Journal articles: 'Coumarin ring'

1

Prahadeesh, N., Maheswaran Sithambaresan, and Umaramani Mathiventhan. "A Study on Hydrogen Peroxide Scavenging Activity and Ferric Reducing Ability of Simple Coumarins." Emerging Science Journal 2, no. 6 (December 13, 2018): 417. http://dx.doi.org/10.28991/esj-2018-01161.

Full text

Abstract:

Coumarin compounds are δ-lactones where α-pyrone ring is fused with benzene ring. Coumarins are widely distributed in the plant kingdom as well as they are very important in synthetic organic chemistry. Coumarins have great interest because of their abundance in nature and diverse pharmacological activities including antibacterial, antiviral, antipyretic, and anticoagulant, antioxidant, anti-inflammatory and anticancer. This study focused on synthesizing different simple Coumarins and studying their antioxidant activity. Four simple Coumarins (Coumarin (C1), 4-hydroxy coumarin (C2), 7-hydroxy coumarin (C3) and 7-hydoxy-4-methyl coumarin (C4)) were synthesized by using standard methods and were characterized by using UV, IR, 1H and 13C NMR spectra. Antioxidant activity of the simple Coumarins was studied by using standard FRAP assay and Hydrogen peroxide assay and expressed as FRAP value (mmol Fe2+/g) and IC50 value (mg/dm-3) respectively. Ascorbic acid was used as standard. All synthesized simple Coumarins showed both antioxidant activities. Hydroxyl Coumarins (C2, C3 and C4) showed higher activities in both cases than C1. Among the hydroxyl Coumarins C3 showed highest hydrogen peroxide scavenging activity and Ferric reducing capacity too. Antioxidant power of the tested simple Coumarins in decreasing order was C3, C2, C4 and C1 in both cases. But the hydrogen peroxide scavenging activity and Ferric reducing capacity of the all synthesized simple Coumarins were lower when compared to standard ascorbic acid.

APA, Harvard, Vancouver, ISO, and other styles

2

Mohan, Resmi, M. Vidhyalakshmi, and Venkatasubramanian Sivakumar. "Microwave Assisted Rapid Extraction and Characterization of Coumarin from Fig Plant (Ficus carica)." Asian Journal of Science and Applied Technology 8, no. 1 (May 5, 2019): 1–4. http://dx.doi.org/10.51983/ajsat-2019.8.1.1043.

Full text

Abstract:

Coumarins are fragrant natural bioactive organic compound find application as aroma, flavor and wide medicinal use. Fig plant (Ficus Carica) is a very good source of Coumarins. Coumarins are a member of the benzopyrone family and it has a benzene ring joined to a pyrone ring. There is a need for effective extraction and purification of Coumarins from plant materials. Different methods of extraction of Courmarin from Ficus Carica has been studied in this paper, among them, microwave extraction (180 W power) provided rapid extraction with 10 minutes time with extract yield of 0.67 g as compared to that of 1 hour of water bath extraction at 60C. Coumarin was isolated from the crude extract using NaOH and petroleum ether and their presence was characterized confirmed using UV spectroscopy, IR spectroscopy, TLC and fluorescence test. The antibacterial activity of coumarin was also evaluated using disc diffusion method and Minimum Inhibition Count (MIC). The present study analyzes and provides method of microwave assisted rapid extraction of Coumarin from Fig plant (Ficus Carica) and its characterization, which could be widely used as generic method from natural materials for different applications.

APA, Harvard, Vancouver, ISO, and other styles

3

Yoon, Jeong A., and Young Taek Han. "Efficient Synthesis of Pyrido[3,2-c]coumarins via Silver Nitrate Catalyzed Cycloisomerization and Application to the First Synthesis of Polyneomarline C." Synthesis 51, no. 24 (September 30, 2019): 4611–18. http://dx.doi.org/10.1055/s-0037-1610730.

Full text

Abstract:

Herein, we report an efficient method for the synthesis of the pyrido[3,2-c]coumarin scaffold, one of the privileged heterocycle-fused coumarin scaffolds, via a AgNO3-catalyzed cycloisomerization of 4-(propynylamino)coumarins obtained from diverse 4-hydroxycoumarins. This concise method affords pyrido[3,2-c]coumarin analogues bearing diverse substituents on the benzene or pyridine ring in moderate to good yields. Moreover, this methodology was extended to the facile synthesis of polyneomarline C, a natural pyrido[3,2-c]coumarin derivative isolated from the Chinese herbal medicine Polyalthia nemoralis A. DC., in three steps and in 26% overall yield from the known 4-hydroxycoumarin.

APA, Harvard, Vancouver, ISO, and other styles

4

Kumari, Sumita, Amit Sharma, and Sonia Yadav. "Pharmacological Potential of Coumarin-Based Derivatives: (A Comprehensive Brief Review)." Oriental Journal Of Chemistry 39, no. 3 (June 30, 2023): 568–76. http://dx.doi.org/10.13005/ojc/390304.

Full text

Abstract:

By combining of benzene nucleus and pyrone ring a class of heterocyclic compounds known as benzopyrone is generated. As a basic parent scaffold 1,2- benzopyrone ring system contains by coumarins. These compounds can be divided into two groups: 1. Benzo-α-pyrone 2. Benzo-γ-pyrone. Data on different coumarin derivatives are gathered in this review article as these compounds have a wide spectrum of pharmacological actions and can be further modified to make more potent and effective medications. Derivatives of coumarin play a significant role in industries and sectors of medicine. This can be linked to their variety of chemical characteristics and multiple biological activities. Coumarin based derivatives has a phenolic hydroxyl group which is generated as one of the most derivative functional groups. The focus of this systematic and comprehensive review on synthetic pathway of coumarin affiliates and their biological activities or potential. According to authors this review could help to medicinal chemists to choose appropriate functional group for development of novel therapeutic drugs.

