3,4-dihydro-2(1H)-quinolinone as a novel antidepressant drug: synthesis and pharmacology of 1-[3-[4-(3-chlorophenyl)-1-piperazinyl]propyl]-3,4- dihydro-5-methoxy-2(1H)-quinolinone and its derivatives

Construction of 3,4-Dihydroquinolone Derivatives through Pd-Catalyzed [4+2] Cycloaddition of Vinyl Benzoxazinanones with α-Alkylidene Succinimides

The construction of 3,4-dihydroquinolone derivatives has attracted a considerable amount of attention due to their extensive applications in medicinal chemistry. In this study, we present the Pd-catalyzed [4+2] cycloaddition of vinyl benzoxazinanones with α-alkylidene succinimides for the efficient synthesis of 3,4-dihydroquinolones. This approach presents numerous advantages, including the ready availability of starting materials, mild reaction conditions without the use of additional bases, and a wide range of substrates. In particular, all of the desired products can be easily afforded in high yields (≤99%) and excellent diastereoselectivities (>20:1). The practicality and reliability of this strategy were demonstrated by the successful scale-up synthesis and subsequent straightforward synthetic transformations.

Dehydrogenative Electrochemical Synthesis of N-Aryl-3,4-Dihydroquinolin-2-ones by Iodine(III)-Mediated Coupling Reaction

Electrochemically generated hypervalent iodine(III) species are powerful reagents for oxidative C-N coupling reactions, providing access to valuable N-heterocycles. A new electrocatalytic hypervalent iodine(III)-mediated in-cell synthesis of 1H-N-aryl-3,4-dihydroquinolin-2-ones by dehydrogenative C-N bond formation is presented. Catalytic amounts of the redox mediator, a low supporting electrolyte concentration and recycling of the solvent used make this method a sustainable alternative to electrochemical ex-cell or conventional approaches. Furthermore, inexpensive, readily available electrode materials and a simple galvanostatic set-up are applied. The broad functional group tolerance could be demonstrated by synthesizing 23 examples in yields up to 96 %, with one reaction being performed on a 10-fold higher scale. Based on the obtained results a sound reaction mechanism could be proposed.

Novel quinolin-2(1H)-one analogues as potential fungicides targeting succinate dehydrogenase: design, synthesis, inhibitory evaluation and molecular modeling

BACKGROUND

Succinate dehydrogenase is an important target of fungicides. Succinate dehydrogenase inhibitors (SDHIs) have widely been used to combat destructive plant pathogenic fungi because they possess efficient and broad-spectrum antifungal activities and as well as unique mode of action. The research and development of novel SDHIs have been ongoing.

RESULTS

Thirty-six novel quinolin-2(1H)-one derivatives were designed, synthesized and characterized. The single crystal structure of compound 3c was determined through the X-ray diffraction of single crystals. The bioassay results displayed that most compounds had good antifungal activities at 16 μg mL-1 against Rhizoctonia cerealis, Erysiphe graminis, Botrytis cinerea, Penicillium italicum and Phytophthora infestans. Compounds 6o, 6p and 6r had better antifungal activities than the commercialized fungicide pyraziflumid against Botrytis cinerea. Their half maximal effective concentration (EC50 ) values were 0.398, 0.513, 0.205 and 0.706 μg mL-1 , respectively. Moreover, the inhibiting activities of the bioactive compounds were tested against succinate dehydrogenase. The results indicated that they possessed outstanding activities. Compounds 6o, 6p and 6r also exhibited better inhibiting activities than pyraziflumid against succinate dehydrogenase. Their half maximal inhibitory concentration (IC50 ) values were 0.450, 0.672, 0.232 and 0.858 μg mL-1 , respectively. The results of molecular dynamic (MD) simulations indicated that compound 6r displayed stronger affinity to succinate dehydrogenase than pyraziflumid.

CONCLUSION

The results of the present study displayed that quinolin-2(1H)-one derivative could be one scaffold of potential SDHIs and will provide some valuable information for the research and development of new SDHIs. © 2022 Society of Chemical Industry.

