RESUMEN
We report a versatile method for cross-coupling of NH-sulfoximines with (hetero)aryl chlorides, as well as bromide and sulfonate electrophiles, that makes use of the air-stable, commercial precatalyst (PhPAd-DalPhos)Ni(o-tol)Cl. Under optimized conditions a diverse electrophile scope is established, including the N-arylation of the pharmaceutical Clozapine. While 5 mol % Ni and 80 °C are commonly employed in this chemistry, successful examples utilizing 1 mol % Ni and/or 25 °C are presented. Competition experiments establish the superiority of NH-sulfoximine over primary sulfonamide as nucleophiles under these conditions.
RESUMEN
CDK7 associates with the 10-subunit TFIIH complex and regulates transcription by phosphorylating the C-terminal domain (CTD) of RNA polymerase II (RNAPII). Few additional CDK7 substrates are known. Here, using the covalent inhibitor SY-351 and quantitative phosphoproteomics, we identified CDK7 kinase substrates in human cells. Among hundreds of high-confidence targets, the vast majority are unique to CDK7 (i.e., distinct from other transcription-associated kinases), with a subset that suggest novel cellular functions. Transcription-associated factors were predominant CDK7 substrates, including SF3B1, U2AF2, and other splicing components. Accordingly, widespread and diverse splicing defects, such as alternative exon inclusion and intron retention, were characterized in CDK7-inhibited cells. Combined with biochemical assays, we establish that CDK7 directly activates other transcription-associated kinases CDK9, CDK12, and CDK13, invoking a "master regulator" role in transcription. We further demonstrate that TFIIH restricts CDK7 kinase function to the RNAPII CTD, whereas other substrates (e.g., SPT5 and SF3B1) are phosphorylated by the three-subunit CDK-activating kinase (CAK; CCNH, MAT1, and CDK7). These results suggest new models for CDK7 function in transcription and implicate CAK dissociation from TFIIH as essential for kinase activation. This straightforward regulatory strategy ensures CDK7 activation is spatially and temporally linked to transcription, and may apply toward other transcription-associated kinases.
Asunto(s)
Quinasas Ciclina-Dependientes/metabolismo , Modelos Biológicos , Factor de Transcripción TFIIH/metabolismo , Transcripción Genética/genética , Empalme Alternativo/genética , Supervivencia Celular/efectos de los fármacos , Quinasas Ciclina-Dependientes/antagonistas & inhibidores , Quinasas Ciclina-Dependientes/genética , Activación Enzimática/genética , Células HL-60 , Humanos , Quinasa Activadora de Quinasas Ciclina-DependientesRESUMEN
An electrochemical method to synthesize the core macrolactam of diazonamides is described. Large ring-forming dehydrogenation is initiated by anodic oxidation at a graphite surface. The reaction requires no tailoring of the substrate and occurs at ambient temperature in aqueous DMF in an undivided cell open to air. This unique chemistry has enabled a concise, scalable preparation of DZ-2384; a refined analog of diazonamide A slated for clinical development as a cancer therapeutic.
Asunto(s)
Amidas/química , Lactamas Macrocíclicas/química , Oxazoles/química , Preparaciones Farmacéuticas/química , Amidas/síntesis química , Compuestos Azo/química , Cristalografía por Rayos X , Ciclización , Grafito/química , Lactamas Macrocíclicas/síntesis química , Conformación Molecular , Oxazoles/síntesis química , Oxidación-Reducción , Propiedades de SuperficieRESUMEN
Recently, a new class of HIV reverse transcriptase (HIV-RT) inhibitors has been reported. The novel mechanism of inhibition by this class involves competitive binding to the active site of the RT enzyme and has been termed Nucleotide-Competing Reverse Transcriptase Inhibitors (NcRTIs). In this publication we describe the optimization of a novel benzofurano[3,2-d]pyrimidin-2-one series of NcRTIs. The starting point for the current study was inhibitor 2, which had high biochemical and antiviral potency but only moderate permeability in a Caco-2 assay and high B-to-A efflux, resulting in moderate rat bioavailability and low Cmax. We present herein the results and strategies we employed to optimize both the potency as well as the permeability, metabolic stability and pharmacokinetic profile of this series. One of the key observations of the present study was the importance of shielding polar functionality, at least in the context of the current chemotype, to enhance permeability. These studies led to the identification of inhibitors 39 and 45, which display sub-nanomolar antiviral potency in a p24 ELISA assay with significantly reduced efflux ratios (ratios <1.5). These inhibitors also display excellent rat pharmacokinetic profiles with high bioavailabilities and low clearance.
