RESUMEN
The advent of total-body positron emission tomography (PET) has vastly broadened the range of research and clinical applications of this powerful molecular imaging technology1. Such possibilities have accelerated progress in fluorine-18 (18F) radiochemistry with numerous methods available to 18F-label (hetero)arenes and alkanes2. However, access to 18F-difluoromethylated molecules in high molar activity is mostly an unsolved problem, despite the indispensability of the difluoromethyl group for pharmaceutical drug discovery3. Here we report a general solution by introducing carbene chemistry to the field of nuclear imaging with a [18F]difluorocarbene reagent capable of a myriad of 18F-difluoromethylation processes. In contrast to the tens of known difluorocarbene reagents, this 18F-reagent is carefully designed for facile accessibility, high molar activity and versatility. The issue of molar activity is solved using an assay examining the likelihood of isotopic dilution on variation of the electronics of the difluorocarbene precursor. Versatility is demonstrated with multiple [18F]difluorocarbene-based reactions including O-H, S-H and N-H insertions, and cross-couplings that harness the reactivity of ubiquitous functional groups such as (thio)phenols, N-heteroarenes and aryl boronic acids that are easy to install. The impact is illustrated with the labelling of highly complex and functionalized biologically relevant molecules and radiotracers.
Asunto(s)
Radioisótopos de Flúor , Hidrocarburos Fluorados , Tomografía de Emisión de Positrones , Radiofármacos , Ácidos Borónicos/química , Radioisótopos de Flúor/química , Hidrocarburos Fluorados/química , Imagen Molecular , Tomografía de Emisión de Positrones/métodos , Radiofármacos/químicaRESUMEN
Herein, we report a photoredox nucleophilic (radio)fluorination using TEMPO-derived alkoxyamines, a class of substrates accessible in a single step from a diversity of readily available carboxylic acids, halides, alkenes, alcohols, aldehydes, boron reagents, and C-H bonds. This mild and versatile one-electron pathway affords radiolabeled aliphatic fluorides that are typically inaccessible applying conventional nucleophilic substitution technologies due to insufficient reactivity and competitive elimination. Automation of this photoredox process is also demonstrated with a user-friendly and commercially available photoredox flow reactor and radiosynthetic platform, therefore expediting access to labeled aliphatic fluorides in high molar activity (Am) for (pre)clinical evaluation.
RESUMEN
This review describes the recent advances made in difluoromethylation processes based on X-CF2H bond formation where X is C(sp), C(sp2), C(sp3), O, N or S, a field of research that has benefited from the invention of multiple difluoromethylation reagents. The last decade has witnessed an upsurge of metal-based methods that can transfer CF2H to C(sp2) sites both in stoichiometric and catalytic mode. Difluoromethylation of C(sp2)-H bond has also been accomplished through Minisci-type radical chemistry, a strategy best applied to heteroaromatics. Examples of electrophilic, nucleophilic, radical and cross-coupling methods have appeared to construct C(sp3)-CF2H bonds, but cases of stereoselective difluoromethylation are still limited. In this sub-field, an exciting departure is the precise site-selective installation of CF2H onto large biomolecules such as proteins. The formation of X-CF2H bond where X is oxygen, nitrogen or sulfur is conventionally achieved upon reaction with ClCF2H; more recently, numerous protocols have achieved X-H insertion with novel non-ozone depleting difluorocarbene reagents. All together, these advances have streamlined access to molecules of pharmaceutical relevance, and generated interest for process chemistry.
RESUMEN
Single electron reduction is more challenging for sulfamoyl chlorides than sulfonyl chlorides. However, sulfamoyl and sulfonyl chlorides can be easily activated by Cl-atom abstraction by a silyl radical with similar rates. This latter mode of activation was therefore selected to access aliphatic sulfonamides, applying a single-step hydrosulfamoylation using inexpensive olefins, tris(trimethylsilyl)silane, and photocatalyst Eosin Y. This late-stage functionalization protocol generates molecules as complex as sulfonamide-containing cyclobutyl-spirooxindoles for direct use in medicinal chemistry.