APA, Harvard, Vancouver, ISO, and other styles

5

Medyouni, Rawdha, Olfa Naouali, Naceur HAMDI, and Lassaad Baklouti. "Coumarin phthalonitriles: Synthesis and cation binding properties." JOURNAL OF ADVANCES IN CHEMISTRY 11, no. 4 (March 9, 2015): 3512–18. http://dx.doi.org/10.24297/jac.v11i4.6695.

Full text

Abstract:

Coumarin possess a number of biological activities like anticoagulant, antimicrobial, anti-inflammatory, analgesic,antioxidant, anticancer, antiviral, antimalarial etc. Coumarin belongs to a group as benzopyrones, which consists of a benzene ring joined to a pyrone nucleus. In this work, new coumarin phtalonitriles derivatives were synthesized and characterized via spectroscopic techniques IR, 1H NMR, 13C NMR, mass spectra and elemental analysis.The synthesis of coumarin phtalonitriles resulting from a nucleophilic aromatic substitution reaction between 4-nitrophtalonitrile and coumarins derivatives. The complexing properties of the coumarin derivatives toward alkali metal, alkaline earth metal, some transition metals and some heavy metal cations have been investigated in acetonitrile by means of UV spectrophotometry absorption and conductivity methods. Thus, the stoichiometry of the complexes formed and their stability constants were determined

APA, Harvard, Vancouver, ISO, and other styles

6

Cheke, Rameshwar S., Harun M. Patel, Vaishali M. Patil, Iqrar Ahmad Ansari, Jaya P. Ambhore, Sachin D. Shinde, Adel Kadri, et al. "Molecular Insights into Coumarin Analogues as Antimicrobial Agents: Recent Developments in Drug Discovery." Antibiotics 11, no. 5 (April 24, 2022): 566. http://dx.doi.org/10.3390/antibiotics11050566.

Full text

Abstract:

A major global health risk has been witnessed with the development of drug-resistant bacteria and multidrug-resistant pathogens linked to significant mortality. Coumarins are heterocyclic compounds belonging to the benzophenone class enriched in different plants. Coumarins and their derivatives have a wide range of biological activity, including antibacterial, anticoagulant, antioxidant, anti-inflammatory, antiviral, antitumour, and enzyme inhibitory effects. In the past few years, attempts have been reported towards the optimization, synthesis, and evaluation of novel coumarin analogues as antimicrobial agents. Several coumarin-based antibiotic hybrids have been developed, and the majority of them were reported to exhibit potential antibacterial effects. In the present work, studies reported from 2016 to 2020 about antimicrobial coumarin analogues are the focus. The diverse biological spectrum of coumarins can be attributed to their free radical scavenging abilities. In addition to various synthetic strategies developed, some of the structural features include a heterocyclic ring with electron-withdrawing/donating groups conjugated with the coumarin nucleus. The suggested structure−activity relationship (SAR) can provide insight into how coumarin hybrids can be rationally improved against multidrug-resistant bacteria. The present work demonstrates molecular insights for coumarin derivatives having antimicrobial properties from the recent past. The detailed SAR outcomes will benefit towards leading optimization during the discovery and development of novel antimicrobial therapeutics.

APA, Harvard, Vancouver, ISO, and other styles

7

Thakur, Abhinay, Rohit Sharma, Vivek Sheel Jaswal, Eugenie Nepovimova, Ashun Chaudhary, and Kamil Kuca. "Psoralen: A Biologically Important Coumarin with Emerging Applications." Mini-Reviews in Medicinal Chemistry 20, no. 18 (December 7, 2020): 1838–45. http://dx.doi.org/10.2174/1389557520666200429101053.

Full text

Abstract:

Coumarin belongs to a class of lactones that are fundamentally comprised of a benzene ring fused to an α-pyrone ring; these lactones are known as benzopyrones. Similarly, coumarin has a conjugated electron-rich framework and good charge-transport properties. Plants produce coumarin as a chemical response to protect themselves from predation. Coumarins are used in different products, such as cosmetics, additives, perfumes, aroma enhancers in various tobaccos and some alcoholic drinks, and they play a relevant role in natural products and in organic and medicinal chemistry. In addition, as candidate drugs, many coumarin compounds have strong pharmacological activity, low toxicity, high bioavailability and better curative effects and have been used to treat various types of diseases. Various endeavors were made to create coumarin-based anticoagulant, antimicrobial, antioxidant, anticancer, antidiabetic, antineurodegenerative, analgesic and anti-inflammatory agents. A class of chemical compounds called furocoumarins has phototoxic properties and is naturally synthesized via the fusion of coumarin to a furan ring in different plant species. Psoralens belong to the furocoumarin class and occur naturally in various plants, e.g., lemons, limes, and parsnips. Angelicin is an isomer of psoralens, and most furocoumarins, e.g., xanthotoxin, bergapten, and nodekenetin, are derivatives of psoralens or angelicin. The present work demonstrated that psoralen molecules exhibit anti-tumoral activity against breast cancer and influence different intracellular signals to maintain the high survival of breast cancer cells. Psoralens perform different functions, e.g., antagonize metabolic pathways, protease enzymes, and cell cycle progression and even interfere in the crosslinking between receptors and growth factor mitogenic signaling.

APA, Harvard, Vancouver, ISO, and other styles

8

Jalhan, Sunny. "Review Article: Various Biological Activities of Coumarin and Oxadiazole Derivatives." Asian Journal of Pharmaceutical and Clinical Research 10, no. 7 (July 1, 2017): 38. http://dx.doi.org/10.22159/ajpcr.2017.v10i7.18461.

