Discovery of 2-(2-Oxo-1-phenyl-5-pyridin-2-yl-1,2-dihydropyridin-3-yl)benzonitrile (Perampanel): A Novel, Noncompetitive α-Amino-3-hydroxy-5-methyl-4-isoxazolepropanoic Acid (AMPA) Receptor Antagonist

Metal-Free Cascade Formation of C-C and C-N Bond for the Construction of 3-Cyano-2-Pyridones with Insecticidal Properties

A straightforward and efficient methodology has been developed for the synthesis of 3-cyano-2-pyridones via the C-C and C-N bond formation processes. A total of 51 diverse 3-cyano-2-pyridone derivatives were obtained in moderate to excellent yields. This reaction featured advantages such as a metal-free process, wide functional group tolerance, simple operation, and mild conditions. A plausible mechanism for the reaction was proposed. 3-cyano-2-pyridones as ricinine analogues for insecticidal properties were evaluated, and the compound 3ci (LC50 = 2.206 mg/mL) showed the best insecticidal property.

Twenty-first century antiepileptic drugs. An overview of their targets and synthetic approaches

The therapeutic use of the traditional drugs against epilepsy has been hindered by their toxicity and low selectivity. These limitations have stimulated the design and development of new generations of antiepileptic drugs. This review explores the molecular targets and synthesis of the antiepileptic drugs that have entered the market in the 21st century, with a focus on manufacturer synthesis.

Palladium-Catalyzed Weak Chelation-Assisted Site-Selective C-H Arylation of N-Aryl Pyridones via 2-fold C-H Activation

Palladium-catalyzed weak chelation-assisted oxidative cross-dehydrogenative coupling of arenes has been accomplished. The use of medicinally important pyridones as the intrinsic directing group, regioselectivity, 2-fold C-H activation, and late-stage modification of bioactive compounds are the important practical features.

Regioselective Arylation of Amidoaryne Precursors via Ag-Mediated Intramolecular Oxy-Argentation

An unprecedented silver-mediated intramolecular oxy-argentation of 3-amidoaryne precursors that quickly generates a heteroarylsilver species is developed. AgF acts as both a stoichiometric fluoride source and a reagent for the formation of a benzoxazolylsilver intermediate via aryne generation. Pd-catalyzed coupling reactions of (hetero)aryl iodides with a silver species, generated in situ, allow for the synthesis of various C7-arylated benzoxazoles. As a result, an aryl group is selectively introduced into the meta-position of 3-amidobenzyne precursors. Mechanistic studies have indicated the presence of a benzoxazolylsilver intermediate and revealed that the reaction proceeds via an intramolecular oxy-argentation process, which is initiated by a direct fluoride attack on the silyl group.

Copper-Catalyzed Regioselective Imidation of 2-Pyridones

We demonstrate a ligand- and glovebox-free regioselective direct C(3)-H imidation of 2-pyridones and also benzylic-type imidation of 2-pyridones bearing a methyl substituent employing Cu(OAc)2·H2O as the catalyst and N-fluorobenzenesulfonimide (NFSI) as an imidating reagent. A broad range of imidated 2-pyridone derivatives is made up to excellent yields. The present strategy operates well on a gram scale, and the ensuing product can be readily subjected to mono- and bis-desulfonylation reactions.

The "cesium effect" magnified: exceptional chemoselectivity in cesium ion mediated nucleophilic reactions

Chemodivergent construction of structurally distinct heterocycles from the same precursors by adjusting specific reaction parameters is an emergent area of organic synthesis; yet, understanding of the processes that underpin the reaction divergence is lacking, preventing the development of new synthetic methods by systematically harnessing key mechanistic effects. We describe herein cesium carbonate-promoted oxadiaza excision cross-coupling reactions of β-ketoesters with 1,2,3-triazine 1-oxides that form pyridones in good to high yields, instead of the sole formation of pyridines when the same reaction is performed in the presence of other alkali metal carbonates or organic bases. The reaction can be further extended to the construction of synthetically challenging pyridylpyridones. A computational study comparing the effect of cesium and sodium ions in the oxadiaza excision cross-coupling reactions reveals that the cesium-coordinated species changes the reaction preference from attack at the ketone carbonyl to attack at the ester carbon due to metal ion-specific transition state conformational accommodation, revealing a previously unexplored role of cesium ions that may facilitate the development of chemodivergent approaches to other heterocyclic systems.

Research Status, Synthesis and Clinical Application of Antiepileptic Drugs

According to the 2017 ILAE's official definition, epilepsy is a slow brain disease state characterized by recurrent episodes. Due to information released by ILAE in 2017, it can be divided into four types, including focal epilepsy, generalized epilepsy, combined generalized, and focal epilepsy, and unknown epilepsy. Since 1989, 24 new antiepileptic drugs have been approved to treat different types of epilepsy. Besides, there are a variety of antiepileptic medications under clinical monitoring. These novel antiepileptic drugs have plenty of advantages. Over the past 33 years, there have been many antiepileptic drugs on the mearket, but no one has been found that can completely cure epilepsy. In this paper, the mentioned drugs were classified according to their targets, and the essential information, and clinical studies of each drug were described. The structure-activity relationship of different chemical structures was summarized. This paper provides help for the follow-up research on epilepsy drugs.

