RESUMO
The discovery of non-symmetric thienoimidazole-containing HCV NS5A inhibitors is described. The inhibitors herein reported display high potencies against both genotype 1a and 1b. In this follow-up manuscript, we discuss the importance of the linker aromaticity to achieve high potency, particularly against genotype 1a.
Assuntos
Antivirais/farmacologia , Hepacivirus/efeitos dos fármacos , Imidazóis/farmacologia , Proteínas não Estruturais Virais/efeitos dos fármacos , Animais , Antivirais/química , Genótipo , Hepacivirus/genética , Humanos , Imidazóis/química , RatosRESUMO
The discovery of C2-symmetric bis-thienoimidazoles HCV NS5A inhibitors is herein reported. Two straightforward approaches to access the requisite diyne and biphenyl linker moieties are described. This study revealed the paramount importance of the aromatic character of the linker to achieve high genotype 1a potency.
Assuntos
Antivirais/farmacologia , Descoberta de Drogas , Imidazóis/farmacologia , Proteínas não Estruturais Virais/antagonistas & inibidores , Antivirais/química , Imidazóis/químicaRESUMO
Inhibitors of the HCV NS5A nonstructural protein are showing promising clinical potential in the treatment of hepatitis C when used in combination with other direct-acting antiviral agents. Current NS5A clinical candidates such as daclatasvir, ledipasvir, and ombitasvir share a common pharmacophore that features a pair of (S)-methoxycarbonylvaline capped pyrrolidines linked to various cores by amides, imidazoles and/or benzimidazoles. In this Letter, we describe the evaluation of NS5A inhibitors which contain alternative heteroaromatic replacements for these amide mimetics. The SAR knowledge gleaned in the optimization of scaffolds containing benzoxazoles was parlayed toward the identification of potent NS5A inhibitors containing other heteroaromatic replacements such as indoles and imidazopyridines.
Assuntos
Antivirais/síntese química , Antivirais/farmacologia , Hepacivirus/efeitos dos fármacos , Proteínas não Estruturais Virais/antagonistas & inibidores , Antivirais/química , Relação Estrutura-AtividadeRESUMO
The treatment of HCV with highly efficacious, well-tolerated, interferon-free regimens is a compelling clinical goal. Trials employing combinations of direct-acting antivirals that include NS5A inhibitors have shown significant promise in meeting this challenge. Herein, we describe our efforts to identify inhibitors of NS5A and report on the discovery of benzimidazole-containing analogs with subnanomolar potency against genotype 1a and 1b replicons. Our SAR exploration of 4-substituted pyrrolidines revealed that the subtle inclusion of a 4-methyl group could profoundly increase genotype 1a potency in multiple scaffold classes.
Assuntos
Antivirais/farmacologia , Benzimidazóis/farmacologia , Pirrolidinas/farmacologia , Proteínas não Estruturais Virais/efeitos dos fármacos , Antivirais/química , Benzimidazóis/química , Genótipo , Pirrolidinas/químicaRESUMO
RATIONALE: It has been proposed that the increase in the instances of idiosyncratic adverse drug reactions (IADRs) and black box warnings may be attributed to the occurrence of reactive metabolites. Consequently, a high-throughput screen for reactive metabolites formed from liver microsome extracts with added glutathione (GSH) was developed for use in the early stages of drug discovery. METHODS: To enhance sensitivity and specificity, as well as accelerate data processing, a mixture of a stable-isotope probe consisting of natural GSH (light GSH) and stable-isotope-labeled [(15) N,(13) C(2)] GSH (heavy GSH) at a ratio of 1:1 was used. Any metabolite that reacted with the GSH results in the formation of light and heavy GSH conjugates with a 3 Da difference. Employing a precursor-ion scan using negative ion electrospray ionization (ESI) corresponding to the expected fragments, signals with the appropriate ratio in the precursor ion scan are then further examined. RESULTS: The new method greatly simplifies data collection by assuming molecules containing GSH will fragment to form specific ions. As such, this approach accelerates data processing (and collection) at the risk of missing compounds that do not fragment as expected. The assay was validated with 33 diverse drugs known to form GSH conjugates, 5 drugs known to not form GSH adducts and over 100 samples containing components of the normal in vitro matrix. In all cases data collected matched the expected result. CONCLUSIONS: The observed sensitivity, specificity, and fast data processing make this assay an excellent fit for high-throughput screening of reactive metabolites in the early stages of drug discovery. This method is not intended to eliminate compounds or terminate their development. Instead, it is to bring forward molecules with one less liability and thus a greater probability of ultimate success.
