RESUMEN
The synthesis of a series of iminoheterocycles and their structure-activity relationships (SAR) as inhibitors of the aspartyl protease BACE1 will be detailed. An effort to access the S3 subsite directly from the S1 subsite initially yielded compounds with sub-micromolar potency. A subset of compounds from this effort unexpectedly occupied a different binding site and displayed excellent BACE1 affinities. Select compounds from this subset acutely lowered Aß40 levels upon subcutaneous and oral administration to rats.
Asunto(s)
Enfermedad de Alzheimer/tratamiento farmacológico , Secretasas de la Proteína Precursora del Amiloide/uso terapéutico , Ácido Aspártico Endopeptidasas/uso terapéutico , Secretasas de la Proteína Precursora del Amiloide/genética , Secretasas de la Proteína Precursora del Amiloide/metabolismo , Animales , Ácido Aspártico Endopeptidasas/genética , Ácido Aspártico Endopeptidasas/metabolismo , Diseño de Fármacos , Descubrimiento de Drogas , Modelos Moleculares , Estructura Molecular , Ratas , Relación Estructura-ActividadRESUMEN
From an initial lead 1, a structure-based design approach led to identification of a novel, high-affinity iminohydantoin BACE1 inhibitor that lowers CNS-derived Aß following oral administration to rats. Herein we report SAR development in the S3 and F' subsites of BACE1 for this series, the synthetic approaches employed in this effort, and in vivo data for the optimized compound.
Asunto(s)
Enfermedad de Alzheimer/tratamiento farmacológico , Secretasas de la Proteína Precursora del Amiloide/antagonistas & inhibidores , Péptidos beta-Amiloides/antagonistas & inhibidores , Anticonvulsivantes/síntesis química , Ácido Aspártico Endopeptidasas/antagonistas & inhibidores , Inhibidores Enzimáticos/síntesis química , Hidantoínas/síntesis química , Administración Oral , Enfermedad de Alzheimer/sangre , Enfermedad de Alzheimer/líquido cefalorraquídeo , Secretasas de la Proteína Precursora del Amiloide/metabolismo , Péptidos beta-Amiloides/sangre , Péptidos beta-Amiloides/líquido cefalorraquídeo , Animales , Anticonvulsivantes/farmacología , Ácido Aspártico Endopeptidasas/metabolismo , Sitios de Unión , Simulación por Computador , Cristalografía por Rayos X , Modelos Animales de Enfermedad , Diseño de Fármacos , Inhibidores Enzimáticos/farmacología , Humanos , Hidantoínas/farmacología , Modelos Moleculares , Unión Proteica , Ratas , Ratas Sprague-DawleyRESUMEN
A structure-activity relationship study of the lead piperazinylcarbonylpiperidine compound 3 resulted in the identification of 4-benzimidazolyl-piperidinylcarbonyl-piperidine 6h as a histamine-3 (H(3)) receptor antagonist. Additional optimization of 6h led to the identification of compounds 11i-k with K(i) Asunto(s)
Antagonistas de los Receptores Histamínicos H3/síntesis química
, Antagonistas de los Receptores Histamínicos H3/farmacología
, Piperidinas/síntesis química
, Piperidinas/farmacología
, Relación Estructura-Actividad
RESUMEN
With collaboration between chemistry, X-ray crystallography, and molecular modeling, we designed and synthesized a series of novel piperazine sulfonamide BACE1 inhibitors. Iterative exploration of the non-prime side and S2' sub-pocket of the enzyme culminated in identification of an analog that potently lowers peripheral Abeta(40) in transgenic mice with a single subcutaneous dose.