Anticonvulsant Classes and Possible Mechanism of Actions

Epilepsy is considered one of the most common neurological disorders worldwide; it needs long-term or life-long treatment. Despite the presence of several novel antiepileptic drugs, approximately 30% patients still suffer from drug-resistant epilepsy. Subsequently, searching for new anticonvulsants with lower toxicity and better efficacy is still in paramount demand. Using target-based studies in the discovery of novel antiepileptics is uncommon owing to the insufficient information on the molecular pathway of epilepsy and complex mode of action for most of known antiepileptic drugs. In this review, we investigated the properties of anticonvulsants, types of epileptic seizures, and mechanism of action for anticonvulsants.

Base-Promoted [4 + 2] Annulation Reaction of In Situ-Generated Azadienes from N-Propargylamines with Active Methylene Compounds: Access to Highly Functionalized 2-Pyridones

A facile and efficient synthesis of structurally diversified 2-pyridones is demonstrated using the [4 + 2] annulation of in situ generated azadienes from N-propargylamines and active methylene compounds. The reaction is promoted by an inorganic base giving moderate to good yields. The developed methodology is applicable for the direct and formal synthesis of various bioactive molecules. The synthetic utility of the protocol was also illustrated by late-stage functionalization of the products.

Parkinson's disease, epilepsy, and amyotrophic lateral sclerosis-emerging role of AMPA and kainate subtypes of ionotropic glutamate receptors

Ionotropic glutamate receptors (iGluRs) mediate the majority of excitatory neurotransmission and are implicated in various neurological disorders. In this review, we discuss the role of the two fastest iGluRs subtypes, namely, α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and kainate receptors, in the pathogenesis and treatment of Parkinson's disease, epilepsy, and amyotrophic lateral sclerosis. Although both AMPA and kainate receptors represent promising therapeutic targets for the treatment of these diseases, many of their antagonists show adverse side effects. Further studies of factors affecting the selective subunit expression and trafficking of AMPA and kainate receptors, and a reasonable approach to their regulation by the recently identified novel compounds remain promising directions for pharmacological research.

Facile Synthesis of Homodimeric Protein Ligands

Many proteins exist as oligomers (homodimers, homotrimers, etc.). A proven strategy for the development of high affinity ligands for such targets is to link together two modest affinity ligands that allows the formation of a 2 : 2 (or higher-order) protein-ligand complex. We report here the discovery of a convenient, "click-like" reaction for the homodimerization of protein ligands that is efficient, operationally simple to carry out, and tolerant of many functional groups. This chemistry reduces the synthetic burden inherent in the creation of homodimeric ligands since only a single precursor is required. The utility of this strategy is demonstrated by the synthesis of homodimeric inhibitors, including PROTACs.

Access to 2-pyridinones comprising enaminonitriles via AgOAc promoted cascade reactions of thioesters with aminomethylene malononitriles

The facile synthesis of 2-pyridinones containing enaminonitriles from thioesters with aminomethylene malononitriles is achieved through an AgOAc-promoted acylation/cyclization/tautomerization cascade reaction. Control experiments reveal that AgOAc acts as a versatile promoter, activating both thioester and cyano groups while also serving as a Brønsted base in the cascade sequence. Moreover, 2-pyridinones were transformed into biologically significant 2-pyridinone-fused 2-pyrimidones with intriguing fluorescence emission properties.

Perioperative perampanel administration for early seizure prophylaxis in brain tumor patients

Background

The efficacy of perioperative prophylactic antiepileptic drug therapy in "seizure-naïve" patients with brain tumor, including glioblastoma (GBM), remains controversial. This study investigated whether perampanel (PER) is effective and safe for preventing perioperative onset of epileptic seizures, so-called early seizure, in patients with brain tumors.

Methods

Forty-five patients underwent tumor resection through craniotomy for a primary supratentorial brain tumor at Ehime University Hospital between April 2021 and July 2022. PER was administered from the 1st to the 6th day after surgery for seizure prophylaxis. Occurrence of early seizure, hematological toxicities, and various side effects were recorded on postoperative days 7 and 14. In addition, the clinical course of these patients was compared with 42 brain tumor patients under the same treatment protocol who received levetiracetam (LEV) for seizure prophylaxis between April 2017 and October 2018.

Results

In 45 patients with brain tumor, including GBM, who received PER administration, no early seizures were identified within 7 days postoperatively. No adverse drug reactions such as hematological toxicity, liver or kidney dysfunction, or exanthematous drug eruption were observed in any cases. As side effects, somnolence was reported in 14 patients (31.1%), vertigo in 3 patients (6.7%), and headache in 3 patients (6.7%). Although somnolence and vertigo were difficult to assess in the case of intraparenchymal tumors, particularly GBM, these side effects were not identified in patients with extraparenchymal tumors such as meningiomas, epidermoid cysts, and pituitary adenomas. In addition, no significant differences were identified compared to patients who received LEV.