Asunto(s)
Antivirales/farmacología , Benzofuranos/farmacología , Transcriptasa Inversa del VIH/antagonistas & inhibidores , VIH/efectos de los fármacos , Pirimidinonas/farmacología , Inhibidores de la Transcriptasa Inversa/farmacología , Administración Oral , Animales , Antivirales/administración & dosificación , Antivirales/química , Benzofuranos/química , Disponibilidad Biológica , Células CACO-2 , Relación Dosis-Respuesta a Droga , Transcriptasa Inversa del VIH/metabolismo , Humanos , Pruebas de Sensibilidad Microbiana , Modelos Moleculares , Estructura Molecular , Pirimidinonas/administración & dosificación , Pirimidinonas/química , Ratas , Inhibidores de la Transcriptasa Inversa/administración & dosificación , Inhibidores de la Transcriptasa Inversa/química , Relación Estructura-ActividadRESUMEN
A HTS screen led to the identification of a benzofurano[3,2-d]pyrimidin-2-one core structure which upon further optimization resulted in 1 as a potent HIV-1 nucleotide competing reverse transcriptase inhibitor (NcRTI). Investigation of the SAR at N-1 allowed significant improvements in potency and when combined with the incorporation of heterocycles at C-8 resulted in potent analogues not requiring a basic amine to achieve antiviral activity. Additional modifications at N-1 resulted in 33 which demonstrated excellent antiviral potency and improved physicochemical properties.
Asunto(s)
Benzofuranos/química , Transcriptasa Inversa del VIH/antagonistas & inhibidores , Nucleótidos/química , Pirimidinonas/química , Inhibidores de la Transcriptasa Inversa/química , Células CACO-2 , Permeabilidad de la Membrana Celular/efectos de los fármacos , Transcriptasa Inversa del VIH/metabolismo , VIH-1/efectos de los fármacos , VIH-1/enzimología , Humanos , Microsomas Hepáticos/metabolismo , Nucleótidos/metabolismo , Unión Proteica , Pirimidinonas/síntesis química , Pirimidinonas/farmacología , Inhibidores de la Transcriptasa Inversa/síntesis química , Inhibidores de la Transcriptasa Inversa/farmacología , Estereoisomerismo , Relación Estructura-ActividadRESUMEN
Screening of our sample collection led to the identification of a set of benzofurano[3,2-d]pyrimidine-2-one hits acting as nucleotide-competing HIV-1 reverse transcriptase inhibitiors (NcRTI). Significant improvement in antiviral potency was achieved when substituents were introduced at positions N1, C4, C7 and C8 on the benzofuranopyrimidone scaffold. The series was optimized from low micromolar enzymatic activity against HIV-1 RT and no antiviral activity to low nanomolar antiviral potency. Further profiling of inhibitor 30 showed promising overall in vitro properties and also demonstrated that its potency was maintained against viruses resistant to the other major classes of HIV-1 RT inhibitors.
Asunto(s)
Benzofuranos/química , Transcriptasa Inversa del VIH/antagonistas & inhibidores , Nucleótidos/química , Pirimidinonas/química , Inhibidores de la Transcriptasa Inversa/química , Animales , Transcriptasa Inversa del VIH/metabolismo , VIH-1/efectos de los fármacos , VIH-1/enzimología , Humanos , Microsomas Hepáticos/metabolismo , Nucleótidos/metabolismo , Unión Proteica , Pirimidinonas/síntesis química , Pirimidinonas/farmacología , Ratas , Inhibidores de la Transcriptasa Inversa/síntesis química , Inhibidores de la Transcriptasa Inversa/farmacología , Relación Estructura-ActividadRESUMEN
A uHTS campaign led to the discovery of a 5-(5-furan-2-ylpyrazol-1-yl)-1H-benzimidazole series that inhibits assembly of HIV-1 capsid. Synthetic manipulations at N1, C2 and C16 positions improved the antiviral potency by a . The X-ray structure of 33 complexed with the capsid N-terminal domain allowed identification of major interactions between the inhibitor and the protein.