Asunto(s)
Secretasas de la Proteína Precursora del Amiloide/antagonistas & inhibidores , Ácido Aspártico Endopeptidasas/antagonistas & inhibidores , Piperazinas/química , Inhibidores de Proteasas/síntesis química , Sulfonamidas/química , Enfermedad de Alzheimer/tratamiento farmacológico , Secretasas de la Proteína Precursora del Amiloide/metabolismo , Péptidos beta-Amiloides/antagonistas & inhibidores , Péptidos beta-Amiloides/metabolismo , Animales , Ácido Aspártico Endopeptidasas/metabolismo , Sitios de Unión , Cristalografía por Rayos X , Diseño de Fármacos , Ratones , Ratones Transgénicos , Modelos Moleculares , Fragmentos de Péptidos/antagonistas & inhibidores , Fragmentos de Péptidos/metabolismo , Piperazina , Inhibidores de Proteasas/química , Inhibidores de Proteasas/uso terapéutico , Relación Estructura-Actividad , Sulfonamidas/síntesis química , Sulfonamidas/uso terapéuticoRESUMEN
A new class of 2,6-disubstituted morpholine N-arylsulfonamide gamma-secretase inhibitors was designed based on the introduction of a morpholine core in lieu or piperidine in our lead series. This resulted in compounds with improved CYP 3A4 profiles. Several analogs that were active at lowering Abeta levels in Tg CRND8 mice upon oral administration were identified.
Asunto(s)
Secretasas de la Proteína Precursora del Amiloide/antagonistas & inhibidores , Inhibidores del Citocromo P-450 CYP3A , Inhibidores Enzimáticos/química , Morfolinas/química , Sulfonamidas/química , Administración Oral , Secretasas de la Proteína Precursora del Amiloide/metabolismo , Animales , Citocromo P-450 CYP3A/metabolismo , Modelos Animales de Enfermedad , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/farmacocinética , Humanos , Ratones , Ratones Transgénicos , Morfolinas/síntesis química , Morfolinas/farmacocinética , Ratas , Sulfonamidas/síntesis química , Sulfonamidas/farmacocinéticaRESUMEN
The design of amide and heteroaryl amide isosteres as replacements for the carbamate substructure in previously disclosed 2,6-disubstituted piperidine N-arylsulfonamides is described. In several cases, amides lessened CYP liabilities in this class of gamma-secretase inhibitors. Selected compounds showed significant reduction of Abeta levels upon oral dosing in a transgenic murine model of Alzheimer's disease.
Asunto(s)
Amidas/química , Amidas/farmacología , Secretasas de la Proteína Precursora del Amiloide/antagonistas & inhibidores , Compuestos Heterocíclicos/química , Compuestos Heterocíclicos/farmacología , Inhibidores de Proteasas/química , Inhibidores de Proteasas/farmacología , Amidas/farmacocinética , Péptidos beta-Amiloides/metabolismo , Animales , Carbamatos/química , Carbamatos/farmacocinética , Carbamatos/farmacología , Inhibidores Enzimáticos del Citocromo P-450 , Compuestos Heterocíclicos/farmacocinética , Ratones , Oxadiazoles/química , Oxadiazoles/farmacocinética , Oxadiazoles/farmacología , Piperidinas/química , Piperidinas/farmacocinética , Piperidinas/farmacología , Inhibidores de Proteasas/farmacocinética , Ratas , Relación Estructura-ActividadRESUMEN
Herein we describe structure-activity relationship (SAR) and metabolite identification (Met-ID) studies that provided insight into the origin of time-dependent inhibition (TDI) of cytochrome P450 3A4 (CYP3A4) by compound 1. Collectively, these efforts revealed that bioactivation of the fluoropyrimidine moiety of 1 led to reactive metabolite formation via oxidative defluorination and was responsible for the observed TDI. We discovered that substitution at both the 4- and 6-positions of the 5-fluoropyrimidine of 1 was necessary to ameliorate this TDI as exemplified by compound 19.
Asunto(s)
Inhibidores del Citocromo P-450 CYP3A/química , Inhibidores del Citocromo P-450 CYP3A/farmacología , Citocromo P-450 CYP3A/metabolismo , Pirimidinas/química , Pirimidinas/farmacología , Animales , Inhibidores del Citocromo P-450 CYP3A/farmacocinética , Humanos , Cinética , Pirimidinas/farmacocinética , Ratas , Relación Estructura-Actividad , Distribución TisularRESUMEN
Packed-column supercritical fluid chromatography (pSFC) coupled to an atmospheric pressure chemical ionization (APCI) source and a tandem mass spectrometer (MS/MS) for rapid and simultaneous determination of clozapine, ondansetron, tolbutamide and primidone in in vitro samples was developed in support of metabolic stability experiments. The effects of the eluent flow-rate and composition as well as the nebulizer temperatures on the ionization efficiency of the analytes in positive ion mode under normal phase pSFC conditions were studied. The metabolic stability of the test drug components through microsomal incubation by the proposed pSFC-APCI/MS/MS approaches requiring approximately 1 min per samples were evaluated with respect to specificity, durability and accuracy. These metabolic stability results obtained by pSFC-MS/MS methods are in a good agreement with those obtained by fast high-performance liquid chromatography/tandem mass spectrometry (HPLC-MS/MS) method.
