RESUMEN
A novel series of 3-amino-piperidin-2-one-based calcitonin gene-related peptide (CGRP) receptor antagonists was invented based upon the discovery of unexpected structure-activity observations. Initial exploration of the structure-activity relationships enabled the generation of a moderately potent lead structure (4). A series of modifications, including ring contraction and inversion of stereocenters, led to surprising improvements in CGRP receptor affinity. These studies identified compound 23, a structurally novel potent, orally bioavailable CGRP receptor antagonist.
RESUMEN
Current therapies for chronic pain can have insufficient efficacy and lead to side effects, necessitating research of novel targets against pain. Although originally identified as an oncogene, Tropomyosin-related kinase A (TrkA) is linked to pain and elevated levels of NGF (the ligand for TrkA) are associated with chronic pain. Antibodies that block TrkA interaction with its ligand, NGF, are in clinical trials for pain relief. Here, we describe the identification of TrkA-specific inhibitors and the structural basis for their selectivity over other Trk family kinases. The X-ray structures reveal a binding site outside the kinase active site that uses residues from the kinase domain and the juxtamembrane region. Three modes of binding with the juxtamembrane region are characterized through a series of ligand-bound complexes. The structures indicate a critical pharmacophore on the compounds that leads to the distinct binding modes. The mode of interaction can allow TrkA selectivity over TrkB and TrkC or promiscuous, pan-Trk inhibition. This finding highlights the difficulty in characterizing the structure-activity relationship of a chemical series in the absence of structural information because of substantial differences in the interacting residues. These structures illustrate the flexibility of binding to sequences outside of-but adjacent to-the kinase domain of TrkA. This knowledge allows development of compounds with specificity for TrkA or the family of Trk proteins.
Asunto(s)
Inhibidores de Proteínas Quinasas/química , Inhibidores de Proteínas Quinasas/farmacología , Receptor trkA/antagonistas & inhibidores , Receptor trkA/química , Secuencia de Aminoácidos , Sitios de Unión , Cristalografía por Rayos X , Evaluación Preclínica de Medicamentos , Humanos , Cinética , Glicoproteínas de Membrana/antagonistas & inhibidores , Glicoproteínas de Membrana/química , Glicoproteínas de Membrana/genética , Modelos Moleculares , Conformación Proteica , Inhibidores de Proteínas Quinasas/síntesis química , Receptor trkA/genética , Receptor trkB/antagonistas & inhibidores , Receptor trkB/química , Receptor trkB/genética , Receptor trkC/antagonistas & inhibidores , Receptor trkC/química , Receptor trkC/genética , Proteínas Recombinantes/química , Proteínas Recombinantes/efectos de los fármacos , Proteínas Recombinantes/genética , Relación Estructura-Actividad , Resonancia por Plasmón de SuperficieRESUMEN
While a correlation between blockade of the orexin 2 receptor (OX2R) with either a dual orexin receptor antagonist (DORA) or a selective orexin 2 receptor antagonist (2-SORA) and a decrease of wakefulness is well established, less is known about selective blockade of the orexin 1 receptor (OX1R). Therefore, a highly selective orexin 1 antagonist (1-SORA) with suitable properties to allow in vivo interrogation of OX1R specific pharmacology in preclinical species remains an attractive target. Herein, we describe the discovery of an optimized 1-SORA series in the piperidine ether class. Notably, a 4,4-difluoropiperidine core coupled with a 2-quinoline ether linkage provides OX1R selective compounds. The combination with an azabenzimidazole or imidazopyridine amide substituent leads to analogs 47 and 51 with >625-fold functional selectivity for OX1R over OX2R in rat. Compounds 47 and 51 possess clean off-target profiles and the required pharmacokinetic and physical properties to be useful as 1-SORA tool compounds.