Conclusion

The efficacy and safety of PER in preventing early seizures among patients with brain tumors were retrospectively evaluated. Perioperative administration of PER to patients with brain tumors may reduce the risk of early seizures without incurring serious side effects, showing no significant differences compared to patients who received LEV.

The Antiepileptic Drug Oxcarbazepine Inhibits the Growth of Patient-Derived Isocitrate Dehydrogenase Mutant Glioma Stem-like Cells

Patients diagnosed with isocitrate dehydrogenase mutant (IDH^mut) gliomas suffer frequently from seizures. Although the clinical course is less aggressive than that of its IDH wildtype counterpart, recent discoveries have shown that epileptic activity can promote tumor proliferation. However, it is not known if antiepileptic drugs confer additional value by inhibiting tumor growth. In this study, the antineoplastic properties of 20 FDA-approved antiepileptic drugs (AEDs) were tested in six patient-derived IDH^mut glioma stem-like cells (GSCs). Cell proliferation was assessed using the CellTiterGlo-3D assay. Two of the screened drugs (oxcarbazepine and perampanel) demonstrated an antiproliferative effect. A subsequent eight-point dose-response curve proved the dose-dependent growth inhibition for both drugs, but only oxcarbazepine reached an IC₅₀ value below 100 µM in 5/6 GSCs (mean 44.7 µM; range 17.4-98.0 µM), approximating the possible c_max for oxcarbazepine in patient serums. Furthermore, the treated GSC spheroids were 82% smaller (mean volume 1.6 nL vs. 8.7 nL; p = 0.01 (live/dead^TM fluorescence staining)), and the apoptotic events increased by more than 50% (caspase-3/7 activity; p = 0.006). Taken together, this drug screen of a large series of antiepileptic drugs identified oxcarbazepine as a potent proapoptotic drug in IDH^mut GSCs, which combines antiepileptic and antineoplastic properties to treat this seizure-prone patient population.

Rh(II)-Catalyzed Synthesis of N-Aryl 2-pyridone Using 2-Oxypyridine and Diazonaphthoquinone Via 1,6-Benzoyl Migratory Rearrangement

A Rh(II)-catalyzed simple and efficient synthesis of N-arylated 2-pyridone derivatives is described using 2-oxypyridine and diazonaphthoquinone as coupling partners. The reaction proceeds through the insertion of the nitrogen atom of the 2-oxypyridine derivative into quinoid carbene and subsequent 1,6-benzoyl migratory rearrangement. The reaction is broadened with sufficient scope and has the potential to offer axially chiral N-arylated 2-pyridone derivatives under suitable asymmetric conditions.

Rhodium-Catalyzed N-Arylation of 2-Pyridones Enabled by 1,6-Acyl Migratory Rearrangement of 2-Oxypyridines

An efficient rhodium-catalyzed dearomative rearrangement of 2-oxypyridines with quinone diazides has been developed for the direct synthesis of N-arylated pyridones, in which a novel 1,6-O-to-O rather than 1,4-O-to-C acyl rearrangement has been achieved under mild reaction conditions.

Positive and negative allosteric modulation of GluK2 kainate receptors by BPAM344 and antiepileptic perampanel

Kainate receptors (KARs) are a subtype of ionotropic glutamate receptors that control synaptic transmission in the central nervous system and are implicated in neurological, psychiatric, and neurodevelopmental disorders. Understanding the regulation of KAR function by small molecules is essential for exploring these receptors as drug targets. Here, we present cryoelectron microscopy (cryo-EM) structures of KAR GluK2 in complex with the positive allosteric modulator BPAM344, competitive antagonist DNQX, and negative allosteric modulator, antiepileptic drug perampanel. Our structures show that two BPAM344 molecules bind per ligand-binding domain dimer interface. In the absence of an agonist or in the presence of DNQX, BPAM344 stabilizes GluK2 in the closed state. The closed state is also stabilized by perampanel, which binds to the ion channel extracellular collar sites located in two out of four GluK2 subunits. The molecular mechanisms of positive and negative allosteric modulation of KAR provide a guide for developing new therapeutic strategies.

