3-Phenylcoumarins as inhibitors of HIV-1 replication

Coumarin Based Fluorescent Probe for Detecting Heavy Metal Ions

Heavy metals such as Iron, Copper, and Zinc are micro-essential trace metal and involve animportant biological role, but it quickly turns toxic at exceeding the permissible limit, causing gastrointestinal irritation, liver, bone, and kidney damage, as well as disorders including Wilson's, Parkinson's, and Alzheimer's. It is important to detect the metal ions as well as their concentration quickly and affordable cost using organic probes. Among the organic probes,the coumarin fluorescent probe shows a very prominent candidate with heavy metal ions. Therefore, in the present review, we reviewed the very recent literature the identify the heavy metals using modified coumarin fluorescent probes. Readers will get information quickly about the method of preparation of modified coumarin core and their use as fluorescent probes with heavy metals using absorption and emission spectroscopic methods along with the probable mechanistic pathway of detection.

Scoparone chemical modification into semi-synthetic analogues featuring 3-substitution for their anti-inflammatory activity

Natural products (NPs) continue to serve as a structural model for the development of new bioactive molecules and improve the process of identifying novel medicines. The biological effects of coumarins, one of the most researched compounds among NPs, are currently being thoroughly investigated. In the present investigation, we reported the synthesis of nineteen semi-synthetic 3-substituted scoparone analogues, followed by their characterization using analytical methods such as NMR, HPLC, and HRMS. All compounds screened for in vitro and in vivo study for their ability to reduce inflammation. The SAR study worked effectively for this particular scoparone 3-substitution, as compounds 3, 4, 9, 16, 18, and 20 displayed improved in vitro results for TNF-α than the parent molecule. Similarly, compounds 3, and 17 showed a higher percentage of IL-6 inhibition. Compounds 3, 4, and 12 have also been identified by in vivo studies as promising candidates with higher percent inhibition than the parent scoparone molecule. As evident from all in vitro and in vivo studies, compound 3 showed the most potent anti-inflammatory activity among all.

Design, Catalyst-Free Synthesis of New Novel α-Trifluoromethylated Tertiary Alcohols Bearing Coumarins as Potential Antifungal Agents

A new method for the synthesis of α-trifluoromethylated tertiary alcohols bearing coumarins is described. The reaction of 3-(trifluoroacetyl)coumarin and pyrrole provided the target compounds with high yields under catalyst-free, mild conditions. The crystal structure of compound 3fa was investigated by X-ray diffraction analysis. The biological activities, such as in vitro antifungal activity of the α-trifluoromethylated tertiary alcohols against Fusarium graminearum, Fusarium oxysporum, Fusarium moniliforme, Rhizoctonia solani Kuhn, and Phytophthora parasitica var nicotianae, were investigated. The bioassay results indicated that compounds 3ad, 3gd, and 3hd showed broad-spectrum antifungal activity in vitro. Compound 3cd exhibited excellent fungicidal activity against Rhizoctonia solani Kuhn, with an EC₅₀ value of 10.9 μg/mL, which was comparable to that of commercial fungicidal triadimefon (EC₅₀ = 6.1 μg/mL). Furthermore, molecular docking study suggested that 3cd had high binding affinities with 1W9U, like argifin.

Natural source, bioactivity and synthesis of 3-Arylcoumarin derivatives

3-arylcoumarins with different pharmacological properties widely exist in a variety of natural plants. The extensive research on 3-arylcoumarins was attributed to its therapeutic and relatively easy isolation. Therefore, 3-arylcoumarins can be recognised as useful structures for the design of novel compounds with potential pharmacological interest, particularly in the fields of anti-inflammatory, anti-cancer, antioxidant, Monoamine oxidase (MAO) enzyme inhibition, etc. The current review highlights the biological activities, design, and chemical synthetic methods of 3-arylcoumarins derivatives as well as their important natural product sources.