Asunto(s)
Antagonistas de los Receptores de Orexina/química , Antagonistas de los Receptores de Orexina/farmacología , Receptores de Orexina/metabolismo , Piperidinas/química , Piperidinas/farmacología , Animales , Descubrimiento de Drogas , Humanos , Piperidinas/farmacocinética , Ratas , Ratas Transgénicas , Relación Estructura-ActividadRESUMEN
In our efforts to develop CGRP receptor antagonists as backups to MK-3207, 2, we employed a scaffold hopping approach to identify a series of novel oxazolidinone-based compounds. The development of a structurally diverse, potent (20, cAMP+HS IC50=0.67 nM), and selective compound (hERG IC50=19 µM) with favorable rodent pharmacokinetics (F=100%, t1/2=7h) is described. Key to this development was identification of a 3-substituted spirotetrahydropyran ring that afforded a substantial gain in potency (10 to 35-fold).
Asunto(s)
Antagonistas del Receptor Peptídico Relacionado con el Gen de la Calcitonina , Trastornos Migrañosos/tratamiento farmacológico , Oxazolidinonas/farmacología , Oxazolidinonas/uso terapéutico , Animales , Relación Dosis-Respuesta a Droga , Humanos , Simulación del Acoplamiento Molecular , Estructura Molecular , Oxazolidinonas/síntesis química , Oxazolidinonas/química , Ratas , Relación Estructura-ActividadRESUMEN
A new class of CGRP receptor antagonists was identified by replacing the central amide of a previously identified anilide lead structure with ethylene, ethane, or ethyne linkers. (E)-Alkenes as well as alkynes were found to preserve the proper bioactive conformation of the amides, necessary for efficient receptor binding. Further exploration resulted in several potent compounds against CGRP-R with low susceptibility to P-gp mediated efflux.
Asunto(s)
Alquenos/farmacología , Antagonistas del Receptor Peptídico Relacionado con el Gen de la Calcitonina , Alquenos/síntesis química , Alquenos/química , Amidas/química , Relación Dosis-Respuesta a Droga , Células HEK293 , Humanos , Estructura Molecular , Relación Estructura-ActividadRESUMEN
Rational modification of the clinically tested CGRP receptor antagonist MK-3207 (3) afforded an analogue with increased unbound fraction in rat plasma and enhanced aqueous solubility, 2-[(8R)-8-(3,5-difluorophenyl)-8-methyl-10-oxo-6,9-diazaspiro[4.5]dec-9-yl]-N-[(6S)-2'-oxo-1',2',5,7-tetrahydrospiro[cyclopenta[b]pyridine-6,3'-pyrrolo[2,3-b]pyridin]-3-yl]acetamide (MK-8825) (6). Compound 6 maintained similar affinity to 3 at the human and rat CGRP receptors but possessed significantly improved in vivo potency in a rat pharmacodynamic model. The overall profile of 6 indicates it should find utility as a rat tool to investigate effects of CGRP receptor blockade in vivo.
Asunto(s)
Analgésicos/síntesis química , Analgésicos/farmacología , Antagonistas del Receptor Peptídico Relacionado con el Gen de la Calcitonina , Trastornos Migrañosos/tratamiento farmacológico , Piridinas/síntesis química , Piridinas/farmacología , Compuestos de Espiro/síntesis química , Compuestos de Espiro/farmacología , Administración Oral , Analgésicos/sangre , Animales , Disponibilidad Biológica , Modelos Animales de Enfermedad , Perros , Humanos , Macaca mulatta , Ratones , Piridinas/sangre , Ratas , Receptores de Péptido Relacionado con el Gen de Calcitonina/metabolismo , Especificidad de la Especie , Compuestos de Espiro/sangreRESUMEN
A novel series of potent CGRP receptor antagonists containing a central quinoline ring constraint was identified. The combination of the quinoline constraint with a tricyclic benzimidazolinone left hand fragment produced an analog with picomolar potency (14, CGRP K(i)=23 pM). Further optimization of the tricycle produced a CGRP receptor antagonist that exhibited subnanomolar potency (19, CGRP K(i)=0.52 nM) and displayed a good pharmacokinetic profile in three preclinical species.