A gain-of-function GRIA2 variant associated with neurodevelopmental delay and seizures: Functional characterization and targeted treatment

α-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid-type glutamate receptors (AMPARs) are ligand-gated cationic channels formed from combinations of GluA1-4 subunits. Pathogenic variants of GRIA1-4 have been described in patients with developmental delay, intellectual disability, autism spectrum disorder, and seizures, with GRIA2 variants typically causing AMPAR loss of function. Here, we identify a novel, heterozygous de novo pathogenic missense mutation in GRIA2 (c.1928 C>T, p.A643V, NM_001083619.1) in a 1-year-old boy with epilepsy, developmental delay, and failure to thrive. We made patch-clamp recordings to compare the functional and pharmacological properties of variant and wild-type receptors expressed in HEK293 cells, with and without the transmembrane AMPAR regulatory protein γ2. This showed GluA2 A643V-containing AMPARs to exhibit a novel gain of function, with greatly slowed deactivation, markedly reduced desensitization, and increased glutamate sensitivity. Perampanel, an antiseizure AMPAR negative allosteric modulator, was able to fully block GluA2 A643V/γ2 currents, suggesting potential therapeutic efficacy. The subsequent introduction of perampanel to the patient's treatment regimen was associated with a marked reduction in seizure burden, a resolution of failure to thrive, and clear developmental gains. Our study reveals that GRIA2 disorder can be caused by a gain-of-function variant, and both predicts and suggests the therapeutic efficacy of perampanel. Perampanel may prove beneficial for patients with other gain-of-function GRIA variants.

Altered Calcium Permeability of AMPA Receptor Drives NMDA Receptor Inhibition in the Hippocampus of Murine Obesity Models

Evidence has accumulated that higher consumption of high-fat diets (HFDs) during the juvenile/adolescent period induces altered hippocampal function and morphology; however, the mechanism behind this phenomenon remains elusive. Using high-resolution structural imaging combined with molecular and functional interrogation, a murine model of obesity treated with HFDs for 12 weeks after weaning mice was shown to change in the glutamate-mediated intracellular calcium signaling and activity, including further selective reduction of gray matter volume in the hippocampus associated with memory recall disturbance. Dysregulation of intracellular calcium concentrations was restored by a non-competitive α-3-hydroxy-5-methyl-4-isoxazole propionic acid receptor (AMPAR) antagonist, followed by normalization of hippocampal volume and memory recall ability, indicating that AMPARs may serve as an attractive therapeutic target for obesity-associated cognitive decline.

Pyridone Directed Ru-Catalyzed Olefination of sp2(C-H) Bond Using Michael Acceptors: Creation of Drug Analogues

Herein, the ruthenium-catalyzed regioselective sp²(C-H) monoalkenylation of N-arylpyridones has been demonstrated, where the pyridone was utilized as a weakly coordinating directing group. Importantly, the current methodology has been effectively applied to the synthesis of many drug analogues such as pirfenidone, naproxen, ibuprofen, geraniol, umbelliferone, pregnenolone, and estrone. This methodology tolerates a wide range of functional groups and yields up to 93% yield. A six-membered ruthenium complex was also detected by HRMS.

Recent Advances of Pyridinone in Medicinal Chemistry

Pyridinones have been adopted as an important block in medicinal chemistry that could serve as hydrogen bond donors and acceptors. With the help of feasible synthesis routes via established condensation reactions, the physicochemical properties of such a scaffold could be manipulated by adjustment of polarity, lipophilicity, and hydrogen bonding, and eventually lead to its wide application in fragment-based drug design, biomolecular mimetics, and kinase hinge-binding motifs. In addition, most pyridinone derivatives exhibit various biological activities ranging from antitumor, antimicrobial, anti-inflammatory, and anticoagulant to cardiotonic effects. This review focuses on recent contributions of pyridinone cores to medicinal chemistry, and addresses the structural features and structure–activity relationships (SARs) of each drug-like molecule. These advancements contribute to an in-depth understanding of the potential of this biologically enriched scaffold and expedite the development of its new applications in drug discovery.

Glutamate receptors and synaptic plasticity: The impact of Evans and Watkins

On the occasion of the 40 year anniversary of the hugely impactful review by Richard (Dick) Evans and Jeff Watkins, we describe how their work has impacted the field of synaptic plasticity. We describe their influence in each of the major glutamate receptor subtypes: AMPARs, NMDARs, KARs and mGluRs. Particular emphasis is placed on how their work impacted our own studies in the hippocampus. For example, we describe how the tools and regulators that they identified for studying NMDARs (e.g., NMDA, D-AP5 and Mg²⁺) led to the understanding of the molecular basis of the induction of LTP. We also describe how other tools that they introduced (e.g., (1S,3R)-ACPD and MCPG) helped lead to the concept of metaplasticity.

Transition metal catalysed direct construction of 2-pyridone scaffolds through C-H bond functionalizations

Substituted 2-pyridone is one of the most frequent scaffolds among nitrogen-containing bioactive natural products, pharmaceuticals and organic materials. Besides the classical syntheses to construct this class of molecules, retrosynthetically more straightforward approaches based on transition metal catalysed C-H bond functionalizations have been explored recently. In this review, we have summarized the recent progress in the direct transition metal catalysed construction of substituted 2-pyridone scaffolds via site-selective C-H bond functionalizations.