Dual Role of Oxoaldehydes: Divergent Synthesis of 3-Aryl- and 3-Aroylcoumarins

A facile and efficient synthetic approach to various valuable 3-aryl- and 3-aroylcoumarins by the direct arylation and aroylation of coumarins with glyoxals in a metal-free manner is presented. The aryl glyoxal is for the first time recognized to serve as an aryl surrogate in addition to its role as an aroyl transfer reagent via a simple switch in reaction conditions. The approach accommodates a broad substrate scope and high yields of the two types of cross-coupling reactions starting from identical starting materials.

Pharmacological perspectives and molecular mechanisms of coumarin derivatives against virus disease

Infections caused by viruses are one of the foremost causes of morbidity and mortality in the world. Although a number of antiviral drugs are currently used for treatment of various kinds of viral infection diseases, there is still no available therapeutic agent for most of the viruses in clinical practice. Coumarin is a chemical compound which is found naturally in a variety of plants, it can also be synthetically produced possessing diverse biological effects. More recently, reports have highlighted the potential role of coumarin derivatives as antiviral agents. This review outlines the advances in coumarin-based compounds against various viruses including human immunodeficiency virus, hepatitis virus, herpes simplex virus, Chikungunya virus and Enterovirus 71, as well as the structure activity relationship and the possible mechanism of action of the most potent coumarin derivatives.

An Efficient Synthesis of Novel 3-[(Heteroaryl-2-ylimino)-methyl]-4-hydroxy-chromen-2-ones and Analogue of Tetrazole Derivatives and Their Antibacterial Activity

Synthesis of a series of the substituted [(pyridinyl and pyrimidin-2-ylimino)-ethyl]-4-hydroxy-chromen-2-ones and their tetrazole derivates is presented in this study. By catalytic condensation of 4-hydroxy-3-acetylcoumarine 2 and 2-aminopyridines 3(a-d), 3-[(pyridin-2-ylimino)-ethyl]-4-hydroxy-chromen-2-ones 4(a-d) are synthesized in high yield. During the condensation reaction of 2 and 4-amino-2,6-dihydroxypyrimidine 3e, 3-[1-(2,6-Dihydroxy-pyrimidin-4-ylimino)-ethyl]-4-hydroxy-chromen-2-one 4e as condensation products is synthesized. In following series, by cyclization reactions of compounds 4 (a-e) with sodium azide, analogue 3-substituted pyridin-2-yl and pyrimidin-2-yl-5-methyl-2,5-dihydro-1H-tetrazol-5-yl]-4-hydroxy-chromen-2-one 5(a-e) are synthesized the products. Structural characterization of the synthesized products is done on the basis of spectrometric data. Antibacterial activity of the compounds 4(a-e) and 5(a-e) against S. aureus, E. coli and Klebsiella was examined by measuring the inhibition zones around the disks marked with the corresponding products solution. The impact of substitutions in antimicrobial is also explored. Compounds with polar groups have shown significant antibacterial activity against these microorganisms.

3-Phenylcoumarins as a Privileged Scaffold in Medicinal Chemistry: The Landmarks of the Past Decade

3-Phenylcoumarins are a family of heterocyclic molecules that are widely used in both organic and medicinal chemistry. In this overview, research on this scaffold, since 2010, is included and discussed, focusing on aspects related to its natural origin, synthetic procedures and pharmacological applications. This review paper is based on the most relevant literature related to the role of 3-phenylcoumarins in the design of new drug candidates. The references presented in this review have been collected from multiple electronic databases, including SciFinder, Pubmed and Mendeley.

Diversity-Oriented Synthesis: Amino Acetophenones as Building Blocks for the Synthesis of Natural Product Analogs

Diversity-Oriented Synthesis (DOS) represents a strategy to obtain molecule libraries with diverse structural features starting from one common compound in limited steps of synthesis. During the last two decades, DOS has become an unmissable strategy in organic synthesis and is fully integrated in various drug discovery processes. On the other hand, natural products with multiple relevant pharmacological properties have been extensively investigated as scaffolds for ligand-based drug design. In this article, we report the amino dimethoxyacetophenones that can be easily synthesized and scaled up from the commercially available 3,5-dimethoxyaniline as valuable starting blocks for the DOS of natural product analogs. More focus is placed on the synthesis of analogs of flavones, coumarins, azocanes, chalcones, and aurones, which are frequently studied as lead compounds in drug discovery.