Full text

Abstract:

In this review article data is collected regarding the various derivatives of coumarin and oxadiazole as both these have wide range of biological activities and they can be further modified to synthesize more effective and potent drugs. Coumarin class of organic compounds consists of 1,2-benzopyrone ring system as a basic parent scaffold. These benzopyrones are subdivided into alpha-benzopyrones and gamma benzopyrones; with coumarin class of compounds belonging to alpha-benzopyrones. Since the last few years, coumarins were synthesized in many of their derivative forms. Their pharmacological, therapeutic and biochemical properties depend upon their pattern of substitution. Coumarins exhibit a wide range of pharmacological activities, which includes anti-diabetic, anti-viral, anti-microbial, anticancer, anti-oxidant, anti-parasitic, anti-helminthic, anti-proliferative, anti-convulsant, anti-inflammatory and antihypertensive activities. 1,3,4-Oxadiazole is a heterocyclic compound containing an oxygen atom and two nitrogen atoms in a five-membered ring. It is derived from furan by substitution of two methylene groups (=CH) with two pyridine type nitrogens (-N=). There are three known isomers: 1,2,4-oxadiazole, 1,2,3-oxadiazole and 1,2,5- oxadiazole. Oxadiazole moiety shows antimicrobial, anticancer and anti-inflammatory activity and suitably substituted 1,3,4-oxadiazole having biological activities like antimicrobial, anticancer and other biological activities.

APA, Harvard, Vancouver, ISO, and other styles

9

Sanaryh Mohammed Al-awad, Leaqaa Abdalredha raheem, and Ausama Ayob Jaccob. "Synthesis and Pharmacological Evaluation of Novel Coumarin Derivatives." International Journal of Research in Pharmaceutical Sciences 11, no. 1 (January 27, 2020): 865–74. http://dx.doi.org/10.26452/ijrps.v11i1.1908.

Full text

Abstract:

The current work focuses on new architecture, synthesis of coumarin-oxadiazole hybrid derivative products as both these (coumarin ring and oxadiazole) have a wide variety of biological behavior, Compounds containing the nucleus of coumarin (2H-1-benzopyran-2-one) are an interesting class of hetero cycles which hold an important role in the field of natural ingredients and synthetic organic chemistry. It has been exciting medicinal chemists to study native coumarins or synthetic analogs for their application for decades. And they can be further modified to synthesize more effective and potent drugs. Compounds have been characterized by spectrophotometry of physicochemical properties and their structures verified by infrared spectroscopy (FTIR) and nuclear magnetic resonance (1H-NMR) Such new derivatives of coumarinyl-oxadiazole was qualified to estimate the lethal dose, anticancer, anticoagulant and antioxidant activity. Their pharmacological properties depend on their pattern of substitution, compound S4F proved significant anticoagulant activity in concentration (50, 100, 200 mg/ml) similar for heparin, and monitor the coagulation effect on plasma, while compound S4CO give significant anticancer activity against MCF-7 a breast cancer cell. Specific compounds have strong antioxidants with the effective action of radical scavengers; the S4Cl compound with IC50 1.49 is the most potent antioxidant activity note. Basically, all the formulations tested reported satisfactory behavior. The review shows that varieties of coumarin derivatives have synthesized and shown anti-cancer, antioxidant and anti-coagulant potentials. These derivatives synthesis and its biological assay can be further modified in the future to improve the anti-cancer, anti-oxidant and anticoagulant potentials of the versatile coumarin nucleus.

APA, Harvard, Vancouver, ISO, and other styles

10

Zeydi, Masoud Mohammadi, Seyed Jafar Kalantarian, and Zahra Kazeminejad. "Overview on developed synthesis procedures of coumarin heterocycles." Journal of the Iranian Chemical Society 17, no. 12 (June 27, 2020): 3031–94. http://dx.doi.org/10.1007/s13738-020-01984-1.

Full text

Abstract:

Abstract Considering highly valuable biological and pharmaceutical properties of coumarins, the synthesis of these heterocycles has been considered for many organic and pharmaceutical chemists. This review includes the recent research in synthesis methods of coumarin systems, investigating their biological properties and describing the literature reports for the period of 2016 to the middle of 2020. In this review, we have classified the contents based on co-groups of coumarin ring. These reported methods are carried out in the classical and non-classical conditions particularly under green condition such as using green solvent, catalyst and other procedures.

APA, Harvard, Vancouver, ISO, and other styles

11

Souza, Simone M. de, Franco Delle Monache, and Artur Smânia. "Antibacterial Activity of Coumarins." Zeitschrift für Naturforschung C 60, no. 9-10 (October 1, 2005): 693–700. http://dx.doi.org/10.1515/znc-2005-9-1006.

Full text

Abstract:

Abstract The antibacterial activity of coumarin per se and other 45 coumarin derivatives was tested against strains of Bacillus cereus MIP 96016, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, and Staphylococcus aureus ATCC 25923. The inhibitory effects of coumarins were affected by their substitution patterns. Osthenol (44) showed the most effective antibacterial activity against Gram-positive bacteria with MIC values ranging between 125 and 62.5 μg/ml. These results suggested that the prenyl chain of 44 at position 8 and the presence of OH at position 7 of the benzenic ring are required for the antibacterial activity against these strains.

APA, Harvard, Vancouver, ISO, and other styles

12

Olyaei, Abolfazl, Mahnaz Saraei, and Reyhaneh Khoeiniha. "Catalyst-Free One-Pot Synthesis of Novel Heteroarylamine Substituted Furo[3,2-c]coumarins." Synlett 29, no. 12 (May 17, 2018): 1589–92. http://dx.doi.org/10.1055/s-0036-1591582.

Full text

Abstract:

A high-yielding cyclocondensation of 4-hydroxycoumarin, phenylglyoxal monohydrate, and heteroarylamines proceeds without catalysis, which gives novel functionalized furo[3,2-c]coumarins and heteroarylamino alkylation of coumarin products in acetonitrile under reflux, is reported for the first time. This tandem process involves sequentially an aldol condensation, Michael addition, a ring closure, and dehydration reaction.

APA, Harvard, Vancouver, ISO, and other styles

13

Shahi, Akbar Massoumi, Mohammad Nikpassand, and Leila Zare Fekri. "Acidic Ionic Liquid-catalyzed Synthesis of Pyrano[4,3-b]pyran-5(4H)-ones using 4,4,4-trifluoro-1-phenylbutane-1,3-dione as a Building Block." Current Organic Synthesis 17, no. 8 (October 28, 2020): 648–53. http://dx.doi.org/10.2174/1570179417666200520111536.