Psoralea corylifolia (babchi) seeds enhance proliferation of normal human cultured melanocytes: GC–MS profiling and biological investigation

Plants are considered as a source of medicine to treat skin-related disorders since decades. Seeds of Psoralea corylifolia were used thousands of years ago for re-pigmentation in vitiligo patients especially in South Asia. It is a well-known fact that melanocytes, which are the specialized cells in the skin causes vitiligo through a series of chemical and enzymatic reactions, mainly due to the copper containing enzyme tyrosinase. Conditions associated with overproduction of melanin are termed hyperpigmentation. The treatment options are generally limited due to the complicated and slow pathogenesis of the disease. Therefore, therapeutic repigmentation modalities for the treatment of vitiligo are highly desirable. The aim of this study was to investigate the effects of various doses of ethanol and water extracts of P. corylifolia seeds on proliferation of normal human cultured melanocytes and its gas chromatography–mass spectrometry profiling.

Design, Synthesis, and Pharmacology of New Triazole-Containing Quinolinones as CNS Active Agents

Epilepsy and major depressive disorder are the two of the most common central nervous system (CNS) diseases. Clinicians and patients call for new antidepressants, antiseizure medicines, and in particular drugs for depression and epilepsy comorbidities. In this work, a dozen new triazole-quinolinones were designed, synthesized, and investigated as CNS active agents. All compounds reduced the immobility time significantly during the forced swim test (FST) in mice at the dosage of 50 mg/kg. Compounds 3f-3j gave superior performance over fluoxetine in the FST with more reductions of the immobility time. Compound 3g also reduced immobility time significantly in a tail suspension test (TST) at the dosage of 50 mg/kg, though its anti-immobility activity was inferior to that of fluoxetine. An open field test was carried out and it eliminated the false-positive possibility of 3g in the FST and TST, which complementarily supported the antidepressant activity of 3g. We also found that almost all compounds except 3k exhibited antiseizure activity in the maximal electroshock seizure (MES) model at 100 or 300 mg/kg. Compounds 3c, 3f, and 3g displayed the ED₅₀ of 63.4, 78.9, and 84.9 mg/kg, and TD₅₀ of 264.1, 253.5, and 439.9 mg/kg, respectively. ELISA assays proved that the mechanism for the antiseizure and antidepressant activities of compound 3g was via affecting the concentration of GABA in mice brain. The molecular docking study showed a good interaction between 3g and the amino acid residue of the GABA_A receptor. Excellent drug-like properties and pharmacokinetic properties of compound 3a-l were also predicted by Discovery Studio. These findings provided a new skeleton to develop agents for the treatment of epilepsy and depression comorbidities.

Highly Potent and Selective Dopamine D4 Receptor Antagonists Potentially Useful for the Treatment of Glioblastoma

To better understand the role of dopamine D₄ receptor (D₄R) in glioblastoma (GBM), in the present paper, new ligands endowed with high affinity and selectivity for D₄R were discovered starting from the brain penetrant and D₄R selective lead compound 1-(3-(4-phenylpiperazin-1-yl)propyl)-3,4-dihydroquinolin-2(1H)-one (6). In particular, the D₄R antagonist 24, showing the highest affinity and selectivity over D₂R and D₃R within the series (D₂/D₄ = 8318, D₃/D₄ = 3715), and the biased ligand 29, partially activating D₄R G_i-/G_o-protein and blocking β-arrestin recruitment, emerged as the most interesting compounds. These compounds, evaluated for their GBM antitumor activity, induced a decreased viability of GBM cell lines and primary GBM stem cells (GSC#83), with the maximal efficacy being reached at a concentration of 10 μM. Interestingly, the treatment with both compounds 24 and 29 induced an increased effect in reducing the cell viability with respect to temozolomide, which is the first-choice chemotherapeutic drug in GBM.

Selective Reduction of Quinolinones Promoted by a SmI2/H2O/MeOH System

The selective reduction of quinolin-2(1H)-ones promoted by a SmI₂/H₂O/MeOH system is reported for the first time. The reaction is effectively carried out to afford 3,4-dihydroquinoline-2(1H)-ones under mild conditions in a one-pot fashion with good to excellent yields.