Asunto(s)
Preparaciones Farmacéuticas/análisis , Animales , Cromatografía Líquida de Alta Presión , Estabilidad de Medicamentos , Técnicas In Vitro , Indicadores y Reactivos , Espectrometría de Masas , Microsomas Hepáticos/metabolismo , Preparaciones Farmacéuticas/metabolismo , RatasRESUMEN
We describe successful efforts to optimize the in vivo profile and address off-target liabilities of a series of BACE1 inhibitors represented by 6 that embodies the recently validated fused pyrrolidine iminopyrimidinone scaffold. Employing structure-based design, truncation of the cyanophenyl group of 6 that binds in the S3 pocket of BACE1 followed by modification of the thienyl group in S1 was pursued. Optimization of the pyrimidine substituent that binds in the S2'-S2â³ pocket of BACE1 remediated time-dependent CYP3A4 inhibition of earlier analogues in this series and imparted high BACE1 affinity. These efforts resulted in the discovery of difluorophenyl analogue 9 (MBi-4), which robustly lowered CSF and cortex Aß40 in both rats and cynomolgus monkeys following a single oral dose. Compound 9 represents a unique molecular shape among BACE inhibitors reported to potently lower central Aß in nonrodent preclinical species.
Asunto(s)
Secretasas de la Proteína Precursora del Amiloide/antagonistas & inhibidores , Péptidos beta-Amiloides/metabolismo , Precursor de Proteína beta-Amiloide/metabolismo , Diseño de Fármacos , Compuestos Heterocíclicos/química , Iminas/química , Péptidos beta-Amiloides/líquido cefalorraquídeo , Animales , Corteza Cerebral/metabolismo , Inhibidores Enzimáticos/farmacología , Macaca fascicularis , Estructura Molecular , Ratas , Relación Estructura-ActividadRESUMEN
Benzazepines 1 and 2 (SCH 23390 and SCH 39166, respectively) are two classical benzazepine D1/D5 antagonists, with Ki values 1.4 and 1.2 nM, respectively. Compound 2 has been in human clinical trials for a variety of diseases, including schizophrenia, cocaine addition, and obesity. Both 1 and 2 displayed low plasma levels and poor oral bioavailability, due to rapid first-pass metabolism of the phenol moieties. Several heterocyclic systems containing an N-H hydrogen bond donor were synthesized and evaluated as phenol isosteres. The preference orientation of the hydrogen bond was established by comparison of analogues containing different NH vectors. Replacement of the phenol group of 2 with an indole ring generated the first potent D1/D5 antagonist 11b. Further optimization led to the synthesis of very potent benzimidazolones 19, 20 and benzothiazolone analogues 28, 29. These compounds have excellent selectivity over D2-D4 receptors, alpha2a receptor, and the 5-HT transporter. Compared to 2, these heterocyclic phenol isosteres showed much better pharmacokinetic profiles as demonstrated by rat plasma levels. In sharp contrast, similar phenolic replacements in 1 decreased the binding affinity dramatically, presumably due to a conformational change of the pendant phenyl group. However, one indazole compound 33 was identified as a potent D1/D5 ligand in this series.