Asunto(s)
Antagonistas del Receptor Peptídico Relacionado con el Gen de la Calcitonina , Quinolinas/farmacología , Animales , Disponibilidad Biológica , Perros , Evaluación Preclínica de Medicamentos , Macaca mulatta , Quinolinas/química , Quinolinas/farmacocinética , RatasRESUMEN
A novel class of CGRP receptor antagonists was rationally designed by modifying a highly potent, but structurally complex, CGRP receptor antagonist. Initial modifications focused on simplified structures, with increased flexibility. Subsequent to the preparation of a less-potent but more flexible lead, classic medicinal chemistry methods were applied to restore high affinity (compound 22, CGRP Ki=0.035 nM) while maintaining structural diversity relative to the lead. Good selectivity against the closely related adrenomedullin-2 receptor was also achieved.
Asunto(s)
Acetamidas/química , Antagonistas del Receptor Peptídico Relacionado con el Gen de la Calcitonina , Compuestos de Espiro/química , Acetamidas/síntesis química , Acetamidas/farmacología , Animales , Línea Celular , Diseño de Fármacos , Humanos , Ratas , Receptores de Péptido Relacionado con el Gen de Calcitonina/metabolismo , Compuestos de Espiro/síntesis química , Compuestos de Espiro/farmacología , Relación Estructura-ActividadRESUMEN
Rational modification of a previously identified spirohydantoin lead structure has identified a series of potent spiroazaoxindole CGRP receptor antagonists. The azaoxindole was found to be a general replacement for the hydantoin that consistently improved in vitro potency. The combination of the indanylspiroazaoxindole and optimized benzimidazolinones led to highly potent antagonists (e.g., 25, CGRP K(i)=40pM). The closely related compound 27 demonstrated good oral bioavailability in dog and rhesus.
Asunto(s)
Antagonistas del Receptor Peptídico Relacionado con el Gen de la Calcitonina , Indoles/síntesis química , Compuestos de Espiro/síntesis química , Administración Oral , Animales , Disponibilidad Biológica , Perros , Descubrimiento de Drogas , Humanos , Indoles/farmacología , Macaca mulatta , Oxindoles , Compuestos de Espiro/farmacología , Relación Estructura-ActividadRESUMEN
Previous work has suggested that activation of mGlu5 receptor augments NMDA receptor function and thereby may constitute a rational approach addressing glutamate hypofunction in schizophrenia and a target for novel antipsychotic drug development. Here, we report the in vitro activity, in vivo efficacy and safety profile of 5PAM523 (4-Fluorophenyl){(2R,5S)-5-[5-(5-fluoropyridin-2-yl)-1,2,4-oxadiazol-3-yl]-2-methylpiperidin-1-yl}methanone), a structurally novel positive allosteric modulator selective of mGlu5. In cells expressing human mGlu5 receptor, 5PAM523 potentiated threshold responses to glutamate in fluorometric calcium assays, but does not have any intrinsic agonist activity. 5PAM523 acts as an allosteric modulator as suggested by the binding studies showing that 5PAM523 did not displace the binding of the orthosteric ligand quisqualic acid, but did partially compete with the negative allosteric modulator, MPyEP. In vivo, 5PAM523 reversed amphetamine-induced locomotor activity in rats. Therefore, both the in vitro and in vivo data demonstrate that 5PAM523 acts as a selective mGlu5 PAM and exhibits anti-psychotic like activity. To study the potential for adverse effects and particularly neurotoxicity, brain histopathological exams were performed in rats treated for 4 days with 5PAM523 or vehicle. The brain exam revealed moderate to severe neuronal necrosis in the rats treated with the doses of 30 and 50 mg/kg, particularly in the auditory cortex and hippocampus. To investigate whether this neurotoxicity is mechanism specific to 5PAM523, similar safety studies were carried out with three other structurally distinct selective mGlu5 PAMs. Results revealed a comparable pattern of neuronal cell death. Finally, 5PAM523 was tested in mGlu5 knock-out (KO) and wild type (WT) mice. mGlu5 WT mice treated with 5PAM523 for 4 days at 100 mg/kg presented significant neuronal death in the auditory cortex and hippocampus. Conversely, mGlu5 KO mice did not show any neuronal loss by histopathology, suggesting that enhancement of mGlu5 function is responsible for the toxicity of 5PAM523. This study reveals for the first time that augmentation of mGlu5 function with selective allosteric modulators results in neurotoxicity.