Electronic Relaxation Dynamics in 2-Quinolinones with Extended Conjugation

The 2-quinolinone family of molecules, also known as carbostyrils, have been proposed as light absorbing donor molecules in energy transfer based sensing schemes and as possible photocatalysts. Both of these applications make use of electronic excited states, but the photophysics of 2-quinolinones have not yet been examined closely. This study applies static and dynamic spectroscopy, with supporting density functional theory calculations, to reveal the electronic relaxation dynamics of a family of five 2-quinolinones with extended conjugated rings. These modifications lead to red-shifted absorbance and emission maxima, relative to unmodified 2-quinolinone. Optical excitation of these molecules with near UV light resulted in transitions with strong π → π* and HOMO → LUMO character. Time-correlated single photon counting measurements yielded fluorescence lifetimes ranging from 849.3 (±0.6) ps to 4.586 (±0.002) ns. Transient absorption spectroscopy revealed relaxation dynamics of the S₁ excited state formed by photoexcitation at 350 nm, along with formation of a long-lived signal assigned as excited state absorption by a triplet excited state. Vibrational relaxation in the S₁ state was also characterized in some compounds. Overlapping signals of S₁ decay and triplet growth in the transient absorption data set could not be fully disentangled. These results demonstrate a highly competitive relaxation scheme following multiple simultaneous pathways, a promising situation for establishing chemical control of electronic relaxation in the 2-quinolinone family.

Synthesis and In Vitro Evaluation of Novel Dopamine Receptor D2 3,4-dihydroquinolin-2(1H)-one Derivatives Related to Aripiprazole

In this pilot study, a series of new 3,4-dihydroquinolin-2(1H)-one derivatives as potential dopamine receptor D₂ (D₂R) modulators were synthesized and evaluated in vitro. The preliminary structure-activity relationship disclosed that compound 5e exhibited the highest D₂R affinity among the newly synthesized compounds. In addition, 5e showed a very low cytotoxic profile and a high probability to cross the blood-brain barrier, which is important considering the observed affinity. However, molecular modelling simulation revealed completely different binding mode of 5e compared to USC-D301, which might be the culprit of the reduced affinity of 5e toward D₂R in comparison with USC-D301.

Pd-catalyzed stereoselective tandem ring-opening amination/cyclization of vinyl γ-lactones: access to caprolactam diversity

A stereoselective amination/cyclization cascade process has been developed that allows for the preparation of a series of unsaturated and substituted caprolactam derivatives in good yields. This conceptually novel protocol takes advantage of the easy access and modular character of vinyl γ-lactones that can be prepared from simple precursors. Activation of the lactone substrate in the presence of a suitable Pd precursor and newly developed phosphoramidite ligand offers a stereocontrolled ring-opening/allylic amination manifold under ambient conditions. The intermediate (E)-configured ε-amino acid can be cyclized using a suitable dehydrating agent in an efficient one-pot, two-step sequence. This overall highly chemo-, stereo- and regio-selective transformation streamlines the production of a wide variety of modifiable and valuable caprolactam building blocks in an operationally attractive way.

NIS-mediated oxidative arene C(sp2)-H amidation toward 3,4-dihydro-2(1H)-quinolinone, phenanthridone, and N-fused spirolactam derivatives

A new radical-mediated intramolecular arene C(sp2)-H amidation of 3-phenylpropanamides or [1,1'-biphenyl]-2-carboxamides was developed to prepare a series of 3,4-dihydro-2(1H)-quinolinone and phenanthridone derivatives in moderate to excellent yields (33-94%). Spirolactams could also be obtained using this protocol.

Carbene-Catalyzed Enantioselective Decarboxylative Annulations to Access Dihydrobenzoxazinones and Quinolones

A direct decarboxylative strategy for the generation of aza-o-quinone methides (aza-o-QMs) by N-heterocyclic carbene (NHC) catalysis has been discovered and explored. This process requires no stoichiometric additives in contrast with current approaches. Aza-o-QMs react with trifluoromethyl ketones through a formal [4+2] manifold to access highly enantioenriched dihydrobenzoxazin-4-one products, which can be converted to dihydroquinolones through an interesting stereoretentive aza-Petasis-Ferrier rearrangement sequence. Complementary dispersion-corrected density functional theory (DFT) studies provided an accurate prediction of the reaction enantioselectivity and lend further insight to the origins of stereocontrol. Additionally, a computed potential energy surface around the major transition structure suggests a concerted asynchronous mechanism for the formal annulation.