Full text

Abstract:

Aims: synthesis of pyrano[c-2,3]chromens with Ionic Liquid catalyst with simple method. Background: Synthesis of pyrano[c]coumarins has a special place in the structure due to two bioactive compounds in its structure and attracts a great deal of attention in this research work, it has been attempted to attach chromatically valuable skeletons to them and synthesize the pyrano [c] coumarines, which can potentially have high biological properties. For this purpose, electrophilic β-ketoester ringing in the presence of ionic liquid catalysts was used. While optimizing the catalyst recovery, it is possible to synthesize several coumarine pyrano[ c]derivatives with high yield. Objective: This paper describes an efficient procedure for the multi-component reaction of aromatic aldehydes, 4,4,4-Trifluoro-1-phenyl-1,3-butanedione and 4-hydroxycoumarinwhich catalyzed by Ioniq liquid (OlmDSA), at room temperature. This catalyst was synthesized with new simple procedure. This protocol has advantages of simplicity, mild condition and high yield. Materials and Methods: After formation of a new stain corresponding to the alkene intermediate, 4-hydroxy coumarin (1 mM) was added. The reaction was progressed by thin layer chromatography in a 1: 2 ratio solvent containing ethyl acetate and hexane. The reaction mixture was then stirred for one hour. After the reaction was complete, the catalyst was first removed by washing. Ethanol was then added to the reaction residue and washed and finally filtered. The residual solid on the filter paper after drying was considered as the product and was taken to confirm. its structure, melting point and spectra. The following is a general overview of the reaction. Results and Discussion: In addition to the advantages mentioned for this tri-component reaction, the conservation of the coumarin ring is very important in this research design because it is formed in many of the reported open reactions and phenolic ring. Conclusion: The benefits of this work include simple reaction steps, review of reaction progress by TLC chromatography, simple separation of the catalyst by washing and reuse for three times without any reduction in yield and high reaction yield.

APA, Harvard, Vancouver, ISO, and other styles

14

Zhou, Li-Ping, and Ling-Liang Long. "7-Diethylamino-3-{(E)-4-[(E)-2-(pyridin-4-yl)ethenyl]styryl}-2H-chromen-2-one." Acta Crystallographica Section E Structure Reports Online 70, no. 2 (January 22, 2014): o176. http://dx.doi.org/10.1107/s1600536814001123.

Full text

Abstract:

In the title coumarin derivative, C28H26N2O2, the coumarin unit is approximately planar, with a maximum deviation of 0.048 (3) Å. The central benzene ring is oriented at dihedral angles of 30.15 (14) and 10.51 (11)°, respectively, to the pyridine ring and coumarin ring system. In the crystal, weak C—H...O and C—H...N hydrogen bonds and weak C—H...π interactions link the molecules into a three-dimensional supramolecular architecture.

APA, Harvard, Vancouver, ISO, and other styles

15

El-Sawy, Eslam Reda, Ahmed Bakr Abdelwahab, and Gilbert Kirsch. "Synthetic Routes to Coumarin(Benzopyrone)-Fused Five-Membered Aromatic Heterocycles Built on the α-Pyrone Moiety. Part II: Five-Membered Aromatic Rings with Multi Heteroatoms." Molecules 26, no. 11 (June 4, 2021): 3409. http://dx.doi.org/10.3390/molecules26113409.

Full text

Abstract:

Coumarins are natural heterocycles that widely contribute to the design of various biologically active compounds. Fusing different aromatic heterocycles with coumarin at its 3,4-position is one of the interesting approaches to generating novel molecules with various biological activities. During our continuing interest in assembling information about fused five-membered aromatic heterocycles, and after having presented mono-hetero-atomic five-membered aromatic heterocycles in Part I. The current review Part II is intended to present an overview of the different synthetic routes to coumarin (benzopyrone)-fused five-membered aromatic heterocycles with multi-heteroatoms built on the pyrone ring, covering the literature from 1945 to 2021.

APA, Harvard, Vancouver, ISO, and other styles

16

Kaur, Arvinder, Anju Goyal, Vishnu Nayak Badavath, Rajwinder Kaur, Sandeep Arora, and Ramninder Kaur. "Synthesis and Pharmacological Evaluation of Promising Coumarin Methyl Ester/ Di/Tri/Tetra Peptide Derivatives." ECS Transactions 107, no. 1 (April 24, 2022): 6747–61. http://dx.doi.org/10.1149/10701.6747ecst.

Full text

Abstract:

Coumarin is a phenol, consisting of benzene ring and alpha-pyrone ring. Coumarins are prepared through Pechmann reaction, which involve condensation of phenol with ethyl acetoacetate in the presence of acid catalyst. Coumarins are being used widely due to their various biological activities in recent years, like anticoagulant, antibacterial, antitumoral, antitubercular, antifungal, MAO inhibitor activity, antioxidant, anti-inflammatory and as CNS active compounds. Methyl esters of amino acids and their di/tri and tetrapeptides derivatives were prepared using coupling agent DCC and a base NMM by stirring continuously for 36 hours. The compounds prepared were analyzed and the structures are elucidated by TLC, IR and 1H NMR spectral data. They were screened for antibacterial activity against three bacterial species and antifungal activity against one species

APA, Harvard, Vancouver, ISO, and other styles

17

Walki, Shashikanth, S. Naveen, S. Kenchanna, K. M. Mahadevan, M. N. Kumara, and N. K. Lokanath. "Crystal structure of 8-ethoxy-3-(4-nitrophenyl)-2H-chromen-2-one." Acta Crystallographica Section E Crystallographic Communications 71, no. 11 (October 17, 2015): o860—o861. http://dx.doi.org/10.1107/s2056989015019325.

Full text

Abstract:

In the title compound, C17H13NO5, the coumarin ring system is essentially planar (r.m.s. deviation = 0.008 Å). The nitrophenyl ring makes a dihedral angle of 25.27 (9)° with the coumarin ring plane. The nitro group is almost coplanar with the phenyl ring to which it is attached, making a dihedral angle of 4.3 (3)°. The ethoxy group is inclined to the coumarin ring plane by 4.1 (2)°. Electron delocalization was found at the short bridging C—C bond with a bond length of 1.354 (2) Å. In the crystal, molecules are linkedviaC—H...O hydrogen bonds, forming sheets in thebcplane. The sheets are linkedviaπ–π stacking [centroid–centroid distances = 3.5688 (13) and 3.7514 (13) Å], forming a three-dimensional structure.