Asunto(s)
Antipsicóticos/toxicidad , Benzamidas/toxicidad , Encéfalo/efectos de los fármacos , Muerte Celular/efectos de los fármacos , Fármacos actuantes sobre Aminoácidos Excitadores/toxicidad , Oxadiazoles/toxicidad , Receptor del Glutamato Metabotropico 5/metabolismo , Regulación Alostérica , Animales , Antipsicóticos/química , Antipsicóticos/farmacocinética , Benzamidas/química , Benzamidas/farmacocinética , Encéfalo/patología , Encéfalo/fisiopatología , Células CHO , Muerte Celular/fisiología , Células Cultivadas , Cricetulus , Fármacos actuantes sobre Aminoácidos Excitadores/química , Fármacos actuantes sobre Aminoácidos Excitadores/farmacocinética , Femenino , Humanos , Masculino , Ratones de la Cepa 129 , Ratones Noqueados , Necrosis/patología , Necrosis/fisiopatología , Neuronas/efectos de los fármacos , Neuronas/patología , Neuronas/fisiología , Síndromes de Neurotoxicidad/patología , Síndromes de Neurotoxicidad/fisiopatología , Oxadiazoles/química , Oxadiazoles/farmacocinética , Ratas Sprague-Dawley , Ratas Wistar , Receptor del Glutamato Metabotropico 5/genéticaRESUMEN
Rational modification of the potent calcitonin gene-related peptide (CGRP) receptor antagonist MK-3207 led to a series of analogues with enhanced CNS penetrance and a convenient chemical handle for introduction of a radiolabel. A number of (11)C-tracers were synthesized and evaluated in vivo, leading to the identification of [(11)C]8 ([(11)C]MK-4232), the first positron emission tomography tracer for the CGRP receptor.
RESUMEN
Incorporation of polar functionality into a series of highly potent calcitonin gene-related peptide (CGRP) receptor antagonists was explored in an effort to improve pharmacokinetics. This strategy identified piperazinone analogues that possessed improved solubility at acidic pH and increased oral bioavailability in monkeys. Further optimization led to the discovery of the clinical candidate 2-[(8R)-8-(3,5-difluorophenyl)-10-oxo-6,9-diazaspiro[4.5]dec-9-yl]-N-[(2R)-2'-oxo-1,1',2',3-tetrahydrospiro[indene-2,3'-pyrrolo[2,3-b]pyridin]-5-yl]acetamide (MK-3207) (4), the most potent orally active CGRP receptor antagonist described to date.
RESUMEN
Calcitonin gene-related peptide (CGRP) has been implicated in the pathogenesis of migraine. Replacements for the benzodiazepine core of an earlier lead structure 1 including 5-, 6-, and 7-membered lactams were explored. Within the 7-membered ring scaffold, phenyl substitution at various positions afforded the potent (3R)-amino-(6S)-phenyl caprolactam template. The phenylimidazolinone privileged structure gave additional potency enhancements, as 24 showed good potency in both CGRP binding (K(i)=2 nM) and cAMP (IC(50)=4 nM) assays and was orally bioavailable in rats (27%).