RESUMEN
Molecular editing such as insertion, deletion, and single atom exchange in highly functionalized compounds is an aspirational goal for all chemists. Here, we disclose a photoredox protocol for the replacement of a single fluorine atom with hydrogen in electron-deficient trifluoromethylarenes including complex drug molecules. A robustness screening experiment shows that this reductive defluorination tolerates a range of functional groups and heterocycles commonly found in bioactive molecules. Preliminary studies allude to a catalytic cycle whereby the excited state of the organophotocatalyst is reductively quenched by the hydrogen atom donor, and returned in its original oxidation state by the trifluoromethylarene.
Asunto(s)
Descubrimiento de Drogas , Hidrocarburos Fluorados/síntesis química , Halogenación , Hidrocarburos Fluorados/química , Estructura Molecular , Oxidación-Reducción , Procesos FotoquímicosRESUMEN
Ammonium salts are used as phase-transfer catalysts for fluorination with alkali metal fluorides. We now demonstrate that these organic salts, specifically azetidinium triflates, are suitable substrates for enantioselective ring opening with CsF and a chiral bis-urea catalyst. This process, which highlights the ability of hydrogen bonding phase-transfer catalysts to couple two ionic reactants, affords enantioenriched γ-fluoroamines in high yields. Mechanistic studies underline the role of the catalyst for phase-transfer, and computed transition state structures account for the enantioconvergence observed for mixtures of achiral azetidinium diastereomers. The N-substituents in the electrophile influence the reactivity, but the configuration at nitrogen is unimportant for the enantioselectivity.
RESUMEN
Sulfonyl chlorides are inexpensive reactants extensively explored for functionalization, but never considered for radical hydrosulfonylation of alkenes. Herein, we report that tris(trimethylsilyl)silane is an ideal hydrogen atom donor enabling highly effective photoredox-catalyzed hydrosulfonylation of electron-deficient alkenes with sulfonyl chlorides. To increase the generality of this transformation, polarity-reversal catalysis (PRC) was successfully implemented for alkenes bearing alkyl substituents. This late-stage functionalization method tolerates a remarkably wide range of functional groups, is operationally simple, scalable, and allows access to building blocks which are important for medicinal chemistry and drug discovery.
RESUMEN
A facile method for the regioselective hydrodifluoromethylation of alkenes is reported using difluoroacetic acid and phenyliodine(III) diacetate in tetrahydrofuran under visible-light activation. This metal-free approach stands out as it uses inexpensive reagents, does not require a photocatalyst, and displays broad functional group tolerance. The procedure is also operationally simple and scalable, and provides access in one step to high-value building blocks for application in medicinal chemistry.
RESUMEN
Sulfonimidamides are an emerging bioisosteric replacement in medicinal chemistry projects, and therefore new chemistries are necessary to access this functionality. The general synthesis of CF3-sulfonimidamides from an activated bench-stable transfer reagent is described. A diverse reaction scope is demonstrated, with a wide range of nucleophilic amines being tolerated in this transformation. The CF3-sulfonimidamides obtained contain an additional diversity point, in the form a protected imine, that could be unmasked to allow late stage modifications.
RESUMEN
A general synthesis of CF3-sulfonimidamides from sulfinamides under both batch and continuous flow conditions is described. The reaction proceeds via a sulfonimidoyl fluoride intermediate. A reaction scope showing good group variation on the substituents of both nitrogen atoms is also presented.
RESUMEN
Proteochemometric modeling (PCM) is a computational approach that can be considered an extension of quantitative structure-activity relationship (QSAR) modeling, where a single model incorporates information for a family of targets and all the associated ligands instead of modeling activity versus one target. This is especially useful for situations where bioactivity data exists for similar proteins but is scarce for the protein of interest. Here we demonstrate the application of PCM to identify allosteric modulators of metabotropic glutamate (mGlu) receptors. Given our long-running interest in modulating mGlu receptor function we compiled a matrix of compound-target bioactivity data. Some members of the mGlu family are well explored both internally and in the public domain, while there are much fewer examples of ligands for other targets such as the mGlu7 receptor. Using a PCM approach mGlu7 receptor hits were found. In comparison to conventional single target modeling the identified hits were more diverse, had a better confirmation rate, and provide starting points for further exploration. We conclude that the robust structure-activity relationship from well explored target family members translated to better quality hits for PCM compared to virtual screening (VS) based on a single target.