RNA aptamers for AMPA receptors

RNA aptamers are single-stranded RNA molecules, and they are selected against a target of interest so that they can bind to and modulate the activity of the target, such as inhibiting the target activity, with high potency and selectivity. Antagonists, such as RNA aptamers, acting on AMPA receptors, a major subtype of ionotropic glutamate receptors, are potential drug candidates for treatment of a number of CNS diseases that involve excessive receptor activation and/or elevated receptor expression. Here we review the approach to discover RNA aptamers targeting AMPA receptors from a random sequence library (∼10¹⁴ sequences) through a process called systematic evolution of ligands by exponential enrichment (SELEX). As compared with small-molecule compounds, RNA aptamers are a new class of regulatory agents with interesting and desirable pharmacological properties. Some AMPA receptor aptamers we have developed are presented in this review. The promises and challenges of translating RNA aptamers into potential drugs and treatment options are also discussed. This article is part of the special Issue on 'Glutamate Receptors - AMPA receptors'.

Nitrile-containing pharmaceuticals: target, mechanism of action, and their SAR studies

The nitrile group is an important functional group widely found in both pharmaceutical agents and natural products. More than 30 nitrile-containing pharmaceuticals have been approved by the FDA for the management of a broad range of clinical conditions in the last few decades. Incorporation of a nitrile group into lead compounds has gradually become a promising strategy in rational drug design as it can bring additional benefits including enhanced binding affinity to the target, improved pharmacokinetic profile of parent drugs, and reduced drug resistance. This paper reviews the existing drugs with a nitrile moiety that have been approved or in clinical trials, involving their targets, molecular mechanism of pharmacology and SAR studies, and classifies them into different categories based on their clinical usages.

Single-channel mechanisms underlying the function, diversity and plasticity of AMPA receptors

The functional properties of AMPA receptors shape many of the essential features of excitatory synaptic signalling in the brain, including high-fidelity point-to-point transmission and long-term plasticity. Understanding the behaviour and regulation of single AMPAR channels is fundamental in unravelling how central synapses carry, process and store information. There is now an abundance of data on the importance of alternative splicing, RNA editing, and phosphorylation of AMPAR subunits in determining central synaptic diversity. Furthermore, auxiliary subunits have emerged as pivotal players that regulate AMPAR channel properties and add further diversity. Single-channel studies have helped reveal a fascinating picture of the unique behaviour of AMPAR channels - their concentration-dependent single-channel conductance, the basis of their multiple-conductance states, and the influence of auxiliary proteins in controlling many of their gating and conductance properties. Here we summarize basic hallmarks of AMPAR single-channels, in relation to function, diversity and plasticity. We also present data that reveal an unexpected feature of AMPAR sublevel behaviour. This article is part of the special Issue on 'Glutamate Receptors - AMPA receptors'.

Structure, Function, and Pharmacology of Glutamate Receptor Ion Channels

Many physiologic effects of l-glutamate, the major excitatory neurotransmitter in the mammalian central nervous system, are mediated via signaling by ionotropic glutamate receptors (iGluRs). These ligand-gated ion channels are critical to brain function and are centrally implicated in numerous psychiatric and neurologic disorders. There are different classes of iGluRs with a variety of receptor subtypes in each class that play distinct roles in neuronal functions. The diversity in iGluR subtypes, with their unique functional properties and physiologic roles, has motivated a large number of studies. Our understanding of receptor subtypes has advanced considerably since the first iGluR subunit gene was cloned in 1989, and the research focus has expanded to encompass facets of biology that have been recently discovered and to exploit experimental paradigms made possible by technological advances. Here, we review insights from more than 3 decades of iGluR studies with an emphasis on the progress that has occurred in the past decade. We cover structure, function, pharmacology, roles in neurophysiology, and therapeutic implications for all classes of receptors assembled from the subunits encoded by the 18 ionotropic glutamate receptor genes. SIGNIFICANCE STATEMENT: Glutamate receptors play important roles in virtually all aspects of brain function and are either involved in mediating some clinical features of neurological disease or represent a therapeutic target for treatment. Therefore, understanding the structure, function, and pharmacology of this class of receptors will advance our understanding of many aspects of brain function at molecular, cellular, and system levels and provide new opportunities to treat patients.

Synthesis of 1-(1-Arylvinyl)pyridin-2(1H)-ones from Ketones and 2-Fluoropyridine

We describe a simple and efficient procedure for the synthesis of N-vinyl-substituted pyridones from ketones and 2-fluoropyridine in the presence of trifluoromethane sulfonic anhydride, followed by a base treatment. Various ketones with electron-donating or electron-withdrawing groups at the benzene rings can be used in this reaction. A preliminary mechanistic study indicates that it is not very likely that both vinyl triflates and vinyl cations play major roles as intermediates in this transformation.

Clinical effects and outcomes of perampanel overdoses reported to U.S. poison centers

INTRODUCTION

Perampanel is indicated for partial onset seizures in children and adults. The mechanism is unique among antiepileptic agents as it inhibits glutamate activity on AMPA receptors. Currently, there are few published case reports describing overdose.

METHODS

This is a retrospective observational study of all single substance perampanel ingestions from January 2014 to December 2019 reported to the national poison data system (NPDS). The primary outcome is to describe the clinical effects of perampanel exposures. Secondary outcomes include evaluation of management and investigation of a dose-effect relationship for the purpose of triaging acute unintentional exposures.