A cascade C–H functionalization/cyclization reaction of N-arylpyridin-2-amines with α,β-unsaturated aldehydes for the synthesis of dihydroquinolinone derivatives under rhodium catalysis

A novel rhodium catalyzed cascade C–H functionalization/cyclization reaction of N-arylpyridin-2-amines with α,β-unsaturated aldehydes has been developed.

Medicinal Chemistry of σ1 Receptor Ligands: Pharmacophore Models, Synthesis, Structure Affinity Relationships, and Pharmacological Applications

In the first part of this chapter, we summarize the various pharmacophore models for σ1 receptor ligands. Common to all of them is a basic amine flanked by two hydrophobic regions, representing the pharmacophoric elements. The development of computer-based models like the 3D homology model is described as well as the first crystal structure of the σ1 receptor. The second part focuses on the synthesis and biological properties of different σ1 receptor ligands, identified as 1-9. Monocyclic piperazines 1 and bicyclic piperazines 2 and 3 were developed as cytotoxic compounds, thus the IC50 values of cell growth and survival inhibition studies are given for all derivatives. The mechanism of cell survival inhibition, induction of time-dependent apoptosis, of compound ent-2a is discussed. Experimentally determined σ1 affinity shows good correlation with the results from molecular dynamics simulations based on a 3D homology model. Spirocyclic compounds 4 and 5 represent well-established σ1 receptor ligands. The homologous fluoroalkyl derivatives 4 have favorable pharmacological properties for use as fluorinated PET tracers. The (S)-configured fluoroethyl substituted compound (S)-4b is under investigation as PET tracer for imaging of σ1 receptors in the brain of patients affected by major depression. 1,3-Dioxanes 6c and 6d display a very potent σ1 antagonist profile and the racemic 1,3-dioxane 6c has high anti-allodynic activity at low doses. The arylpropenylamines 7 are very potent σ1 receptor ligands with high σ1/σ2 selectivity. The top compound 7g acts as an agonist as defined by its ability to potentiate neurite outgrowth at low concentrations. Among the morpholinoethoxypyrazoles 8, 8c (known as S1RA) reveals the most promising pharmacokinetic and physicochemical properties. Due to its good safety profile, 8c is currently being investigated in a phase II clinical trial for the treatment of neuropathic pain. The most potent ligand 9e of 3,4-dihydro-2(1H)-quinolones 9 shows promising anti-nociceptive activity in the formalin test.

The importance of triazole scaffold in the development of anticonvulsant agents

Epilepsy is one of the most important neurological disorders with high prevalence worldwide. Many epileptic patients are not completely treated with available drugs and need multiple therapies. Also, many antiepileptic drugs have shown unwanted side effects and drug interactions. Therefore there are continuing interests to find new anticonvulsant drugs. Triazole ring has been found in the structure of many compounds with diverse biological effects. Due to the success of several triazole-containing drugs that entered the pharmaceutical market as CNS-active drugs, this class of heterocyclic compounds has great importance for discovery and development of new anticonvulsant drugs. In this article, we have tried to summarize the latest efforts which have been made in the design and development of triazole-derived anticonvulsant agents.

Piperazine scaffold: A remarkable tool in generation of diverse pharmacological agents

Piperazine is one of the most sought heterocyclics for the development of new drug candidates. This ring can be traced in a number of well established, commercially available drugs. Wide array of pharmacological activities exhibited by piperazine derivatives have made them indispensable anchors for the development of novel therapeutic agents. The review herein highlights the therapeutic significance of piperazine derivatives. Various therapeutically active piperazine derivatives developed by several chemists are reported here.