Coumarins as Tool Compounds to Aid the Discovery of Selective Function Modulators of Steroid Hormone Binding Proteins

Steroid hormones play an essential role in a wide variety of actions in the body, such as in metabolism, inflammation, initiating and maintaining sexual differentiation and reproduction, immune functions, and stress response. Androgen, aromatase, and sulfatase pathway enzymes and nuclear receptors are responsible for steroid biosynthesis and sensing steroid hormones. Changes in steroid homeostasis are associated with many endocrine diseases. Thus, the discovery and development of novel drug candidates require a detailed understanding of the small molecule structure–activity relationship with enzymes and receptors participating in steroid hormone synthesis, signaling, and metabolism. Here, we show that simple coumarin derivatives can be employed to build cost-efficiently a set of molecules that derive essential features that enable easy discovery of selective and high-affinity molecules to target proteins. In addition, these compounds are also potent tool molecules to study the metabolism of any small molecule.

Design, Synthesis, Molecular Modeling and Anti-HIV Assay of Novel Quinazolinone Incorporated Coumarin Derivatives

BACKGROUND

The emergence of drug-resistant viral strains has created the need for the development of novel anti-HIV agents with a diverse structure that targets key enzymes in the HIV lifecycle.

OBJECTIVE

Considering the pharmacophore of integrase inhibitors, one of the validated targets for anti-HIV therapy, we designed a quinazolinone incorporated coumarin scaffold to affect HIV.

METHODS

Coumarin is a beta enol ester and also a well-known drug scaffold. Designed structures were prepared using a one-pot three-component reaction from 3-amino-4-hydroxycoumarin, isatoic anhydride and benzaldehyde derivatives.

RESULTS

In vitro anti-HIV and cytotoxicity assay indicated that more than half of the compounds had EC50 values lower than 50 µM. Unsubstituted phenyl derivative showed the highest activity and selectivity with an EC50 value of 5 µM and a therapeutic index of 7. Compounds were docked into the integrase active site to investigate the probable mechanism of action. Accordingly, the hydroxyl moiety of coumarin along with the carbonyl of the quinazolinone ring could function as the metal chelating group. Quinazolinone and phenyl groups interact with side chains of IN residues, as well.

CONCLUSION

Here, a novel anti-HIV scaffold is represented for further modification and in-vivo studies.

Coumarin-based derivatives with potential anti-HIV activity

Acquired immunodeficiency syndrome (AIDS), as a result of human immunodeficiency virus (HIV) infection which leads to severe suppression of immune functions, is an enormous world-wide health threat. The anti-HIV agents are critical for the HIV/AIDS therapy, but the generation of viral mutants and the severe side effects of the anti-HIV agents pose serious hurdles in the treatment of HIV infection, and creat an urgent need to develop novel anti-HIV agents. The plant-derived compounds possess structural and mechanistic diversity, and among them, coumarin-based derivatives have the potential to inhibit different stages in the HIV replication cycle, inclusive of virus-host cell attachment, cell membrane fusion, integration, assembly besides the conventional target like inhibition of the reverse transcriptase, protease, and integrase. Moreover, (+)-calanolide A, a coumarin-based natural product, is a potential anti-HIV agent. Thus, coumarin-based derivatives are useful scaffolds for the development of anti-HIV agents. This review article describes the recent progress in the discovery, structural modification, and structure-activity relationship studies of potent anti-HIV coumarin-based derivatives including natural coumarin compounds, synthetic hybrids, dimers, and other synthetic derivatives covering articles published between 2000 and 2020.

