RESUMO
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.
Assuntos
Inibidores do Citocromo P-450 CYP3A/química , Inibidores do Citocromo P-450 CYP3A/farmacologia , Citocromo P-450 CYP3A/metabolismo , Pirimidinas/química , Pirimidinas/farmacologia , Animais , Inibidores do Citocromo P-450 CYP3A/farmacocinética , Humanos , Cinética , Pirimidinas/farmacocinética , Ratos , Relação Estrutura-Atividade , Distribuição TecidualRESUMO
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.
Assuntos
Secretases da Proteína Precursora do Amiloide/antagonistas & inibidores , Peptídeos beta-Amiloides/metabolismo , Precursor de Proteína beta-Amiloide/metabolismo , Desenho de Fármacos , Compostos Heterocíclicos/química , Iminas/química , Peptídeos beta-Amiloides/líquido cefalorraquidiano , Animais , Córtex Cerebral/metabolismo , Inibidores Enzimáticos/farmacologia , Macaca fascicularis , Estrutura Molecular , Ratos , Relação Estrutura-AtividadeRESUMO
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.
Assuntos
Doença de Alzheimer/tratamento farmacológico , Secretases da Proteína Precursora do Amiloide/uso terapêutico , Ácido Aspártico Endopeptidases/uso terapêutico , Secretases da Proteína Precursora do Amiloide/genética , Secretases da Proteína Precursora do Amiloide/metabolismo , Animais , Ácido Aspártico Endopeptidases/genética , Ácido Aspártico Endopeptidases/metabolismo , Desenho de Fármacos , Descoberta de Drogas , Modelos Moleculares , Estrutura Molecular , Ratos , Relação Estrutura-AtividadeRESUMO
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.
Assuntos
Secretases da Proteína Precursora do Amiloide/antagonistas & inibidores , Ácido Aspártico Endopeptidases/antagonistas & inibidores , Compostos Bicíclicos Heterocíclicos com Pontes/síntese química , Nitrilas/síntese química , Pirimidinas/síntese química , Pirimidinonas/síntese química , Tiofenos/síntese química , Administração Oral , Secretases da Proteína Precursora do Amiloide/química , Peptídeos beta-Amiloides/metabolismo , Animais , Ácido Aspártico Endopeptidases/química , Compostos Bicíclicos Heterocíclicos com Pontes/farmacocinética , Compostos Bicíclicos Heterocíclicos com Pontes/farmacologia , Córtex Cerebral/metabolismo , Cristalografia por Raios X , Células HEK293 , Humanos , Macaca fascicularis , Modelos Moleculares , Conformação Molecular , Nitrilas/farmacocinética , Nitrilas/farmacologia , Fragmentos de Peptídeos/metabolismo , Permeabilidade , Pirimidinas/farmacocinética , Pirimidinas/farmacologia , Pirimidinonas/farmacocinética , Pirimidinonas/farmacologia , Teoria Quântica , Ratos , Estereoisomerismo , Relação Estrutura-Atividade , Termodinâmica , Tiofenos/farmacocinética , Tiofenos/farmacologiaRESUMO
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.
Assuntos
Doença de Alzheimer/tratamento farmacológico , Secretases da Proteína Precursora do Amiloide/antagonistas & inibidores , Peptídeos beta-Amiloides/antagonistas & inibidores , Anticonvulsivantes/síntese química , Ácido Aspártico Endopeptidases/antagonistas & inibidores , Inibidores Enzimáticos/síntese química , Hidantoínas/síntese química , Administração Oral , Doença de Alzheimer/sangue , Doença de Alzheimer/líquido cefalorraquidiano , Secretases da Proteína Precursora do Amiloide/metabolismo , Peptídeos beta-Amiloides/sangue , Peptídeos beta-Amiloides/líquido cefalorraquidiano , Animais , Anticonvulsivantes/farmacologia , Ácido Aspártico Endopeptidases/metabolismo , Sítios de Ligação , Simulação por Computador , Cristalografia por Raios X , Modelos Animais de Doenças , Desenho de Fármacos , Inibidores Enzimáticos/farmacologia , Humanos , Hidantoínas/farmacologia , Modelos Moleculares , Ligação Proteica , Ratos , Ratos Sprague-DawleyRESUMO
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.
RESUMO
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) Assuntos
Antagonistas dos Receptores Histamínicos H3/síntese química
, Antagonistas dos Receptores Histamínicos H3/farmacologia
, Piperidinas/síntese química
, Piperidinas/farmacologia
, Relação Estrutura-Atividade
RESUMO
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.
Assuntos
Secretases da Proteína Precursora do Amiloide/antagonistas & inibidores , Ácido Aspártico Endopeptidases/antagonistas & inibidores , Piperazinas/química , Inibidores de Proteases/síntese química , Sulfonamidas/química , Doença de Alzheimer/tratamento farmacológico , Secretases da Proteína Precursora do Amiloide/metabolismo , Peptídeos beta-Amiloides/antagonistas & inibidores , Peptídeos beta-Amiloides/metabolismo , Animais , Ácido Aspártico Endopeptidases/metabolismo , Sítios de Ligação , Cristalografia por Raios X , Desenho de Fármacos , Camundongos , Camundongos Transgênicos , Modelos Moleculares , Fragmentos de Peptídeos/antagonistas & inibidores , Fragmentos de Peptídeos/metabolismo , Piperazina , Inibidores de Proteases/química , Inibidores de Proteases/uso terapêutico , Relação Estrutura-Atividade , Sulfonamidas/síntese química , Sulfonamidas/uso terapêuticoRESUMO
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.