APA, Harvard, Vancouver, ISO, and other styles

18

Yang, Jian-Xin, Hong-Yan Liu, and Xiang-Hui Wang. "4-Methyl-2-oxo-2H-chromen-7-yl 4-methylbenzenesulfonate." Acta Crystallographica Section E Structure Reports Online 68, no. 4 (March 28, 2012): o1191. http://dx.doi.org/10.1107/s1600536812012238.

Full text

Abstract:

In the title compound, C17H14O5S, the coumarin ring system is nearly planar, with a maximum deviation of 0.034 (2) Å from the mean plane. The dihedral angle between the benzene ring and the coumarin ring system is 56.11 (6)°. The crystal packing is stabilized by C—H...O hydrogen bonding, which forms a three-dimensional framework.

APA, Harvard, Vancouver, ISO, and other styles

19

Devarajegowda, H. C., P. A. Suchetan, S. Sreenivasa, H. T. Srinivasa, and B. S. Palakshamurthy. "Crystal structure of 4-methoxyphenyl 2-oxo-2H-chromene-3-carboxylate." Acta Crystallographica Section E Crystallographic Communications 71, no. 6 (May 7, 2015): o374—o375. http://dx.doi.org/10.1107/s2056989015006970.

Full text

Abstract:

In the title compound, C17H12O5, the dihedral angle between the planes of the coumarin ring system (r.m.s. deviation = 0.015 Å) and the benzene ring is 48.04 (10)°. The central CO2group subtends a dihedral angle of 27.15 (11)° with the coumarin ring system and 74.86 (13)° with the benzene ring. In the crystal, molecules are linked by C—H...O interactions, which generate a three-dimensional network. Very weak C—H...π interactions are also observed.

APA, Harvard, Vancouver, ISO, and other styles

20

Bauri, A. K., Sabine Foro, Hans-Jörg Lindner, and Sandip K. Nayak. "Reinvestigation of seselin." Acta Crystallographica Section E Structure Reports Online 62, no. 4 (March 10, 2006): o1340—o1341. http://dx.doi.org/10.1107/s1600536806008221.

Full text

Abstract:

The crystal structure of seselin (2′,2′-dimethyl-3-pyreno[6,5:7,8]coumarin), C14H12O3, a bioactive pyrenocoumarin, has been reinvestigated. The coumarin ring system is nearly planar and the α-pyran ring adopts a distorted half-chair conformation. An intermolecular C—H...O hydrogen bond is observed.

APA, Harvard, Vancouver, ISO, and other styles

21

Sreenivasa, S., H. T. Srinivasa, B. S. Palakshamurthy, Vijith Kumar, and H. C. Devarajegowda. "4′-Cyanobiphenyl-4-yl 7-diethylamino-2-oxo-2H-chromene-3-carboxylate." Acta Crystallographica Section E Structure Reports Online 69, no. 2 (January 19, 2013): o266. http://dx.doi.org/10.1107/s1600536813001591.

Full text

Abstract:

In the title compound, C27H22N2O4, the dihedral angles between the central benzene ring and the cyanobenzene ring and the 2H-coumarin ring system (r.m.s. deviation = 0.014 Å) are 22.95 (11) and 75.59 (8)°, respectively. Both terminal C atoms of the pendant diethylamino group lie to the same side of the coumarin ring system [deviations = 1.366 (2) and 1.266 (2) Å]. In the crystal, molecules are linked by C—H...O and C—H...N hydrogen bonds and a C—H...π interaction, generating a three-dimensional network.

APA, Harvard, Vancouver, ISO, and other styles

22

Gouda, Moustafa A., Mohammed A. Salem, and Mohamed H. Helal. "A Review on Synthesis and Pharmacological Activity of Coumarins and Their Analogs." Current Bioactive Compounds 16, no. 6 (October 2, 2020): 818–36. http://dx.doi.org/10.2174/1573407215666190405154406.

Full text

Abstract:

Background: Coumarins were reported to possess antimicrobial, antiinflammatory, antiplasmodial, antimalarial, and enzyme inhibitory properties. Furthermore, coumarins are a type of vitamin K antagonists. Coumarins had been first organized through perkin reaction; besides Knoevenagel condensation was mentioned as a critical synthetic approach for the synthesis of 3-substituted coumarins. Moreover, Pechmann, Reformatasky and Witting reactions were stated for the preparation of coumarins. Methods: We undertook a structured search of the method of preparation, the chemical reactivity and biological properties that are associated with coumarins and their analogous. Results: Coumarins display a wide range of Src Kinase and cholinesterase inhibitor activities and application of coumarins as antidiabetic, antipsychotic and antiproliferative agents has been addressed. Other properties of coumarins such as their role in antitumor, anticancer, and as antioxidants have also been reviewed. Conclusion: This review concluded that coumarin ring was mixed with other rings, a synergistic effect for each of the ring in their biological activities was obtained, such compounds were exploited to improve various important molecules which provide scaffolds for drug improvement. These compounds were used to broaden a special molecule that gives scaffolds for drug improvement.

APA, Harvard, Vancouver, ISO, and other styles

23

Singh, Parvesh, Nomandla Ngcoya, Ramgopal Mopuri, Nagaraju Kerru, Neha Manhas, Oluwakemi Ebenezer, and Md Shahidul Islam. "α-Glucosidase Inhibition, Antioxidant and Docking Studies of Hydroxycoumarins and their Mono and Bis O-alkylated/acetylated Analogs." Letters in Drug Design & Discovery 15, no. 2 (January 30, 2018): 127–35. http://dx.doi.org/10.2174/1570180814666170602081941.