Recent Advances in Functional Polymers Containing Coumarin Chromophores

Natural and synthetic coumarin derivatives have gained increased attention in the design of functional polymers and polymer networks due to their unique optical, biological, and photochemical properties. This review provides a comprehensive overview over recent developments in macromolecular architecture and mainly covers examples from the literature published from 2004 to 2020. Along with a discussion on coumarin and its photochemical properties, we focus on polymers containing coumarin as a nonreactive moiety as well as polymer systems exploiting the dimerization and/or reversible nature of the [2πs + 2πs] cycloaddition reaction. Coumarin moieties undergo a reversible [2πs + 2πs] cycloaddition reaction upon irradiation with specific wavelengths in the UV region, which is applied to impart intrinsic healability, shape-memory, and reversible properties into polymers. In addition, coumarin chromophores are able to dimerize under the exposure to direct sunlight, which is a promising route for the synthesis and cross-linking of polymer systems under "green" and environment-friendly conditions. Along with the chemistry and design of coumarin functional polymers, we highlight various future application fields of coumarin containing polymers involving tissue engineering, drug delivery systems, soft robotics, or 4D printing applications.

Coumarin derivative 7-isopentenyloxycoumarin induces in vivo antitumor activity by inhibit angiogenesis via CCL2 chemokine decrease

Cancer is one of the most urgent problems in medicine. In recent years, cancer is the second leading cause of death globally. In search for more effective and less toxic treatment against cancer, natural products are used as prototypes in the synthesis of new anticancer drugs. The aim of this study was to investigate the in vivo toxicity and the mechanism of antitumor action of 7-isopentenyloxycoumarin (UMB-07), a coumarin derivative with antitumor activity. The toxicity was evaluated in vitro (hemolysis assay), and in vivo (micronucleus and acute toxicity assays). Ehrlich ascites carcinoma model was used to evaluate in vivo antitumor activity of UMB-07 (12.5, 25, or 50 mg/kg, intraperitoneally, i.p.), after 9 days of treatment, as well as toxicity. UMB-07 (2000 μg/mL) induced only 0.8% of hemolysis in peripheral blood erythrocytes of mice. On acute toxicity assay, LD₅₀ (50% lethal dose) was estimated at around 1000 mg/kg (i.p.), and no micronucleated erythrocytes were recorded after UMB-07 (300 mg/kg, i.p.) treatment. UMB-07 (25 and 50 mg/kg) reduced tumor volume and total viable cancer cells. In the mechanism action investigation, no changes were observed on the cell cycle analysis; however, UMB-07 reduced peritumoral microvessels density and CCL2 chemokine levels. In addition, UMB-07 showed weak toxicity on biochemical, hematological, and histological parameters after 9 days of antitumor treatment. The current findings suggest that UMB-07 has low toxicity and exerts antitumor effect by inhibit angiogenesis via CCL2 chemokine decrease.

Recent Advances in the Synthesis of Coumarin Derivatives from Different Starting Materials

The study of coumarin dates back to 1820 when coumarin was first extracted from tonka bean by Vogel. Compounds containing coumarin backbone are a very important group of compounds due to their usage in pharmacy and medicine. Properties and biological activities of coumarin derivatives have a significant role in the development of new drugs. Therefore, many different methods and techniques are developed in order to synthesize coumarin derivatives. Coumarin derivatives could be obtained from different starting materials with various methods but with big differences in yield. This review summarized various methods, techniques and reaction conditions for synthesis of coumarins from different compounds such as aldehydes, phenols, ketones and carboxylic acids.

Chlorophyll-catalyzed photochemical regioselective coumarin C–H arylation with diazonium salts

A metal-free, direct C–H arylation of coumarins with aryl diazonium salts at room temperature using chlorophyll as a green photosensitizer is devised.

Microwave-assisted synthesis, biological evaluation and molecular docking studies of new coumarin-based 1,2,3-triazoles

Coumarin-based 1,4-disubstituted 1,2,3-triazole derivatives were synthesized using a highly efficient, eco-friendly protocol via a copper(i)-catalyzed click reaction between various substituted arylazides and terminal alkynes.