Asunto(s)
Antivirales/farmacología , Bencimidazoles/farmacología , Proteínas de la Cápside/antagonistas & inhibidores , VIH-1/efectos de los fármacos , Antivirales/síntesis química , Antivirales/química , Bencimidazoles/síntesis química , Bencimidazoles/química , Relación Dosis-Respuesta a Droga , Pruebas de Sensibilidad Microbiana , Modelos Moleculares , Estructura Molecular , Relación Estructura-ActividadRESUMEN
The discovery of a 1,5-dihydrobenzo[b][1,4]diazepine-2,4-dione series of inhibitors of HIV-1 capsid assembly is described. Synthesis of analogs of the 1,5-dihydrobenzo[b][1,4]diazepine-2,4-dione hit established structure-activity relationships. Replacement of the enamine functionality of the hit series with either an imidazole or a pyrazole ring led to compounds that inhibited both capsid assembly and reverse transcriptase. Optimization of the bicyclic benzodiazepine scaffold to include a 3-phenyl substituent led to lead compound 48, a pure capsid assembly inhibitor with improved antiviral activity.
Asunto(s)
Fármacos Anti-VIH/química , Benzodiazepinonas/química , Proteínas de la Cápside/antagonistas & inhibidores , VIH-1/efectos de los fármacos , Fármacos Anti-VIH/síntesis química , Fármacos Anti-VIH/farmacología , Benzodiazepinonas/síntesis química , Benzodiazepinonas/farmacología , Proteínas de la Cápside/metabolismo , Evaluación Preclínica de Medicamentos , Transcriptasa Inversa del VIH/antagonistas & inhibidores , Transcriptasa Inversa del VIH/metabolismo , Humanos , Imidazoles/química , Pirazoles/química , Inhibidores de la Transcriptasa Inversa/síntesis química , Inhibidores de la Transcriptasa Inversa/química , Inhibidores de la Transcriptasa Inversa/farmacología , Relación Estructura-ActividadRESUMEN
Even though few steroids are used for the treatment of leukemia, 2beta-(4-methylpiperazinyl)-5alpha-androstane-3alpha,17beta-diol (1) was recently reported for its ability to inhibit the proliferation of human leukemia HL-60 cells. With an efficient procedure that we had developed for the aminolysis of hindered steroidal epoxides, we synthesized a series of 2beta-amino-5alpha-androstane-3alpha,17beta-diol N-derivatives structurally similar to 1. Hence, the opening of 2,3alpha-epoxy-5alpha-androstan-17beta-diol with primary and secondary amines allowed the synthesis of aminosteroids with diverse length, ramification, and functionalization of the 2beta-side chain. Sixty-four steroid derivatives were tested for their capacity to inhibit the proliferation of HL-60 cells; thus obtaining first structure-activity relationship results. Ten aminosteroids with long alkyl chains (7-16 carbons) or bulky groups (diphenyl or adamantyl) have shown antiproliferative activity over 78% at 10microM and superior to that of the lead compound. The 3,3-diphenylpropylamino, 4-nonylpiperazinyl and octylamino derivatives of 5alpha-androstane-3alpha,17beta-diol inhibited the HL-60 cell growth with IC(50) of 3.1, 4.2 and 6.4microM, respectively. They were also found to induce the HL-60 cell differentiation.
Asunto(s)
Androstano-3,17-diol/síntesis química , Androstano-3,17-diol/farmacología , Leucemia Promielocítica Aguda/tratamiento farmacológico , Esteroides/síntesis química , Esteroides/farmacología , Androstano-3,17-diol/análogos & derivados , Androstano-3,17-diol/química , Diferenciación Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Ensayos de Selección de Medicamentos Antitumorales , Células HL-60 , Humanos , Concentración 50 Inhibidora , Conformación Molecular , Estereoisomerismo , Esteroides/química , Relación Estructura-Actividad , Células Tumorales CultivadasRESUMEN
The nucleophilic aromatic substitution reaction between electron-deficient aryl fluorides and terminal alkynes is shown to be efficiently promoted by sodium bis(trimethylsilyl)amide as a base. Moderate to excellent yields of 2-ethynylnitrobenzene products can be obtained under mild conditions.
Asunto(s)
Alquinos/química , Fluoruros/química , Hidrocarburos Aromáticos/química , Catálisis , Metales , Conformación Molecular , Solventes , EstereoisomerismoRESUMEN
A series of aryl thiotetrazolylacetanilides were synthesized and found to be potent inhibitors of the HIV-1 wild type and K103N/Y181C double mutant reverse transcriptases. The incorporation of an alkynyl fragment on the aniline provided inhibitors with excellent cellular activity and extensive SAR led to the identification of one inhibitor having good oral bioavailability in rats.