RESULTS

A total of 138 exposures were reported to NPDS since the release of the agent. Median age was 20 years (IQR 10-38) with 68 (49.3%) males. The reason for exposure was most commonly therapeutic error (80, 58.0%), followed by exploratory ingestion (24, 17.4%), and suicidal ingestion (14, 10.1%). A total of six (4.3%) patients developed major effects, 20 (14.5%) moderate, 32 (23.2%) minor effects and 22 (15.9%) no effect. An additional 54 (39.1%) cases were not followed. Almost half of cases were managed at home. Of those that were in a healthcare facility (HCF) (n = 72), most were treated/evaluated and released (31, 43.1%), followed by admission to a non-critical care unit (20, 27.8%), and critical care unit (13, 18.1%). Most frequently reported symptoms were drowsiness (27, 19.6%), agitation (20, 14.5%), ataxia (13, 9.4%), and confusion (12, 8.7%). The most common therapies provided in a HCF were intravenous fluids (22,30.6%), followed by benzodiazepines (14, 19.4%), then other types of sedation (9, 12.5%). There were too few cases to determine a dose cut off for triaging.

CONCLUSIONS

While drowsiness, agitation, ataxia, and confusion were the most often reported symptoms, close to 19% developed moderate/major effects and almost 4% of patients received potentially life-saving interventions.

RhIII -Catalyzed C6-Selective Oxidative C-H/C-H Crosscoupling of 2-Pyridones with Thiophenes

A rhodium(III)-catalyzed C6-selective dehydrogenative cross-coupling of 2-pyridones with thiophenes was developed for the synthesis of 6-thiophenyl pyridin-2(1H)-one derivatives. In this reaction, the excellent site selectivity was controlled by the 2-pyridyl directing group on the nitrogen of the pyridone ring. Control experiments indicated that the N-pyridyl was essential for the transformation. To the best of our knowledge, this procedure is the first successful example of the direct C6 heteroarylation of 2-pyridones with electron-rich thiophene derivatives. 4-Pyridone was also used as substrate to generate the corresponding C2 heteroarylated product. Moreover, this pyridyl directing group was readily removable to generate the biheteroaryl structures with a free N-H group.

Stability Indicating Methods for Determination of Third Generation Antiepileptic Drugs and Their Related Substances

The third generation of antiepileptic drugs that have been approved by international regulatory agencies between 2007 and 2018 include rufinamide, stiripentol, eslicarbazepine acetate, lacosamide, perampanel, brivaracetam and everolimus. As part of demonstrating their safety profile, stability indicating methods are developed to monitor these drugs and their impurities. In this context, this review describe some characteristics, impurities and the stability indicating methods used for the determination of these drugs and the presence of their related substances. Through a search in official compendia and scientific articles, fifty-six analytical methodologies were identified up to October 2020. The methodologies were developed using techniques of HPLC, UPLC, HPTLC, GC and UV/Vis spectrophotometry. A majority of the methods (∼70%) employed HPLC-UV. A number of these antiepileptic drugs were found to have had a small number of studies related to their stability and for the detection of impurities. The presentation of the current level of research on third generation antiepileptic drugs highlights the need for new stability and safety studies that are necessary to develop new pharmaceutical products containing these drugs.

Construction of 2-pyridones via oxidative cyclization of enamides: access to Pechmann dye derivatives

An efficient protocol for the construction of structurally diverse 2-pyridone derivatives from imines and α,β-unsaturated acid chlorides in a single operation is reported. The target compounds, including coumarin-8-oxoprotoberbine analogues and lamellarin G isomers, were prepared via thermal cyclization of the in situ generated enamides followed by thermal dehydrogenation. The cyclization of enamides was achieved by the introduction of an electron-withdrawing group on the α-carbon of acid chlorides. This methodology allows quick access to polycyclic Pechmann dyes via rare double oxidative cyclizations of dienamides under mild conditions.

Rhodium-Catalyzed C4-Selective C-H Alkenylation of 2-Pyridones by Traceless Directing Group Strategy

A rhodium-catalyzed C4-selective C-H alkenylation of 3-carboxy-2-pyridones with styrenes has been developed. The carboxylic group at the C3 position works as the traceless directing group, and the corresponding C4-alkenylated 2-pyridones are obtained exclusively with concomitant decarboxylation. Unlike the reported procedures, the exclusive C4 selectivity is uniformly observed even in the presence of potentially more reactive C-H bonds at the C5 and C6 positions. By using this strategy, the multiply substituted 2-pyridone can be prepared via sequential C-H functionalization reactions.

The AMPAR antagonist perampanel protects the neurovascular unit against traumatic injury via regulating Sirt3

Introduction

Perampanel is a highly selective and noncompetitive α‐amino‐3 ‐hydroxy‐5‐methyl‐4‐isoxazole propionate receptor (AMPAR) antagonist, which has been used as an orally administered antiepileptic drug in more than 55 countries. Recently, perampanel was shown to exert neuroprotective effects in hemorrhagic and ischemic stroke models via regulating blood–brain barrier (BBB) function.