Asunto(s)
Regulación Alostérica/efectos de los fármacos , Descubrimiento de Drogas/métodos , Relación Estructura-Actividad Cuantitativa , Receptores de Glutamato Metabotrópico/metabolismo , Secuencia de Aminoácidos , Animales , Simulación por Computador , Humanos , Ligandos , Ratones , Modelos Biológicos , Simulación del Acoplamiento Molecular , Ratas , Receptores de Glutamato Metabotrópico/agonistas , Receptores de Glutamato Metabotrópico/antagonistas & inhibidores , Receptores de Glutamato Metabotrópico/químicaRESUMEN
Novel spiroaminodihydropyrroles probing for optimized interactions at the P3 pocket of ß-secretase 1 (BACE1) were designed with the use of free energy perturbation (FEP) calculations. The resulting molecules showed pIC50 potencies in enzymatic BACE1 inhibition assays ranging from approximately 5 to 7. Good correlation was observed between the predicted activity from the FEP calculations and experimental activity. Simulations run with a default 5 ns approach delivered a mean unsigned error (MUE) between prediction and experiment of 0.58 and 0.91 kcal/mol for retrospective and prospective applications, respectively. With longer simulations of 10 and 20 ns, the MUE was in both cases 0.57 kcal/mol for the retrospective application, and 0.69 and 0.59 kcal/mol for the prospective application. Other considerations that impact the quality of the calculations are discussed. This work provides an example of the value of FEP as a computational tool for drug discovery.
Asunto(s)
Secretasas de la Proteína Precursora del Amiloide/antagonistas & inhibidores , Diseño de Fármacos , Inhibidores de Proteasas/farmacología , Amidinas/química , Secretasas de la Proteína Precursora del Amiloide/química , Modelos Moleculares , Inhibidores de Proteasas/química , Conformación Proteica , TermodinámicaRESUMEN
The synthesis of new fluorinated pyrrolidones starting from unprotected amino esters and amino nitriles through a Michael addition-lactamization sequence is described. The resulting CF3 -containing building blocks, bearing a quaternary stereogenic center adjacent to the fluorinated group, have been converted into amino pyrrolidines that display potent ß-secretase 1 (BACE1) inhibitory activity. This work constitutes an example of selective fluorination as a valid strategy for the modulation of physicochemical and biological properties of lead compounds in drug discovery.
Asunto(s)
Amidinas/síntesis química , Amidinas/farmacología , Secretasas de la Proteína Precursora del Amiloide/antagonistas & inhibidores , Secretasas de la Proteína Precursora del Amiloide/química , Ácido Aspártico Endopeptidasas/antagonistas & inhibidores , Ácido Aspártico Endopeptidasas/química , Hidrocarburos Fluorados/química , Hidrocarburos Fluorados/farmacología , Pirrolidinonas/química , Pirrolidinonas/farmacología , Ciclización , Descubrimiento de Drogas , Estructura Molecular , EstereoisomerismoRESUMEN
The synthesis of enantiomerically pure cis- and trans-2-phenyl-3-(trifluoromethyl)piperazines is described. It involved, as the key step, a diastereoselective nucleophilic addition of the Ruppert-Prakash reagent (TMSCF3) to α-amino sulfinylimines bearing Ellman's auxiliary. This methodology allows an entry into hitherto unknown trifluoromethylated and stereochemically defined piperazines, key scaffold components in medicinal chemistry.
Asunto(s)
Hidrocarburos Fluorados/química , Indicadores y Reactivos/química , Piperazinas/química , Piperazinas/síntesis química , Silanos/química , Catálisis , Descubrimiento de Drogas , Estructura Molecular , EstereoisomerismoRESUMEN
The design and synthesis of a novel series of potent gamma secretase modulators is described. Exploration of various spacer groups between the triazole ring and the aromatic appendix in 2 has led to anilinotriazole 28, which combined high in vitro and in vivo potency with an acceptable drug-like profile.