Green Synthesis of Spiropyranone 3-Aryl-4-Methylcoumarin Derivatives using Carbonyldiimidazole

A series of spiropyranone 3-aryl-4-methylcoumarin derivatives have been synthesized from monospiro-2-hydroxy acetophenone in a novel and efficient green method using imidazolyl intermediates and inorganic base. Imidazolyl intermediates were in turn generated by grinding the respective phenylacetic acid along with carbonyldiimidazole (CDI). Similarly, monospiro-2-hydroxy acetophenone derivatives were prepared selectively by avoiding formation of bis derivatives following literature procedure. The titled compounds were purified by preparative TLC technique and were characterized by IR, 1H NMR, 13C NMR as well as mass spectral methods

Direct C-3 alkylation of coumarins via decarboxylative coupling with carboxylic acids

A metal-free direct alkylation of coumarins using carboxylic acids in aqueous media with a broad substrate scope is devised.

Blocking oestradiol synthesis pathways with potent and selective coumarin derivatives

A comprehensive set of 3-phenylcoumarin analogues with polar substituents was synthesised for blocking oestradiol synthesis by 17-β-hydroxysteroid dehydrogenase 1 (HSD1) in the latter part of the sulphatase pathway. Five analogues produced ≥62% HSD1 inhibition at 5 µM and, furthermore, three of them produced ≥68% inhibition at 1 µM. A docking-based structure-activity relationship analysis was done to determine the molecular basis of the inhibition and the cross-reactivity of the analogues was tested against oestrogen receptor, aromatase, cytochrome P450 1A2, and monoamine oxidases. Most of the analogues are only modestly active with 17-β-hydroxysteroid dehydrogenase 2 – a requirement for lowering effective oestradiol levels in vivo. Moreover, the analysis led to the synthesis and discovery of 3-imidazolecoumarin as a potent aromatase inhibitor. In short, coumarin core can be tailored with specific ring and polar moiety substitutions to block either the sulphatase pathway or the aromatase pathway for treating breast cancer and endometriosis.

Combined in Vitro and in Silico Studies for the Anticholinesterase Activity and Pharmacokinetics of Coumarinyl Thiazoles and Oxadiazoles

In a continuation of our previous work for the exploration of novel enzyme inhibitors, two new coumarin-thiazole 6(a–o) and coumarin-oxadiazole 11(a–h) hybrids have been designed and synthesized. All the compounds were characterized by ¹H- and ¹³C-NMR spectroscopy and elemental analysis. New hybrid analogs were evaluated against acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) in order to know their potential for the prevention of Alzheimer's disease (AD). In coumarinyl thiazole series, compound 6b was found as the most active member against AChE having IC₅₀ value of 0.87 ± 0.09 μM, while the compound 6j revealed the same efficacy against BuChE with an IC₅₀ value of 11.01 ± 3.37 μM. In case of coumarinyl oxadiazole series, 11a was turned out to be the lead candidate against AChE with an IC₅₀ value of 6.07 ± 0.23 μM, whereas compound 11e was found significantly active against BuChE with an IC₅₀ value of 0.15 ± 0.09 μM. To realize the binding interaction of these compounds with AChE and BuChE, the molecular docking studies were performed. Compounds from coumarinyl thiazole series with potent AChE activity (6b, 6h, 6i, and 6k) were found to interact with AChE in the active site with MOE score of −10.19, −9.97, −9.68, and −11.03 Kcal.mol⁻¹, respectively. The major interactions include hydrogen bonding, π-π stacking with aromatic residues, and interaction through water bridging. The docking studies of coumarinyl oxadiazole derivatives 11(a–h) suggested that the compounds with high anti-butyrylcholinesterase activity (11e, 11a, and 11b) provided MOE score of −9.9, −7.4, and −8.2 Kcal.mol⁻¹, respectively, with the active site of BuChE building π-π stacking with Trp82 and water bridged interaction.