Assuntos
Secretases da Proteína Precursora do Amiloide/antagonistas & inibidores , Ácido Aspártico Endopeptidases/antagonistas & inibidores , Desenho de Fármacos , Inibidores Enzimáticos/farmacologia , Guanidinas/farmacologia , Espectroscopia de Ressonância Magnética , Bibliotecas de Moléculas Pequenas/química , Cristalografia por Raios X , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/química , Guanidinas/síntese química , Guanidinas/química , Humanos , Modelos Moleculares , Estrutura Molecular , Relação Estrutura-Atividade , Estudos de Validação como AssuntoRESUMO
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.
Assuntos
Secretases da Proteína Precursora do Amiloide/antagonistas & inibidores , Inibidores do Citocromo P-450 CYP3A , Inibidores Enzimáticos/química , Morfolinas/química , Sulfonamidas/química , Administração Oral , Secretases da Proteína Precursora do Amiloide/metabolismo , Animais , Citocromo P-450 CYP3A/metabolismo , Modelos Animais de Doenças , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/farmacocinética , Humanos , Camundongos , Camundongos Transgênicos , Morfolinas/síntese química , Morfolinas/farmacocinética , Ratos , Sulfonamidas/síntese química , Sulfonamidas/farmacocinéticaRESUMO
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.
Assuntos
Amidas/química , Amidas/farmacologia , Secretases da Proteína Precursora do Amiloide/antagonistas & inibidores , Compostos Heterocíclicos/química , Compostos Heterocíclicos/farmacologia , Inibidores de Proteases/química , Inibidores de Proteases/farmacologia , Amidas/farmacocinética , Peptídeos beta-Amiloides/metabolismo , Animais , Carbamatos/química , Carbamatos/farmacocinética , Carbamatos/farmacologia , Inibidores das Enzimas do Citocromo P-450 , Compostos Heterocíclicos/farmacocinética , Camundongos , Oxidiazóis/química , Oxidiazóis/farmacocinética , Oxidiazóis/farmacologia , Piperidinas/química , Piperidinas/farmacocinética , Piperidinas/farmacologia , Inibidores de Proteases/farmacocinética , Ratos , Relação Estrutura-AtividadeRESUMO
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.
Assuntos
Secretases da Proteína Precursora do Amiloide/antagonistas & inibidores , Piperidinas/síntese química , Piperidinas/farmacologia , Sulfonamidas/síntese química , Sulfonamidas/farmacologia , Administração Oral , Peptídeos beta-Amiloides/biossíntese , Animais , Área Sob a Curva , Sistema Enzimático do Citocromo P-450/metabolismo , Desenho de Fármacos , Espectroscopia de Ressonância Magnética , Camundongos , Conformação Molecular , Peso Molecular , Oxirredutases/metabolismoRESUMO
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.
Assuntos
Preparações Farmacêuticas/análise , Animais , Cromatografia Líquida de Alta Pressão , Estabilidade de Medicamentos , Técnicas In Vitro , Indicadores e Reagentes , Espectrometria de Massas , Microssomos Hepáticos/metabolismo , Preparações Farmacêuticas/metabolismo , RatosRESUMO
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.
Assuntos
Inibidores das Enzimas do Citocromo P-450 , Inibidores Enzimáticos/farmacologia , Antagonistas dos Receptores Histamínicos/farmacologia , Imidazóis/farmacologia , Piperidinas/farmacologia , Receptores Histamínicos H3/efeitos dos fármacos , Animais , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/química , Cobaias , Haplorrinos , Antagonistas dos Receptores Histamínicos/síntese química , Antagonistas dos Receptores Histamínicos/química , Humanos , Imidazóis/síntese química , Imidazóis/química , Estrutura Molecular , Piperidinas/síntese química , Piperidinas/química , Ratos , Relação Estrutura-Atividade , Distribuição TecidualRESUMO
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.
Assuntos
Antagonistas dos Receptores Histamínicos/farmacologia , Imidazóis/farmacologia , Piperidinas/farmacologia , Receptores Histamínicos H3/efeitos dos fármacos , Inibidores do Citocromo P-450 CYP2D6 , Avaliação Pré-Clínica de Medicamentos , Antagonistas dos Receptores Histamínicos/síntese química , Antagonistas dos Receptores Histamínicos/química , Humanos , Imidazóis/síntese química , Imidazóis/química , Técnicas In Vitro , Estrutura Molecular , Piperidinas/síntese química , Piperidinas/química , Relação Estrutura-AtividadeRESUMO
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.
Assuntos
Anti-Hipertensivos/análise , Cromatografia com Fluido Supercrítico/métodos , Pindolol/análise , Propranolol/análise , Espectrometria de Massas por Ionização por Electrospray/métodos , Animais , Pressão Atmosférica , Cromatografia com Fluido Supercrítico/instrumentação , Masculino , Microssomos Hepáticos/metabolismo , Ratos , Ratos Sprague-Dawley , EstereoisomerismoRESUMO
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.