Full text

Abstract:

Background: Diabetes Mellitus (DM) is a complex metabolic disease illustrated by abnormally high levels of plasma glucose or hyperglycaemia. Accordingly, several α-glucosidase inhibitors have been developed for the treatment of diabetes and other degenerative disorders. While, a coumarin ring has the privilege to represent numerous natural and synthetic compounds with a wide spectrum of biological activities e.g. anti-cancer, anti-HIV, anti-viral, anti-malarial, anti-microbial, anti-convulsant, anti-hypertensive properties. Besides this, coumarins have also shown potential to inhibit α-glucosidase leading to a generation of new promising antidiabetic agents. However, the testing of O-substituted coumarins for α-glucosidase inhibition has evaded the attention of medicinal chemists. Methods: For O-alkylation/acetylation reactions, the hydroxyl coumarins (A-B) initially activated by K2CO3 in dry DMF were reacted with variedly substituted haloalkanes at room temperature under nitrogen. The synthesized compounds were tested for their α-glucosidase (from Saccharomyces cerevisiae) inhibitory activity and anti-oxidant activity using DPPH radical scavenging activity. In silico docking simulations were conducted using CDocker module in DS (Accelrys) to explore the binding modes of the representative compounds in the catalytic site of α-glucosidase. Results: All the coumarin analogues (A1, B1, A2-A10, B2-B8) including their precursors (A-B) were evaluated for their in vitro α-glucosidase inhibition using acarbose as a standard inhibitor. All the mono O-alkylated coumarins (except A1) showed significant (p <0.05) α-glucosidase inhibition relative to the hydroxyl coumarin (A) with IC50 values ranging between 11.084±0.117 to 145.24± 29.22 µg/mL. Compound 7-(benzyloxy)-4, 5-dimethyl-2H-chromen-2-one (A9) bearing a benzyl group (Ph-CH2-) at position 7 showed a remarkable (p <0.05) increase in the activity (IC50 = 11.084±0.117 µg/mL), almost four-fold more than acarbose (IC50 = 40.578±5.999 µg/mL). The introduction of –NO2 group dramatically improved the anti-oxidant activity of coumarin, while the O-alkylation/acetylation decreased the activity. Conclusion: The present study describes the synthesis of functionalized coumarins and their evaluation for α-glucosidase inhibition and antioxidant activity under in vitro conditions. Based on IC50 data, the mono O-alkylated coumarins were observed to be stronger inhibitors of α-glucosidase with respect to their bis O-alkylated analogues. Coumarin (A9) bearing O-benzyloxy group displayed the strongest α-glucosidase inhibition, even higher than the standard inhibitor acarbose. The coumarin (A10) bearing –NO2 group showed the highest anti-oxidant activity amongst the synthesized compounds, almost comparable to the ascorbic acid. Finally, in silico docking simulations revealed the role of hydrogen bonding and hydrophobic forces in locking the compounds in catalytic site of α-glucosidase.

APA, Harvard, Vancouver, ISO, and other styles

24

Choudhury, Sudip, Satya Paul, K. Majumdar, and Siddique Anwar. "Copper(I) Iodide Supported Synthesis of Coumarin- and Quinolone-Annulated 2-Aminothiazoles." Synlett 26, no. 08 (March 3, 2015): 1039–44. http://dx.doi.org/10.1055/s-0034-1380272.

Full text

Abstract:

An efficient and convenient method for the synthesis of coumarin- and quinolone-annulated 2-aminothiazoles is reported. The fused ring 2-aminothiazoles were synthesized from substituted coumarin/quinoline and phenylisothiocyanates in the presence of CuI, DABCO, and 1,10-phenanthroline. Both the rings in coumarin moiety supported the annulation by this method.

APA, Harvard, Vancouver, ISO, and other styles

25

Sinha, Shweta, Kuldeep Singh, Akash Ved, Syed Misbahul Hasan, and Samar Mujeeb. "Therapeutic Journey and Recent Advances in the Synthesis of Coumarin Derivatives." Mini-Reviews in Medicinal Chemistry 22, no. 9 (May 2022): 1314–30. http://dx.doi.org/10.2174/1389557521666211116120823.

Full text

Abstract:

Background: Coumarin is an oxygen-containing compound in medicinal chemistry. Coumarin plays an important role in both natural systems like plants and synthetic medicinal applications as drug molecules. Many structurally different coumarin compounds have been found to possess a wide range of similarities with the vital molecular targets in terms of their pharmacological action and small modifications in their structures, resulting in significant changes in their biological activities. Objective: This review provides detailed information regarding the studies focused on the recent advances in various pharmacological aspects of coumarins. Method: Various oxygen-containing heterocyclic compounds represent remarkable biological significance. The fused aromatic oxygen-heterocyclic nucleus can change its electron density, thus altering the chemical, physical and biological properties, respectively, due to its multiple binding modes with the receptors, which play a crucial role in the pharmacological screening of drugs. Several heterocyclic compounds have been synthesized which have their nuclei derived from various plants and animals. In coumarins, the benzene ring is fused with a pyrone nucleus which provides stability to the nucleus. Coumarins have shown a wide range of pharmacological activities, such as anti-tumor, anticoagulant, anti-inflammatory, anti-oxidant, antiviral, antimalarial, anti-HIV, antimicrobial, etc. Results: Reactive oxygen species, like superoxide anion, hydroxyl radical, and hydrogen peroxide, are a type of unstable molecule containing oxygen, which reacts with other molecules in the cell during metabolism; however, when the number of reactive oxygen species increases, it may lead to cytotoxicity, thereby damaging the biological macromolecules. Hydroxyl Radical (OH) is a strong oxidizing agent and it is responsible for the cytotoxicity caused by oxygen in different plants, animals, and other microbes. Coumarin is the oldest and effective compound having antimicrobial, anti-inflammatory, antioxidant, antidepressant, analgesic, anticonvulsant activities, etc. Naturally existing coumarin compounds act against SARS-CoV-2 by preventing viral replication and targeting the active site against the Mpro target protein. Conclusion: This review highlights the different biological activities of coumarin derivatives. In this review, we provide an updated summary of the researches which are related to recent advances in biological activities of coumarins analogs and their most recent activities against COVID -19. Natural compounds act as a rich resource for novel drug development against various SARS-CoV-2 viral strains and viruses, like herpes simplex virus, influenza virus, human immunodeficiency virus, hepatitis B and C viruses, middle east respiratory syndrome, and severe acute respiratory syndrome.