Asunto(s)
Benzazepinas/síntesis química , Antagonistas de Dopamina/síntesis química , Fenoles/síntesis química , Receptores de Dopamina D1/antagonistas & inhibidores , Animales , Benzazepinas/farmacocinética , Benzazepinas/farmacología , Línea Celular , Cricetinae , Cricetulus , AMP Cíclico/biosíntesis , Antagonistas de Dopamina/farmacocinética , Antagonistas de Dopamina/farmacología , Diseño de Fármacos , Masculino , Modelos Moleculares , Fenoles/farmacocinética , Fenoles/farmacología , Ensayo de Unión Radioligante , Ratas , Ratas Sprague-Dawley , Receptores de Dopamina D5 , Relación Estructura-ActividadRESUMEN
On the basis of our observation that the biaryl substituent of iminopyrimidinone 7 must be in a pseudoaxial conformation to occupy the contiguous S1-S3 subsites of BACE1, we have designed a novel fused bicyclic iminopyrimidinone scaffold intended to favor this bioactive conformation. Strategic incorporation of a nitrogen atom in the new constrained ring allowed us to develop SAR around the S2' binding pocket and ultimately resulted in analogues with low nanomolar potency for BACE1. In particular, optimization of the prime side substituent led to major improvements in potency by displacement of two conserved water molecules from a region near S2'. Further optimization of the pharmacokinetic properties of this fused pyrrolidine series, in conjunction with facile access to a rat pharmacodynamic model, led to identification of compound 43, which is an orally active, brain penetrant inhibitor that reduces Aß(40) in the plasma, CSF, and cortex of rats in a dose-dependent manner.
Asunto(s)
Secretasas de la Proteína Precursora del Amiloide/antagonistas & inhibidores , Ácido Aspártico Endopeptidasas/antagonistas & inhibidores , Compuestos Bicíclicos Heterocíclicos con Puentes/síntesis química , Nitrilos/síntesis química , Pirimidinas/síntesis química , Pirimidinonas/síntesis química , Tiofenos/síntesis química , Administración Oral , Secretasas de la Proteína Precursora del Amiloide/química , Péptidos beta-Amiloides/metabolismo , Animales , Ácido Aspártico Endopeptidasas/química , Compuestos Bicíclicos Heterocíclicos con Puentes/farmacocinética , Compuestos Bicíclicos Heterocíclicos con Puentes/farmacología , Corteza Cerebral/metabolismo , Cristalografía por Rayos X , Células HEK293 , Humanos , Macaca fascicularis , Modelos Moleculares , Conformación Molecular , Nitrilos/farmacocinética , Nitrilos/farmacología , Fragmentos de Péptidos/metabolismo , Permeabilidad , Pirimidinas/farmacocinética , Pirimidinas/farmacología , Pirimidinonas/farmacocinética , Pirimidinonas/farmacología , Teoría Cuántica , Ratas , Estereoisomerismo , Relación Estructura-Actividad , Termodinámica , Tiofenos/farmacocinética , Tiofenos/farmacologíaRESUMEN
Inhibition of BACE1 to prevent brain Aß peptide formation is a potential disease-modifying approach to the treatment of Alzheimer's disease. Despite over a decade of drug discovery efforts, the identification of brain-penetrant BACE1 inhibitors that substantially lower CNS Aß levels following systemic administration remains challenging. In this report we describe structure-based optimization of a series of brain-penetrant BACE1 inhibitors derived from an iminopyrimidinone scaffold. Application of structure-based design in tandem with control of physicochemical properties culminated in the discovery of compound 16, which potently reduced cortex and CSF Aß40 levels when administered orally to rats.
RESUMEN
A number of novel amidine containing heterocycles were designed to reproduce the unique interaction pattern, revealed by X-ray crystallography, between the BACE-1 catalytic diad and a weak NMR screening hit (3), with special attention paid to maintaining the appropriate basicity and limiting the number of H-bonding donors of these scaffolds. The iminohydantoin cores (10 and 23) were examined first and found to interact with the catalytic diad in one of two binding modes (A and B), each with the iminohydantoin core flipped 180 degrees in relation to the other. The amidine structural motif within each core forms a bidentate interaction with a different aspartic acid of the catalytic diad. Both modes reproduced a highly conserved interaction pattern between the inhibitors and the catalytic aspartates, as revealed by 3. Potent iminohydantoin BACE-1 inhibitors have been obtained, validating the molecular design as aspartyl protease catalytic site inhibitors. Brain penetrant small molecule BACE inhibitors with high ligand efficiencies have been discovered, enabling multiple strategies for further development of these inhibitors into highly potent, selective and in vivo efficacious BACE inhibitors.