Assuntos
Glutationa/análogos & derivados , Glutationa/metabolismo , Ensaios de Triagem em Larga Escala/métodos , Microssomos Hepáticos/metabolismo , Preparações Farmacêuticas/metabolismo , Espectrometria de Massas por Ionização por Electrospray/métodos , Animais , Avaliação Pré-Clínica de Medicamentos/métodos , Marcação por Isótopo/métodos , Preparações Farmacêuticas/química , Ratos , Sensibilidade e EspecificidadeRESUMO
Nigel Phillip Danielson-Ewing speaks to Sankeetha Nadarajah, Commissioning Editor.
Assuntos
Diversidade Cultural , IndústriasRESUMO
Compound 3 is a potent aminobenzimidazole urea with broad-spectrum Gram-positive antibacterial activity resulting from dual inhibition of bacterial gyrase (GyrB) and topoisomerase IV (ParE), and it demonstrates efficacy in rodent models of bacterial infection. Preclinical in vitro and in vivo studies showed that compound 3 covalently labels liver proteins, presumably via formation of a reactive metabolite, and hence presented a potential safety liability. The urea moiety in compound 3 was identified as being potentially responsible for reactive metabolite formation, but its replacement resulted in loss of antibacterial activity and/or oral exposure due to poor physicochemical parameters. To identify second-generation aminobenzimidazole ureas devoid of reactive metabolite formation potential, we implemented a metabolic shift strategy, which focused on shifting metabolism away from the urea moiety by introducing metabolic soft spots elsewhere in the molecule. Aminobenzimidazole urea 34, identified through this strategy, exhibits similar antibacterial activity as that of 3 and did not label liver proteins in vivo, indicating reduced/no potential for reactive metabolite formation.
Assuntos
Antibacterianos/síntese química , Benzimidazóis/síntese química , Inibidores Enzimáticos/síntese química , Animais , Antibacterianos/metabolismo , Benzimidazóis/metabolismo , DNA Girase/metabolismo , DNA Topoisomerase IV/antagonistas & inibidores , Desenho de Fármacos , Inibidores Enzimáticos/metabolismo , Humanos , Testes de Sensibilidade Microbiana , Microssomos Hepáticos/metabolismo , Relação Estrutura-Atividade , Inibidores da Topoisomerase II/metabolismo , Ureia/análogos & derivados , Ureia/síntese química , Ureia/metabolismoRESUMO
The discovery of potent thienoimidazole-based HCV NS5A inhibitors is herein reported. A novel method to access the thienoimidazole [5,5]-bicyclic system is disclosed. This method gave access to a common key intermediate (6) that was engaged in Suzuki or Sonogashira reactions with coupling partners bearing different linkers. A detailed study of the structure-activity relationship (SAR) of the linkers revealed that aromatic linkers with linear topologies are required to achieve high potency for both 1a and 1b HCV genotypes. Compound 20, with a para-phenyl linker, was identified as a potential lead displaying potencies of 17 and 8 pM against genotype 1a and 1b replicons, respectively.
RESUMO
The Ras/Raf/MEK/ERK signal transduction, an oncogenic pathway implicated in a variety of human cancers, is a key target in anticancer drug design. A novel series of pyrimidylpyrrole ERK inhibitors has been identified. Discovery of a conformational change for lead compound 2, when bound to ERK2 relative to antitarget GSK3, enabled structure-guided selectivity optimization, which led to the discovery of 11e, a potent, selective, and orally bioavailable inhibitor of ERK.
Assuntos
Desenho de Fármacos , MAP Quinases Reguladas por Sinal Extracelular/antagonistas & inibidores , Conformação Molecular , Inibidores de Proteínas Quinases/química , Inibidores de Proteínas Quinases/farmacologia , Pirróis/química , Pirróis/farmacologia , MAP Quinases Reguladas por Sinal Extracelular/química , Modelos Moleculares , Especificidade por SubstratoRESUMO
This paper describes the methods that were used for the preparation of gp96-associated peptides and the analysis of these peptides using mass spectrometry. A general approach for stripping, enriching, and separating peptides associated with gp96 is presented. Protocols for the demonstration of the diversity of gp96-associated peptides using mass spectrometry and the identification of these peptides using a combination of tandem mass spectrometry and protein database searching are described. Important parameters and factors that affect the outcome of the experiments are discussed.