APA, Harvard, Vancouver, ISO, and other styles

26

do Nascimento, Jainara Santos, João Carlos Silva Conceição, and Eliane de Oliveira Silva. "Biotransformation of Coumarins by Filamentous Fungi: An Alternative Way for Achievement of Bioactive Analogs." Mini-Reviews in Organic Chemistry 16, no. 6 (August 27, 2019): 568–77. http://dx.doi.org/10.2174/1570193x15666180803094216.

Full text

Abstract:

Coumarins are natural 1,2-benzopyrones, present in remarkable amounts as secondary metabolites in edible and medicinal plants. The low yield in the coumarins isolation from natural sources, along with the difficulties faced by the total synthesis, make them attractive for biotechnological studies. The current literature contains several reports on the biotransformation of coumarins by fungi, which can generate chemical analogs with high selectivity, using mild and eco-friendly conditions. Prompted by the enormous pharmacological interest in the coumarin-related compounds, their alimentary and chemical applications, this review covers the biotransformation of coumarins by filamentous fungi. The chemical structures of the analogs were presented and compared with those from the pattern structures. The main chemical reactions catalyzed the insertion of functional groups, and the impact on the biological activities caused by the chemical transformations were discussed. Several chemical reactions can be catalyzed by filamentous fungi in the coumarin scores, mainly lactone ring opening, C3-C4 reduction and hydroxylation. Chunninghamella sp. and Aspergillus sp. are the most common fungi used in these transformations. Concerning the substrates, the biotransformation of pyranocoumarins is a rarer process. Sometimes, the bioactivities were improved by the chemical modifications and coincidences with the mammalian metabolism were pointed out.

APA, Harvard, Vancouver, ISO, and other styles

27

Karataş, Mert Olgun, Bülent Alıcı, Vincenzo Passarelli, Ismail Özdemir, Jesús J. Pérez-Torrente, and Ricardo Castarlenas. "Iridium(i) complexes bearing hemilabile coumarin-functionalised N-heterocyclic carbene ligands with application as alkyne hydrosilylation catalysts." Dalton Transactions 50, no. 32 (2021): 11206–15. http://dx.doi.org/10.1039/d1dt01946e.

Full text

Abstract:

Pentacoordinated iridium(i)-cyclooctadiene complexes featuring a coumarin-functionalised imidazoline– or benzimidazoline–NHC ligand exhibit fluxional behavior as a consequence of the hemilability of the pyrone ring in the coumarin wingtip.

APA, Harvard, Vancouver, ISO, and other styles

28

Paul, Saurav, Bimal B. Chakraborty, Kuheli Deb, and Sudip Choudhury. "FUSED RING HETEROCYCLE FUNCTIONALIZED GOLD NANOPARTICLES: SYNTHESIS AND SELF-ASSEMBLY." Chemical Problems 21, no. 2 (2023): 188–96. http://dx.doi.org/10.32737/2221-8688-2023-2-188-196.

Full text

Abstract:

Self-assembled nanoparticles are an area of great research prospect as they offer switchable element for designing and creating micro-scale constructs. Self-assembly of nano-hybrids through some noncovalent interactions such as electrostatic, π-π and van der Waal interactions in different classes of composite materials provide a great prospect of utilization of these functional properties in tailor-made device applications. In this work gold nanoparticle functionalized with coumarin based fused-ring heterocyclic thiol exhibiting self-assembly is reported. The present work has been designed giving prior to pi-stacking mediated self-aggregation of nanoparticles resulting formation of larger superstructures. The work reports the coumarin-based heterocyclic fused ring having a thiol anchoring group grafted to the gold nanoparticle surface for easier electron flow between the metal nanoparticle and the aromatic ligand and study their self-assembly nature.

APA, Harvard, Vancouver, ISO, and other styles

29

Liu, Yun, Yong-Miao Shen, Zhe Li, and Jian-Hua Xu. "2,4-Diphenyl-2-(trimethylsilyloxy)-3-dihydro-2H,5H-pyrano[3,2-c][1]benzopyran-5-one." Acta Crystallographica Section E Structure Reports Online 62, no. 4 (March 15, 2006): o1397—o1398. http://dx.doi.org/10.1107/s1600536806009020.

Full text

APA, Harvard, Vancouver, ISO, and other styles

30

Kothavale, Shantaram, and Nagaiyan Sekar. "A new type of triphenylamine based coumarin–rhodamine hybrid compound: synthesis, photophysical properties, viscosity sensitivity and energy transfer." RSC Advances 6, no. 107 (2016): 105387–97. http://dx.doi.org/10.1039/c6ra24485h.

Full text

Abstract:

A series of novel core modified triphenylamine coumarin–rhodamine systems (compounds MCMR, MCDR and DCMR) was designed and synthesized by incorporating a coumarin moiety on one and a rhodamine moiety on the other phenyl ring of the triphenylamine molecular skeleton.

APA, Harvard, Vancouver, ISO, and other styles

31

Quezada, Elías, Fernanda Rodríguez-Enríquez, Reyes Laguna, Elena Cutrín, Francisco Otero, Eugenio Uriarte, and Dolores Viña. "Curcumin–Coumarin Hybrid Analogues as Multitarget Agents in Neurodegenerative Disorders." Molecules 26, no. 15 (July 28, 2021): 4550. http://dx.doi.org/10.3390/molecules26154550.