Asunto(s)
Acetanilidas/farmacología , Antivirales/química , Antivirales/farmacología , Transcriptasa Inversa del VIH/genética , VIH-1/efectos de los fármacos , VIH-1/genética , Acetanilidas/química , Animales , Disponibilidad Biológica , Modelos Moleculares , Estructura Molecular , Mutación , Ratas , Inhibidores de la Transcriptasa Inversa/química , Inhibidores de la Transcriptasa Inversa/farmacología , Relación Estructura-ActividadRESUMEN
Leukemia is the most common cancer affecting children. A steroid possessing a methylpiperazine nucleus was recently reported to inhibit the proliferation of HL-60 leukemia cells. To speed up the development of this promising potential new drug, we generated libraries of analogues using parallel solid-phase organic synthesis (SPOS). A 6-step sequence of reactions, starting from dihydrotestosterone, afforded a steroidal 2,3alpha-epoxide, which was selectively opened to give, after N-Fmoc protection, a diol with suitable stereochemistry. The difference of reactivity between 3alpha-OH and 17beta-OH was then used to allow the regioselective coupling of 17beta-OH to chloro-activated butyldiethylsilane polystyrene. We next generated three libraries of 2beta-piperazinyl-5alpha-androstane-3alpha,17beta-diol N-derivatives with 1, 2, or 3 levels of molecular diversity in acceptable yields and purities for our biological screening assay. Several members of these libraries were more potent than the lead compound, especially five members with a proline as the first level of diversity and a cyclohexylcarbonyl, methylbutyryl, cyclohexylacetyl, cyclopentylpropionyl, or hexanoyl as the second level of diversity. They efficiently inhibited HL-60 cell proliferation with IC50 values of 0.58, 0.66, 1.78, 1.98, and 2.57 microM, respectively. The present work demonstrates the potential of our SPOS approach for the optimization of a new class of cytotoxic agents.
Asunto(s)
Androstano-3,17-diol , Técnicas Químicas Combinatorias/métodos , Piperazinas/síntesis química , Piperazinas/farmacología , Androstano-3,17-diol/análogos & derivados , Androstano-3,17-diol/síntesis química , Androstano-3,17-diol/química , Androstano-3,17-diol/farmacología , Proliferación Celular/efectos de los fármacos , Cristalografía por Rayos X , Ensayos de Selección de Medicamentos Antitumorales , Células HL-60 , Humanos , Modelos Moleculares , Estructura Molecular , Piperazinas/química , Estereoisomerismo , Relación Estructura-ActividadRESUMEN
Optimization of benzimidazole 5-carboxamide derivatives previously identified as specific inhibitors of the NS5B polymerase of the hepatitis C virus (HCV) has led to the discovery of potent analogues that inhibit the enzyme at low-nanomolar concentrations. Greater than 800-fold improvement in potency from the original lead structure was achieved through the combined effects of conformational rigidification, molecular size extension and the identification of previously unexploited interactions. Furthermore, these inhibitors retain specificity for HCV polymerase relative to other viral and mammalian RNA polymerases.
Asunto(s)
Amidas/química , Antivirales/farmacología , Bencimidazoles/química , Inhibidores Enzimáticos/farmacología , Hepacivirus/enzimología , Proteínas no Estructurales Virales/antagonistas & inhibidores , Animales , Antivirales/química , Bencimidazoles/farmacología , Bovinos , ARN Polimerasas Dirigidas por ADN/antagonistas & inhibidores , Relación Dosis-Respuesta a Droga , Evaluación Preclínica de Medicamentos , Inhibidores Enzimáticos/química , Hepacivirus/efectos de los fármacos , Humanos , Estructura Molecular , Poliovirus/enzimología , ARN Polimerasa Dependiente del ARN/antagonistas & inhibidores , Relación Estructura-Actividad , Proteínas no Estructurales Virales/metabolismoRESUMEN
[structure: see text]. The total synthesis of cystothiazole A is described. Key steps of the synthesis include an Evans asymmetric catalytic aldol reaction, which established the required C4-C5 stereochemistry. The [2,4']-bis(thiazole) was obtained applying our methodology of electrophilic activation of amide. Semistabilized Wittig reaction between the phosphonium salt 3 and the aldehyde 2 afforded 1 in nine linear steps and 38% overall yield.