Aim

Here, the protective effects of perampanel were investigated in an in vitro neurovascular unit (NVU) system established using a triple cell co‐culture model (neurons, astrocytes, and brain microvascular endothelial cells) and in an in vivo traumatic brain injury (TBI) model.

Results

Neurons in the NVU system exhibit a more mature morphological phenotype compared with neurons cultured alone, and the co‐culture system mimicked an impermeable barrier in vitro. Perampanel protects the NVU system against traumatic and excitotoxic injury, as evidenced by reduced lactate dehydrogenase (LDH) release and apoptotic rate. Treatment with perampanel attenuated lipid peroxidation and expression of inflammatory cytokines. In addition, perampanel increased Sirt3 protein expression, enhanced the activities of mitochondrial enzyme IDH2 and SOD2, and preserved BBB function in vitro. Knockdown of Sirt3 using specific siRNA (Si‐Sirt3) partially reserved the effects of perampanel on neuronal injury and BBB function. Treatment with perampanel in vivo attenuated brain edema, preserved neurological function, inhibited apoptosis and microglia activation after TBI. Furthermore, perampanel increased the expression of Sirt3 and preserved BBB function after TBI. The effect of perampanel on BBB function and brain edema was abolished by knockdown of Sirt3 in vivo.

Conclusion

Our results indicate that the noncompetitive AMPAR antagonist perampanel protects the NVU system and reduces brain damage after TBI via activating the Sirt3 cascades.

Clmp Regulates AMPA and Kainate Receptor Responses in the Neonatal Hippocampal CA3 and Kainate Seizure Susceptibility in Mice

Synaptic adhesion molecules regulate synapse development through trans-synaptic adhesion and assembly of diverse synaptic proteins. Many synaptic adhesion molecules positively regulate synapse development; some, however, exert negative regulation, although such cases are relatively rare. In addition, synaptic adhesion molecules regulate the amplitude of post-synaptic receptor responses, but whether adhesion molecules can regulate the kinetic properties of post-synaptic receptors remains unclear. Here we report that Clmp, a homophilic adhesion molecule of the Ig domain superfamily that is abundantly expressed in the brain, reaches peak expression at a neonatal stage (week 1) and associates with subunits of AMPA receptors (AMPARs) and kainate receptors (KARs). Clmp deletion in mice increased the frequency and amplitude of AMPAR-mediated miniature excitatory post-synaptic currents (mEPSCs) and the frequency, amplitude, and decay time constant of KAR-mediated mEPSCs in hippocampal CA3 neurons. Clmp deletion had minimal impacts on evoked excitatory synaptic currents at mossy fiber-CA3 synapses but increased extrasynaptic KAR, but not AMPAR, currents, suggesting that Clmp distinctly inhibits AMPAR and KAR responses. Behaviorally, Clmp deletion enhanced novel object recognition and susceptibility to kainate-induced seizures, without affecting contextual or auditory cued fear conditioning or pattern completion-based contextual fear conditioning. These results suggest that Clmp negatively regulates hippocampal excitatory synapse development and AMPAR and KAR responses in the neonatal hippocampal CA3 as well as object recognition and kainate seizure susceptibility in mice.

An efficient method for the synthesis of 2-pyridones via C-H bond functionalization

A simple and practical method to access N-substituted 2-pyridones via a formal [3+3] annulation of enaminones with acrylates based on RhIII-catalyzed C-H functionalization was developed. Control and deuterated experiments led to a plausible mechanism involving C-H bond cross-coupling and aminolysis cyclization. This strategy provides a short synthesis of structural motifs of N-substituted 2-pyridones.

Discovery of a Potent and Selective PI3Kδ Inhibitor (S)-2,4-Diamino-6-((1-(7-fluoro-1-(4-fluorophenyl)-4-oxo-3-phenyl-4H-quinolizin-2-yl)ethyl)amino)pyrimidine-5-carbonitrile with Improved Pharmacokinetic Profile and Superior Efficacy in Hematological Cancer Models

PI3Kδ inhibitors have been approved for B-cell malignancies like CLL, small lymphocytic lymphoma, and so forth. However, currently available PI3Kδ inhibitors are nonoptimal, showing weakness against at least one of the several important properties: potency, isoform selectivity, and/or pharmacokinetic profile. To come up with a PI3Kδ inhibitor that overcomes all these deficiencies, a pharmacophoric expansion strategy was employed. Herein, we describe a systematic transformation of a "three-blade propeller" shaped lead, 2,3-disubstituted quinolizinone 11, through a 1,2-disubstituted quinolizinone 20 to a novel "four-blade propeller" shaped 1,2,3-trisubstituted quinolizinone 34. Compound 34 has excellent potency, isoform selectivity, metabolic stability across species, and exhibited a favorable pharmacokinetic profile. Compound 34 also demonstrated a differentiated efficacy profile in human germinal center B and activated B cell-DLBCL cell lines and xenograft models. Compound 34 qualifies for further evaluation as a candidate for monotherapy or in combination with other targeted agents in DLBCLs and other forms of iNHL.