Asunto(s)
Secretasas de la Proteína Precursora del Amiloide/antagonistas & inhibidores , Compuestos de Anilina/química , Triazoles/química , Secretasas de la Proteína Precursora del Amiloide/metabolismo , Péptidos beta-Amiloides/química , Péptidos beta-Amiloides/metabolismo , Compuestos de Anilina/síntesis química , Compuestos de Anilina/metabolismo , Animales , Encéfalo/metabolismo , Diseño de Fármacos , Humanos , Ratones , Ratones Transgénicos , Unión Proteica , Relación Estructura-Actividad , Triazoles/síntesis química , Triazoles/metabolismoRESUMEN
Allosteric modulators of the metabotropic group II receptors, mGluR2 and mGluR3, have been widely explored due to their ability to modulate cognitive and neurological functions in mood disorders, although none have been approved yet. In our search for new and selective mGluR2 negative allosteric modulators (NAMs), series of 6,7-dihydropyrazolo[1,5-a]pyrazin-4(5H)-one derivatives were identified from our published series of 1,3,5-trisubstituted pyrazoles. SAR evolution of the initial hit resulted in 100-fold improvement in the mGluR2 NAM potency and subsequent selection of compound 11 based on its overall profile, including selectivity and ADMET properties. Further pharmacokinetic-pharmacodynamic (PK-PD) relationship built showed that compound 11 occupied the mGluR2 receptor in a dose-dependent manner. Additionally, the compound revealed in vivo activity in V-maze as a model of cognition from a dose of 0.32 mg/kg. Compound 11 was selected to be evaluated further.
RESUMEN
Modulation of the metabotropic glutamate type 2 (mGlu2) receptor is considered a promising target for the treatment of central nervous system diseases such as schizophrenia. Here, we describe the pharmacological properties of the novel mGlu2 receptor positive allosteric modulator (PAM) 3-cyano-1-cyclopropylmethyl-4-(4-phenyl-piperidin-1-yl)-pyridine-2(1H)-one (JNJ-40068782) and its radioligand [(3)H]JNJ-40068782. In guanosine 5'-O-(3-[(35)S]thio)triphosphate binding, JNJ-40068782 produced a leftward and upward shift in the glutamate concentration-effect curve at human recombinant mGlu2 receptors. The EC50 of JNJ-40068782 for potentiation of an EC20-equivalent concentration of glutamate was 143 nM. Although JNJ-40068782 did not affect binding of the orthosteric antagonist [(3)H]2S-2-amino-2-(1S,2S-2-carboxycyclopropyl-1-yl)-3-(xanth-9-yl)propanoic acid (LY-341495), it did potentiate the binding of the agonist [(3)H](2S,2'R,3'R)-2-(2',3'-dicarboxylcyclopropyl)glycine (DCG-IV), demonstrating that it can allosterically affect binding at the agonist recognition site. The binding of [(3)H]JNJ-40068782 to human recombinant mGlu2 receptors in Chinese hamster ovary cells and rat brain receptors was saturable with a KD of â¼10 nM. In rat brain, the anatomic distribution of [(3)H]JNJ-40068782 was consistent with mGlu2 expression previously described and was most abundant in cortex and hippocampus. The ability of structurally unrelated PAMs to displace [(3)H]JNJ-40068782 suggests that PAMs may bind to common determinants within the same site. It is noteworthy that agonists also increased the binding affinity of [(3)H]JNJ-40068782. JNJ-40068782 influenced rat sleep-wake organization by decreasing rapid eye movement sleep with a lowest active dose of 3 mg/kg PO. In mice, JNJ-40068782 reversed phencyclidine-induced hyperlocomotion with an ED50 of 5.7 mg/kg s.c. Collectively, the present data demonstrate that JNJ-40068782 has utility in investigating the potential of mGlu2 modulation for the treatment of diseases characterized by disturbed glutamatergic signaling and highlight the value of [(3)H]JNJ-40068782 in exploring allosteric binding.