Asunto(s)
Antagonistas del Receptor Peptídico Relacionado con el Gen de la Calcitonina , Caprolactama/farmacología , Trastornos Migrañosos/tratamiento farmacológico , Administración Oral , Animales , Caprolactama/síntesis química , Caprolactama/química , Química Farmacéutica/métodos , Diseño de Fármacos , Humanos , Imidazoles/farmacología , Concentración 50 Inhibidora , Cinética , Modelos Químicos , RatasRESUMEN
High-throughput screening of the Merck sample collection identified benzodiazepinone tetralin-spirohydantoin 1 as a CGRP receptor antagonist with micromolar activity. Comparing the structure of 1 with those of earlier peptide-based antagonists such as BIBN 4096 BS, a key hydrogen bond donor-acceptor pharmacophore was hypothesized. Subsequent structure activity studies supported this hypothesis and led to benzodiazepinone piperidinyldihydroquinazolinone 7, CGRP receptor K(i)=44nM and IC(50)=38nM. Compound 7 was orally bioavailabile in rats and is a lead in the development of orally bioavailable CGRP antagonists for the treatment of migraine.
Asunto(s)
Benzodiazepinonas/farmacología , Antagonistas del Receptor Peptídico Relacionado con el Gen de la Calcitonina , Animales , Benzodiazepinonas/farmacocinética , Disponibilidad Biológica , Línea Celular , Humanos , Enlace de Hidrógeno , Ratas , Relación Estructura-ActividadRESUMEN
In our continuing effort to identify CGRP receptor antagonists for the acute treatment of migraine, we have undertaken a study to evaluate alternative 4-substituted piperidines to the lead dihydroquinazolinone 1. In this regard, we have identified the piperidinyl-azabenzimidazolone and phenylimidazolinone structures which, when incorporated into the benzodiazepine core, afford potent CGRP receptor antagonists (e.g., 18 and 29). These studies produced a potent analog (18) which overcomes the instability issues associated with the lead structure 1. A general pharmacophore for the 4-substituted piperidine component of these CGRP receptor antagonists is also presented.
Asunto(s)
Benzodiazepinas/farmacología , Antagonistas del Receptor Peptídico Relacionado con el Gen de la Calcitonina , Trastornos Migrañosos/tratamiento farmacológico , Piperidinas/farmacología , Benzodiazepinas/síntesis química , AMP Cíclico/antagonistas & inhibidores , Estabilidad de Medicamentos , Humanos , Piperidinas/síntesis química , Unión Proteica , Relación Estructura-ActividadRESUMEN
A rapid analogue approach to identification of spirohydantoin-based CGRP antagonists provided novel, low molecular weight leads. Modification of these leads afforded a series of nanomolar benzimidazolinone-based CGRP receptor antagonists. The oral bioavailability of these antagonists was inversely correlated with polar surface area, suggesting that membrane permeability was a key limitation to absorption. Optimization provided compound 12, a potent CGRP receptor antagonist (K(i)=21nM) with good oral bioavailability in three species.
Asunto(s)
Antagonistas del Receptor Peptídico Relacionado con el Gen de la Calcitonina , Hidantoínas/farmacología , Hidantoínas/farmacocinética , Compuestos de Espiro/farmacología , Compuestos de Espiro/farmacocinética , Administración Oral , Bencimidazoles/química , Bencimidazoles/farmacocinética , Bencimidazoles/farmacología , Disponibilidad Biológica , Línea Celular , Humanos , Hidantoínas/química , Riñón , Modelos Moleculares , Estructura Molecular , Compuestos de Espiro/química , Relación Estructura-ActividadRESUMEN
Compound 1 has been shown to be a dual prenylation inhibitor with FPTase (IC50=2 nM) and GGPTase-I (IC50=95 nM). Analogues of 1, which replaced the cyanophenyl group with various biaryls, led to the discovery of highly potent dual FPTase/GGPTase-I inhibitors. 4-trifluoromethylphenyl, trifluoropentynyl, and trifluoropentyl were identified as good p-cyano replacements.