The 3-phenylcoumarin derivative 6,7-dihydroxy-3-[3',4'-methylenedioxyphenyl]-coumarin downmodulates the FcγR- and CR-mediated oxidative metabolism and elastase release in human neutrophils: Possible mechanisms underlying inhibition of the formation and release of neutrophil extracellular traps

In this study, we report the ability of a set of eight 3-phenylcoumarin derivatives bearing 6,7- or 5,7-dihydroxyl groups, free or acetylated, bound to the benzopyrone moiety, to modulate the effector functions of human neutrophils. In general, (i) 6,7-disubstituted compounds (5, 6, 19, 20) downmodulated the Fcγ receptor-mediated neutrophil oxidative metabolism more strongly than 5,7-disubstituted compounds (21, 22, 23, 24), and (ii) hydroxylated compounds (5, 19, 21, 23) downmodulated this neutrophil function more effectively than their acetylated counterparts (6, 20, 22, 24, respectively). Compounds 5 (6,7-dihydroxy-3-[3',4'-methylenedioxyphenyl]-coumarin) and 19 (6,7-dihydroxy-3-[3',4'-dihydroxyphenyl]-coumarin) effectively downmodulated the neutrophil oxidative metabolism elicited via Fcγ and/or complement receptors. Compound 5 also downmodulated the immune complex-stimulated phagocytosis, degranulation of elastase, and production and release of neutrophil extracellular traps, as well as the human neutrophil chemotaxis towards n-formyl-methionyl-leucyl-phenylalanine, without altering the expression level of formyl peptide receptor type 1. Both compounds 5 and 19 did not impair the neutrophil capacity to recognize and kill Candida albicans. Docking calculations revealed that compounds 5 and 19 directly interacted with three catalytic residues - Gln-91, His-95, and Arg-239 - inside the myeloperoxidase active site. Together, these findings indicate that (i) inhibition of reactive oxygen species generation and degranulation of elastase are closely associated with downmodulation of release of neutrophil extracellular traps; and (ii) compound 5 can be a prototype for the development of novel immunomodulating drugs to treat immune complex-mediated inflammatory diseases.

Peroxy mediated Csp2–Csp3 dehydrogenative coupling: regioselective functionalization of coumarins and coumarin-3-carboxylic acids

Regioselective functionalization of coumarins/coumarin carboxylic acids at C-3 via activation of Csp³–H bonds of ethers under metal-free conditions is developed.

Design, Synthesis, Molecular Modeling, In Silico ADME Studies and Anti-HIV-1 Assay of New Diazocoumarin Derivatives

Some new diazo incorporated coumarin compounds were designed and synthesized to evaluate their anti-HIV activity. Overall, compounds were active against HIV at 100 μM. Additionally, no cytotoxic effect was observed at this concentration. The compound with 4-chlorobenzyl group indicated the best anti-HIV activity (52%). Docking studies using the later crystallographic data available for PFV integrase showed similar binding modes to HIV-1 integrase inhibitors. On the basis of these data, nitrogen atoms of 1,3,4-oxadiazole ring have been involved in the Mg²⁺ chelation and 4-chlorobenzyl group occupies the same position as 4-flourobenzyl group of raltegravir in the active site. In addition, in silico ADME assay demonstrated favorable physicochemical properties for the new designed compounds. Thus, synthesized structures could be introduced as a novel template for designing safe anti-HIV compounds with integrase inhibitory potential.

Therapeutic potential of coumarins as antiviral agents

Coumarins have received a considerable attention in the last three decades as a lead structures for the discovery of orally bioavailable non-peptidic antiviral agents. A lot of structurally diverse coumarins analogues were found to display remarkable array of affinity with the different molecular targets for antiviral agents and slight modifications around the central motif result in pronounced changes in its antiviral spectrum. This manuscript thoroughly reviews the design, discovery and structure-activity relationship studies of the coumarin analogues as antiviral agents focusing mainly on lead optimization and its development into clinical candidates.

Regioselective C-3 arylation of coumarins with arylhydrazines via radical oxidation by potassium permanganate

An efficient protocol for oxidative C-3 arylation of coumarins with arylhydrazine has been developed using potassium permanganate as an oxidant. The arylated coumarins with different electronic properties were obtained in moderate to good yields. The developed protocol for direct C-3 arylation of coumarins could be extended to quinolinones.