Asunto(s)
Fármacos actuantes sobre Aminoácidos Excitadores/farmacología , Piperidinas/farmacología , Piridonas/farmacología , Receptores de Glutamato Metabotrópico/efectos de los fármacos , Aminoácidos/metabolismo , Animales , Autorradiografía , Unión Competitiva/efectos de los fármacos , Química Encefálica , Células CHO , Calcio/metabolismo , Membrana Celular/efectos de los fármacos , Membrana Celular/metabolismo , Corteza Cerebral/efectos de los fármacos , Corteza Cerebral/metabolismo , Cricetinae , Cricetulus , Ciclopropanos/metabolismo , Agonistas de Aminoácidos Excitadores/metabolismo , Glicina/análogos & derivados , Glicina/metabolismo , Guanosina 5'-O-(3-Tiotrifosfato)/metabolismo , Humanos , Marcaje Isotópico , Ligandos , Masculino , Ratones , Actividad Motora/efectos de los fármacos , Ratas , Ratas Sprague-Dawley , Sueño/efectos de los fármacos , Tritio , Xantenos/metabolismoRESUMEN
The synthesis, preliminary evaluation and structure-activity relationship (SAR) of a series of 1-aryl-4-methyl[1,2,4]triazolo[4,3-a]quinoxalines as dual phosphodiesterase 2/phosphodiesterase 10 (PDE2/PDE10) inhibitors are described. From this investigation compound 31 was identified, showing good combined potency, acceptable brain uptake and high selectivity for both PDE2 and PDE10 enzymes. Compound 31 was subjected to a microdosing experiment in rats, showing preferential distribution in brain areas where both PDE2 and PDE10 are highly expressed. These promising results may drive the further development of highly potent combined PDE2/PDE10 inhibitors, or even of selective inhibitors of PDE2 and/or PDE10.
Asunto(s)
Fosfodiesterasas de Nucleótidos Cíclicos Tipo 2/antagonistas & inhibidores , Descubrimiento de Drogas , Inhibidores de Fosfodiesterasa/química , Quinoxalinas/farmacología , Animales , Activación Enzimática/efectos de los fármacos , Concentración 50 Inhibidora , Masculino , Estructura Molecular , Inhibidores de Fosfodiesterasa/farmacología , Hidrolasas Diéster Fosfóricas/metabolismo , Quinoxalinas/administración & dosificación , Quinoxalinas/síntesis química , Ratas , Ratas WistarRESUMEN
The evolution of amide 3 into conformationally restricted bicyclic triazolo-piperidine 14-S as a γ-secretase modulator is described. This is a potential disease modifying anti-Alzheimer's drug which demonstrated high in vitro and in vivo potency against Aß42 peptide, reduced lipophilicity and enhanced brain free fraction compared to the previous series.
Asunto(s)
Enfermedad de Alzheimer/enzimología , Secretasas de la Proteína Precursora del Amiloide/metabolismo , Compuestos Bicíclicos Heterocíclicos con Puentes/farmacología , Diseño de Fármacos , Piperidinas/farmacología , Triazoles/farmacología , Enfermedad de Alzheimer/tratamiento farmacológico , Animales , Compuestos Bicíclicos Heterocíclicos con Puentes/química , Compuestos Bicíclicos Heterocíclicos con Puentes/metabolismo , Perros , Humanos , Ratones , Microsomas Hepáticos/metabolismo , Modelos Moleculares , Piperidinas/química , Piperidinas/metabolismo , Triazoles/química , Triazoles/metabolismoRESUMEN
The 1,2-addition of alkyl Grignard reagents to readily available N-tert-butanesulfinyl ketimines, bearing an α-silyloxy substituent, proceeds in high yields and excellent diastereocontrol. The utility of the present method was demonstrated by the synthesis, in enantiomerically pure form, of one recently disclosed ß-secretase (BACE1) inhibitor.