Age-dependent anticonvulsant actions of perampanel and brivaracetam in the methyl-6,7-dimethoxy-4-ethyl-beta-carboline-3-carboxylate (DMCM) model of seizures in developing rats

BACKGROUND

The antiseizure drugs commonly used as first- and second-line treatments for neonatal seizures display poor efficacy. Thus, drug mechanisms of action that differ from these typical agents might provide better seizure control. Perampanel, an AMPA-receptor antagonist, and brivaracetam, a SV2A ligand, might fill that role.

METHODS

We utilized methyl-6,7-dimethoxy-4-ethyl-beta-carboline-3-carboxylate (DMCM) to evoke seizures in rats to assess the efficacy of perampanel and brivaracetam treatment in clinically relevant doses.

RESULTS

In postnatal day (P)10 rats, neither perampanel nor brivaracetam suppressed seizure activity. By contrast, in P21 rats, both drugs decreased the severity of seizures. This effect was evident at the 20 and 40 mg/kg doses of brivaracetam and at the 0.9 and 2.7 mg/kg doses of perampanel.

CONCLUSIONS

These data indicate that while the efficacy of these drugs may be limited for neonatal seizures, their efficacy increases over early postnatal development.

Identification of epilepsy-associated neuronal subtypes and gene expression underlying epileptogenesis

Epilepsy is one of the most common neurological disorders, yet its pathophysiology is poorly understood due to the high complexity of affected neuronal circuits. To identify dysfunctional neuronal subtypes underlying seizure activity in the human brain, we have performed single-nucleus transcriptomics analysis of >110,000 neuronal transcriptomes derived from temporal cortex samples of multiple temporal lobe epilepsy and non-epileptic subjects. We found that the largest transcriptomic changes occur in distinct neuronal subtypes from several families of principal neurons (L5-6_Fezf2 and L2-3_Cux2) and GABAergic interneurons (Sst and Pvalb), whereas other subtypes in the same families were less affected. Furthermore, the subtypes with the largest epilepsy-related transcriptomic changes may belong to the same circuit, since we observed coordinated transcriptomic shifts across these subtypes. Glutamate signaling exhibited one of the strongest dysregulations in epilepsy, highlighted by layer-wise transcriptional changes in multiple glutamate receptor genes and strong upregulation of genes coding for AMPA receptor auxiliary subunits. Overall, our data reveal a neuronal subtype-specific molecular phenotype of epilepsy.

The pathophysiology of epilepsy is unclear. Here, the authors present single-nuclei transcriptomic profiling of human temporal lobe epilepsy from patients. They identified epilepsy-associated neuronal subtypes, and a panel of dysregulated genes, predicting neuronal circuits contributing to epilepsy.

Perampanel reduces paroxysmal depolarizing shift and inhibitory synaptic input in excitatory neurons to inhibit epileptic network oscillations

BACKGROUND AND PURPOSE

Perampanel is a newly approved anticonvulsant uniquely targeting AMPA receptors, which mediate the most abundant form of excitatory synaptic transmission in the brain. However, the network mechanism underlying the anti-epileptic effect of the AMPAergic inhibition remains to be explored.

EXPERIMENTAL APPROACH

The mechanism of perampanel action was studied with the basolateral amygdala network containing pyramidal-inhibitory neuronal resonators in seizure models of 4-aminopyridine (4-AP) and electrical kindling.

KEY RESULTS

Application of either 4-AP or electrical kindling to the basolateral amygdala readily induces AMPAergic transmission-dependent reverberating activities between pyramidal-inhibitory neuronal resonators, which are chiefly characterized by burst discharges in inhibitory neurons and corresponding recurrent inhibitory postsynaptic potentials in pyramidal neurons. Perampanel reduces post-kindling "paroxysmal depolarizing shift" especially in pyramidal neurons and, counterintuitively, eliminates burst activities in inhibitory neurons and inhibitory synaptic inputs onto excitatory pyramidal neurons to result in prevention of epileptiform discharges and seizure behaviours. Intriguingly, similar effects can be obtained with not only the AMPA receptor antagonist CNQX but also the GABA_A receptor antagonist bicuculline, which is usually considered as a proconvulsant.

CONCLUSION AND IMPLICATIONS

Ictogenesis depends on the AMPA receptor-dependent recruitment of pyramidal-inhibitory neuronal network oscillations tuned by dynamic glutamatergic and GABAergic transmission. The anticonvulsant effect of perampanel then stems from disruption of the coordinated network activities rather than simply decreased neuronal excitability or excitatory transmission. Positive or negative modulation of epileptic network reverberations may be pro-ictogenic or anti-ictogenic, respectively, constituting a more applicable rationale for the therapy against seizures.