N-Benzylpiperidine Derivatives as α7 Nicotinic Receptor Antagonists

A series of multitarget directed propargylamines, as well as other differently susbstituted piperidines have been screened as potential modulators of neuronal nicotinic acetylcholine receptors (nAChRs). Most of them showed antagonist actions on α7 nAChRs. Especially, compounds 13, 26, and 38 displayed submicromolar IC50 values on homomeric α7 nAChRs, whereas they were less effective on heteromeric α3β4 and α4β2 nAChRs (up to 20-fold higher IC50 values in the case of 13). Antagonism was concentration dependent and noncompetitive, suggesting that these compounds behave as negative allosteric modulators of nAChRs. Upon the study of a series of less complex derivatives, the N-benzylpiperidine motif, common to these compounds, was found to be the main pharmacophoric group. Thus, 2-(1-benzylpiperidin-4-yl)-ethylamine (48) showed an inhibitory potency comparable to the one of the previous compounds and also a clear preference for α7 nAChRs. In a neuroblastoma cell line, representative compounds 13 and 48 also inhibited, in a concentration-dependent manner, cytosolic Ca(2+) signals mediated by nAChRs. Finally, compounds 38 and 13 inhibited 5-HT3A serotonin receptors whereas they had no effect on α1 glycine receptors. Given the multifactorial nature of many pathologies in which nAChRs are involved, these piperidine antagonists could have a therapeutic potential in cases where cholinergic activity has to be negatively modulated.

Ultrasound-Assisted Solvent-Free Parallel Synthesis of 3-Arylcoumarins Using N-Acylbenzotriazoles

An ultrasound-assisted one-pot acylation/cyclization reaction between N-acylbenzotriazoles and 2-hydroxybenzaldehydes has been developed for the synthesis of substituted 3-arylcoumarins. Using ultrasound not only allows rapid and clean conversion but also simplifies experimental setup and parallel workup leading to rapid generation of 3-arylcoumarin libraries under mild, solvent-free, and chromatography-free conditions.

Down-regulatory mechanism of mammea E/BB from Mammea siamensis seed extract on Wilms' Tumor 1 expression in K562 cells

Background

Wilms’ tumor 1 (WT1) is a biological marker for predicting leukemia progression. In this study, mammea E/BB, an active compound from Saraphi (Mammea siamensis) seed extract was examined for its effect on down-regulatory mechanism of WT1 gene expression, WT1 protein and mRNA stability, and cell proliferation in K562 cell line.

Methods

M. siamensis seeds were obtained from the region of Chiang Mai (North of Thailand). Mammea E/BB was extracted from seeds of M. siamensis. WT1 protein expression and stability were evaluated by Western blot analysis. WT1 mRNA stability was assessed by qRT-PCR. WT1-DNA binding and WT1 promoter activity were assayed by ChIP assay and luciferase-reporter assay, respectively. Cell cycle arrest was studied by flow cytometry.

Results

Treatment with mammea E/BB led to down-regulation of WT1 expression. The suppression of WT1 expression did not involve protein and mRNA degradation. Rather, WT1 protein was down-regulated through disruption of transcriptional auto-regulation of the WT1 gene. Mammea E/BB inhibited WT1-DNA binding at the WT1 promoter and decreased luciferase activity. It also disrupted c-Fos/AP-1 binding to the WT1 promoter via ERK1/2 signaling pathway and induced S phase cell cycle arrest in K562 cells.

Conclusion

Mammea E/BB had pleotropic effects on kinase signaling pathways, resulting in inhibition of leukemia cell proliferation.

Electronic supplementary material

The online version of this article (doi:10.1186/s12906-016-1107-z) contains supplementary material, which is available to authorized users.