Sigma receptors [σRs]: biology in normal and diseased states

This review compares the biological and physiological function of Sigma receptors [σRs] and their potential therapeutic roles. Sigma receptors are widespread in the central nervous system and across multiple peripheral tissues. σRs consist of sigma receptor one (σ₁R) and sigma receptor two (σ₂R) and are expressed in numerous regions of the brain. The sigma receptor was originally proposed as a subtype of opioid receptors and was suggested to contribute to the delusions and psychoses induced by benzomorphans such as SKF-10047 and pentazocine. Later studies confirmed that σRs are non-opioid receptors (not an µ opioid receptor) and play a more diverse role in intracellular signaling, apoptosis and metabolic regulation. σ₁Rs are intracellular receptors acting as chaperone proteins that modulate Ca²⁺ signaling through the IP₃ receptor. They dynamically translocate inside cells, hence are transmembrane proteins. The σ₁R receptor, at the mitochondrial-associated endoplasmic reticulum membrane, is responsible for mitochondrial metabolic regulation and promotes mitochondrial energy depletion and apoptosis. Studies have demonstrated that they play a role as a modulator of ion channels (K⁺ channels; N-methyl-d-aspartate receptors [NMDAR]; inositol 1,3,5 triphosphate receptors) and regulate lipid transport and metabolism, neuritogenesis, cellular differentiation and myelination in the brain. σ₁R modulation of Ca²⁺ release, modulation of cardiac myocyte contractility and may have links to G-proteins. It has been proposed that σ₁Rs are intracellular signal transduction amplifiers. This review of the literature examines the mechanism of action of the σRs, their interaction with neurotransmitters, pharmacology, location and adverse effects mediated through them.

Enantioselective annulations for dihydroquinolones by in situ generation of azolium enolates

A convergent, catalytic asymmetric formal [4 + 2] annulation for the synthesis of dihydroquinolones has been developed. Carboxylic acids can be employed as precursors to NHC enolates through an in situ activation strategy. Simultaneous generation of a reactive aza-o-quinone methide under the basic conditions employed for NHC generation leads to a dual activation approach.

Synthesis and biological evaluation of a novel sigma-1 receptor antagonist based on 3,4-dihydro-2(1H)-quinolinone scaffold as a potential analgesic

The synthesis and sigma-1 receptor (σ1R) antagonist activity of a new series of 3,4-dihydro-2(1H)-quinolinone derivatives are reported. The new compounds were evaluated in vitro in sigma-1 and sigma-2 receptor-binding assays in guinea pig brain membranes. The structure-activity relationship led us to the promising derivative 7-(3-(piperidin-1-yl)propoxy)-1-(4-fluorobenzyl)-3,4-dihydro-2(1H)-quinolinone (35). The compounds with highest affinity and greatest selectivity were further profiled, and compound 35 had a high binding constant for sigma-1 receptor (Kiσ1 = 1.22 nM) and high sigma-1/2 selectivity (1066-fold). Thus, compound 35, which proved to be an antagonist of sigma-1 receptor, emerged as the most interesting candidate. In addition, compound 35 exerted dose-dependent anti-nociceptive effects in the formalin test. These characteristics suggested that the potent and selective compound 35 could be a potent candidate for pain treatment.

Recent syntheses of 1,2,3,4-tetrahydroquinolines, 2,3-dihydro-4(1H)-quinolinones and 4(1H)-quinolinones using domino reactions

A review of the recent literature is given focusing on synthetic approaches to 1,2,3,4-tetrahydroquinolines, 2,3-dihydro-4(1H)-quinolinones and 4(1H)-quinolinones using domino reactions. These syntheses involve: (1) reduction or oxidation followed by cyclization; (2) S_NAr-terminated sequences; (3) acid-catalyzed ring closures or rearrangements; (4) high temperature cyclizations and (5) metal-promoted processes as well as several less thoroughly studied reactions. Each domino method is presented with a brief discussion of mechanism, scope, yields, simplicity and potential utility.

Antidepressant potential of nitrogen-containing heterocyclic moieties: An updated review

Depression is currently the fourth leading cause of disease or disability worldwide. Antidepressant is approved for the treatment of major depression (including paediatric depression), obsessive-compulsive disorder (in both adult and paediatric populations), bulimia nervosa, panic disorder and premenstrual dysphoric disorder. Antidepressant is a psychiatric medication used to alleviate mood disorders, such as major depression and dysthymia and anxiety disorders such as social anxiety disorder. Many drugs produce an antidepressant effect, but restrictions on their use have caused controversy and off-label prescription a risk, despite claims of superior efficacy. Our current understanding of its pathogenesis is limited and existing treatments are inadequate, providing relief to only a subset of people suffering from depression. Reviews of literature suggest that heterocyclic moieties and their derivatives has proven success in treating depression.