Asunto(s)
Secretasas de la Proteína Precursora del Amiloide/antagonistas & inhibidores , Ácido Aspártico Endopeptidasas/antagonistas & inhibidores , Diseño de Fármacos , Inhibidores Enzimáticos/farmacología , Guanidinas/farmacología , Espectroscopía de Resonancia Magnética , Bibliotecas de Moléculas Pequeñas/química , Cristalografía por Rayos X , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/química , Guanidinas/síntesis química , Guanidinas/química , Humanos , Modelos Moleculares , Estructura Molecular , Relación Estructura-Actividad , Estudios de Validación como AsuntoRESUMEN
The design and development of a new class of small 2,6-disubstituted piperidine N-arylsulfonamide gamma-secretase inhibitors is reported. Lowering molecular weight including the use of conformational constraint led to compounds with less CYP 3A4 liability compared to early leads. Compounds active orally in lowering Abeta levels in Tg CRND8 mice were identified as potential treatments for Alzheimer's disease.
Asunto(s)
Secretasas de la Proteína Precursora del Amiloide/antagonistas & inhibidores , Piperidinas/síntesis química , Piperidinas/farmacología , Sulfonamidas/síntesis química , Sulfonamidas/farmacología , Administración Oral , Péptidos beta-Amiloides/biosíntesis , Animales , Área Bajo la Curva , Sistema Enzimático del Citocromo P-450/metabolismo , Diseño de Fármacos , Espectroscopía de Resonancia Magnética , Ratones , Conformación Molecular , Peso Molecular , Oxidorreductasas/metabolismoRESUMEN
We report the discovery of novel histamine H(3) receptor antagonists based on 4-[(1H-imidazol-4-yl)methyl]piperidine. The most potent compounds in the series (e.g., 7) result from the attachment of a substituted aniline amide to the main pharmacophore piperidine via a two-methylene linker.
Asunto(s)
Antagonistas de los Receptores Histamínicos/farmacología , Imidazoles/farmacología , Piperidinas/farmacología , Receptores Histamínicos H3/efectos de los fármacos , Inhibidores del Citocromo P-450 CYP2D6 , Evaluación Preclínica de Medicamentos , Antagonistas de los Receptores Histamínicos/síntesis química , Antagonistas de los Receptores Histamínicos/química , Humanos , Imidazoles/síntesis química , Imidazoles/química , Técnicas In Vitro , Estructura Molecular , Piperidinas/síntesis química , Piperidinas/química , Relación Estructura-ActividadRESUMEN
A novel series of histamine H3 receptor antagonists based on the 4-[(1H-imidazol-4-yl)methyl]piperidine template displaying low CYP2D6 and CYP3A4 inhibitory profiles has been identified. Structural features responsible for the reduction of P450 activity, a typical liability of 4-substituted imidazoles, have been established.
Asunto(s)
Inhibidores Enzimáticos del Citocromo P-450 , Inhibidores Enzimáticos/farmacología , Antagonistas de los Receptores Histamínicos/farmacología , Imidazoles/farmacología , Piperidinas/farmacología , Receptores Histamínicos H3/efectos de los fármacos , Animales , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/química , Cobayas , Haplorrinos , Antagonistas de los Receptores Histamínicos/síntesis química , Antagonistas de los Receptores Histamínicos/química , Humanos , Imidazoles/síntesis química , Imidazoles/química , Estructura Molecular , Piperidinas/síntesis química , Piperidinas/química , Ratas , Relación Estructura-Actividad , Distribución TisularRESUMEN
A chiral packed-column supercritical fluid chromatographic (pSFC) system coupled to tandem mass spectrometer (MS/MS) for the rapid measurements of (R,S)-propranolol and (+/-)-pindolol in metabolic stability samples was developed. The effects of the eluent flow rates and compositions, as well as of the nebulizer temperature, on the chromatographic performance and the ionization efficiency of the analytes in positive ion mode under pSFC conditions were studied. The ionization mechanism of the analytes in the CO2/methanol atmospheric pressure chemical ionization (APCI) environments with or without the use of an additive was studied. The chiral pSFC-APCI-MS/MS approach requiring approximately 2 min per sample was applied for the simultaneous determination of two pairs of racemic drugs in in vitro samples at low nanogram per milliliter concentrations.