Glutamato Metabotropico 5/química , Regulación Alostérica , Animales , Antipsicóticos/síntesis química , Antipsicóticos/farmacocinética , Encéfalo/metabolismo , Evaluación Preclínica de Medicamentos , Semivida , Compuestos Heterocíclicos con 2 Anillos/síntesis química , Compuestos Heterocíclicos con 2 Anillos/farmacocinética , Humanos , Imidazoles/síntesis química , Imidazoles/farmacocinética , Locomoción/efectos de los fármacos , Microsomas Hepáticos/metabolismo , Unión Proteica , Pirimidinonas/síntesis química , Pirimidinonas/farmacocinética , Ratas , Receptor del Glutamato Metabotropico 5/metabolismo , Relación Estructura-ActividadRESUMEN
A functional high throughput screen identified a novel chemotype for the positive allosteric modulation (PAM) of the muscarinic acetylcholine receptor (mAChR) subtype 5 (M5). Application of rapid analog, iterative parallel synthesis efficiently optimized M5 potency to arrive at the most potent M5 PAMs prepared to date and provided tool compound 8n (ML380) demonstrating modest CNS penetration (human M5 EC50 = 190 nM, rat M5 EC50 = 610 nM, brain to plasma ratio (Kp) of 0.36).
Asunto(s)
Sistema Nervioso Central/metabolismo , Descubrimiento de Drogas , Indazoles/metabolismo , Indazoles/farmacología , Piperidinas/metabolismo , Piperidinas/farmacología , Receptor Muscarínico M5/química , Receptor Muscarínico M5/metabolismo , Sulfonamidas/metabolismo , Sulfonamidas/farmacología , Regulación Alostérica/efectos de los fármacos , Animales , Evaluación Preclínica de Medicamentos , Ensayos Analíticos de Alto Rendimiento , Humanos , Indazoles/química , Indazoles/farmacocinética , Masculino , Piperidinas/química , Piperidinas/farmacocinética , Ratas , Especificidad por Sustrato , Sulfonamidas/química , Sulfonamidas/farmacocinéticaRESUMEN
Of the five G-protein-coupled muscarinic acetylcholine receptors (mAChRs; M1-M5), M5 is the least explored and understood due to a lack of mAChR subtype-selective ligands. We recently performed a high-throughput functional screen and identified a number of weak antagonist hits that are selective for the M5 receptor. Here, we report an iterative parallel synthesis and detailed molecular pharmacologic profiling effort that led to the discovery of the first highly selective, central nervous system (CNS)-penetrant M5-orthosteric antagonist, with sub-micromolar potency (hM5 IC50=450â nM, hM5 Ki=340â nM, M1-M4 IC50>30â µM), enantiospecific inhibition, and an acceptable drug metabolism and pharmacokinetics (DMPK) profile for in vitro and electrophysiology studies. This compound will be a powerful tool and molecular probe for the further investigation into the role of M5 in addiction and other diseases.
Asunto(s)
Acetofenonas/química , Isoxazoles/química , Sondas Moleculares/química , Antagonistas Muscarínicos/química , Receptor Muscarínico M5/antagonistas & inhibidores , Acetofenonas/metabolismo , Acetofenonas/farmacocinética , Animales , Evaluación Preclínica de Medicamentos , Semivida , Humanos , Isoxazoles/metabolismo , Isoxazoles/farmacocinética , Sondas Moleculares/metabolismo , Sondas Moleculares/farmacocinética , Antagonistas Muscarínicos/metabolismo , Antagonistas Muscarínicos/farmacocinética , Unión Proteica , Ratas , Receptor Muscarínico M5/metabolismoRESUMEN
A functional high throughput screen and subsequent multidimensional, iterative parallel synthesis effort identified the first muscarinic acetylcholine receptor (mAChR) negative allosteric modulator (NAM) selective for the M5 subtype. ML375 is a highly selective M5 NAM with submicromolar potency (human M5 IC50 = 300 nM, rat M5 IC50 = 790 nM, M1-M4 IC50 > 30 µM), excellent multispecies PK, high CNS penetration, and enantiospecific inhibition.
Asunto(s)
Encéfalo/metabolismo , Descubrimiento de Drogas , Imidazoles/química , Imidazoles/farmacología , Indoles/química , Indoles/farmacología , Receptor Muscarínico M5/metabolismo , Regulación Alostérica/efectos de los fármacos , Animales , Encéfalo/efectos de los fármacos , Células CHO , Cricetinae , Cricetulus , Evaluación Preclínica de Medicamentos , Humanos , Imidazoles/metabolismo , Imidazoles/farmacocinética , Indoles/metabolismo , Indoles/farmacocinética , Masculino , Ratas , Receptor Muscarínico M5/química , Relación Estructura-Actividad , Especificidad por SustratoRESUMEN
Herein we report a next generation muscarinic receptor 4 (M(4)) positive allosteric modulator (PAM), ML253 which exhibits nanomolar activity at both the human (EC(50)=56 nM) and rat (EC(50)=176 nM) receptors and excellent efficacy by the left-ward shift of the ACh concentration response curve (fold shift, human=106; rat=50). In addition, ML253 is selective against the four other muscarinic subtypes, displays excellent CNS exposure and is active in an amphetamine-induced hyperlocomotion assay.
Asunto(s)
Amidas/química , Encéfalo/metabolismo , Piridinas/química , Receptor Muscarínico M4/metabolismo , Tiofenos/química , Regulación Alostérica , Amidas/farmacocinética , Amidas/uso terapéutico , Animales , Encéfalo/efectos de los fármacos , Colinérgicos/química , Colinérgicos/farmacocinética , Colinérgicos/uso terapéutico , Modelos Animales de Enfermedad , Evaluación Preclínica de Medicamentos , Semivida , Humanos , Unión Proteica , Piridinas/farmacocinética , Piridinas/uso terapéutico , Ratas , Receptor Muscarínico M4/química , Esquizofrenia/tratamiento farmacológico , Relación Estructura-Actividad , Tiofenos/farmacocinética , Tiofenos/uso terapéuticoRESUMEN
Herein we describe the discovery and development of a novel class of M(4) positive allosteric modulators, culminating in the discovery of ML293. ML293 exhibited modest potency at the human M4 receptor (EC(50)=1.3 µM) and excellent efficacy as noted by the 14.6-fold leftward shift of the agonist concentration-response curve. ML293 was also selective versus the other muscarinic subtypes and displayed excellent in vivo PK properties in rat with low IV clearance (11.6 mL/min/kg) and excellent brain exposure (PO PBL, 10 mg/kg at 1h, [Brain]=10.3 µM, B:P=0.85).