Novel 7-oxy-3-(3′,4′,5′-trimethoxyphenyl)coumarin substituted zinc(II) phthalocyanines: Synthesis, characterization, photophysical and photochemical properties

The novel zinc(II) phthalocyanine complexes bearing tetra or octa-[7-oxy-3-(3′,4′,5′-trimethoxyphenyl)coumarin] moieties were synthesized for the first time in this study. These phthalocyanines were characterized by different spectroscopic methods such as FT-IR, 1H NMR, electronic absorption spectra, MALDI-TOF mass and elemental analyses as well. The photochemical properties such as singlet oxygen generation, photostability and photophysical properties such as fluorescence quantum yields and lifetimes were investigated in [Formula: see text],[Formula: see text]-dimethylformamide (DMF) solutions. The effect of the structure (the position and number of the coumarin groups on phthalocyanine framework) of novel phthalocyanines on these properties was also determined in this study.

Regioselective α-arylation of coumarins and 2-pyridones with phenylhydrazines under transition-metal-free conditions

A transition-metal-free regioselective α-arylation of coumarins and 2-pyridones has been accomplished by the reaction of phenylhydrazines with coumarins or 2-pyridones.

KMnO4/AcOH-mediated C3-selective direct arylation of coumarins with arylboronic acids

An efficient protocol for KMnO₄/AcOH-mediated C3-direct radical arylation of coumarins with arylboronic acids to afford 3-arylcoumarin derivatives is described.

Synthesis, cholinesterase inhibition and molecular modelling studies of coumarin linked thiourea derivatives

Alzheimer's disease is among the most widespread neurodegenerative disorder. Cholinesterases (ChEs) play an indispensable role in the control of cholinergic transmission and thus the acetylcholine level in the brain is enhanced by inhibition of ChEs. Coumarin linked thiourea derivatives were designed, synthesized and evaluated biologically in order to determine their inhibitory activity against acetylcholinesterases (AChE) and butyrylcholinesterases (BChE). The synthesized derivatives of coumarin linked thiourea compounds showed potential inhibitory activity against AChE and BChE. Among all the synthesized compounds, 1-(2-Oxo-2H-chromene-3-carbonyl)-3-(3-chlorophenyl)thiourea (2e) was the most potent inhibitor against AChE with an IC50 value of 0.04±0.01μM, while 1-(2-Oxo-2H-chromene-3-carbonyl)-3-(2-methoxyphenyl)thiourea (2b) showed the most potent inhibitory activity with an IC50 value of 0.06±0.02μM against BChE. Molecular docking simulations were performed using the homology models of both cholinesterases in order to explore the probable binding modes of inhibitors. Results showed that the novel synthesized coumarin linked thiourea derivatives are potential candidates to develop for potent and efficacious acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitors.

Computational and spectral studies of 6-phenylazo-3-(p-tolyl)-2H-chromen-2-one

6-Phenylazo-3-(p-tolyl)-2H-chromen-2-one 4 was prepared and characterized by IR, (1)H, and (13)C NMR spectral studies. The optimized structure of the chromen-2-one 4 was investigated by the Gaussian 03 B3LYP density functional method calculations at 6-31G(d,p) basis set. The gauge-independent atomic orbital (GIAO) (13)C and (1)H chemical shift calculations for the synthesized chromen-2-one in CDCl3 were also made by the same method. The computed IR frequencies of the chromen-2-one and the corresponding vibrational assignments were analyzed by means of potential energy distribution (PED%) calculation using vibrational energy distribution analysis (VEDA) program. The first order hyperpolarizability (βtot), polarizability (α) and dipole moment (μ) were calculated using 6-311G(d,p) basis set and the nonlinear optical (NLO) properties are also addressed theoretically. Stability of the chromen-2-one 4 molecule has been analyzed by calculating the intramolecular charge transfer using natural bond order (NBO) analysis. The molecular electrostatic potentials, HOMO-LUMO energy gap and geometrical parameters were also computed. Topological properties of the electronic charge density in chromen-2-one 4 were analyzed employing the Bader's Atoms in Molecule (AIM) theory which indicated the presence of intramolecular hydrogen bond in the molecule.