Full text

Abstract:

Neurodegenerative diseases have a complex nature which highlights the need for multitarget ligands to address the complementary pathways involved in these diseases. Over the last decade, many innovative curcumin-based compounds have been designed and synthesized, searching for new derivatives having anti-amyloidogenic, inhibitory of tau formation, as well as anti-neuroinflammation, antioxidative, and AChE inhibitory activities. Regarding our experience studying 3-substituted coumarins with interesting properties for neurodegenerative diseases, our aim was to synthesize a new series of curcumin–coumarin hybrid analogues and evaluate their activity. Most of the 3-(7-phenyl-3,5-dioxohepta-1,6-dien-1-yl)coumarin derivatives 11–18 resulted in moderated inhibitors of hMAO isoforms and AChE and BuChE activity. Some of them are also capable of scavenger the free radical DPPH. Furthermore, compounds 14 and 16 showed neuroprotective activity against H2O2 in SH-SY5Y cell line. Nanoparticles formulation of these derivatives improved this property increasing the neuroprotective activity to the nanomolar range. Results suggest that by modulating the substitution pattern on both coumarin moiety and phenyl ring, ChE and MAO-targeted derivatives or derivatives with activity in cell-based phenotypic assays can be obtained.

APA, Harvard, Vancouver, ISO, and other styles

32

Journal, Baghdad Science. "Synthesis and Characterization of New Mannich Bases Derived from 7-hydroxy-4-methyl Coumarin." Baghdad Science Journal 13, no. 2 (June 5, 2016): 235–43. http://dx.doi.org/10.21123/bsj.13.2.235-243.

Full text

Abstract:

Coumarin is a natural substance isolated from different plants. It belonges to a group of benzobyrones which consists of a benzene ring joined to a pyrone nucleus. In the present research, a new series of coumarin derivatives were formed. Compound (1) (7-hydroxy-4-methyl Coumarin) was converted into 4-methylquinolin-2(H) derivative (2) by reaction with acetamide, and then reaction of (2) with thiosemicarbazide in ethanol leads to the synthesize of hydrazincarbothioamide derivative (3).The reaction of (3) with ethylchloroacetate in presence of sodium acetate leads to closure ring to get [(1-(5-oxo-2-thioxoimidazolidin-1-ylimino) ethyl)]quinolin-2(1H)-one (4). Mannich bases were prepared through the reaction of (4) with primary amines to form compounds (5-6). New coumarin derivatives were characterized by their physical properties and various spectral analysis like: FTIR, 1HNMR spectra and GC-Mass spectrum for some of them.

APA, Harvard, Vancouver, ISO, and other styles

33

Shao, Jiaan, Wenteng Chen, Di Ke, Ke Shu, En Chen, and Yongping Yu. "Highly Efficient Synthesis of Polysubstituted 2-Aminopyrroles via a Multicomponent Domino Reaction." Synlett 29, no. 07 (February 15, 2018): 922–27. http://dx.doi.org/10.1055/s-0036-1591907.

Full text

Abstract:

A highly efficient approach to polysubstituted 2-aminopyrroles containing a coumarin derivative unit at the 5-position of the pyrrole ring was developed via a novel multicomponent domino reaction of glyoxal monohydrate derivatives, anilines, coumarin derivatives, and malononitrile. This transformation proceeded via an α-aminoketone as the key intermediate.

APA, Harvard, Vancouver, ISO, and other styles

34

Ouédraogo, Mohammad, Akoun Abou, Abdoulaye Djandé, Olivier Ouari, and T. Jérémie Zoueu. "2-Oxo-2H-chromen-7-yl 4-tert-butylbenzoate." Acta Crystallographica Section E Crystallographic Communications 74, no. 4 (March 16, 2018): 530–34. http://dx.doi.org/10.1107/s2056989018004188.

Full text

Abstract:

In the title compound, C20H18O4, the benzoate ring is oriented at an acute angle of 33.10 (12)° with respect to the planar (r.m.s deviation = 0.016 Å) coumarin ring system. An intramolecular C—H...O hydrogen bond closes an S(6) ring motif. In the crystal, C—H...O contacts generate infinite C(6) chains along the b-axis direction. Also present are π–π stacking interactions between neighbouring pyrone and benzene rings [centroid–centroid distance = 3.7034 (18) Å] and C=O...π interactions [O...centroid = 3.760 (3) Å]. The data obtained from quantum chemical calculations performed on the title compound are in good agreement with the observed structure, although the calculated C—O—C—C torsion angle between the coumarin ring system and the benzoate ring (129.1°) is somewhat lower than the observed value [141.3 (3)°]. Hirshfeld surface analysis has been used to confirm and quantify the supramolecular interactions.

APA, Harvard, Vancouver, ISO, and other styles

35

Abou, Akoun, Jules Yoda, Abdoulaye Djandé, Stéphane Coussan, and T. Jérémie Zoueu. "Crystal structure of 2-oxo-2H-chromen-7-yl 4-fluorobenzoate." Acta Crystallographica Section E Crystallographic Communications 74, no. 5 (April 27, 2018): 761–65. http://dx.doi.org/10.1107/s205698901800614x.

Full text

Abstract:

In the title compound, C16H9FO4, (I), the benzene ring is oriented at an acute angle of 59.03 (15)° relative to the coumarin plane (r.m.s deviation = 0.009 Å). This conformation of (I) is stabilized by an intramolecular C—H...O hydrogen bond, which closes a five-membering ring. In the crystal, molecules of (I) form infinite zigzag chains along the b-axis direction, linked by C—H...O hydrogen bonds. Furthermore, the crystal structure is supported by π–π stacking interactions between neighbouring pyrone and benzene or coumarin rings [centroid–centroid distances in the range 3.5758 (18)–3.6115 (16) Å], as well as C=O...π interactions [O...centroid distances in the range 3.266 (3)–3.567 (3) Å]. The theoretical data for (I) obtained from quantum chemical calculations are in good agreement with the observed structure, although the calculated C—O—C—C torsion angle between the coumarin fragment and the benzene ring (73.7°) is somewhat larger than the experimental value [63.4 (4)°]. Hirshfeld surface analysis has been used to confirm and quantify the supramolecular interactions.

APA, Harvard, Vancouver, ISO, and other styles

36

Manojkumar, Parameswaran, Thengungal Ravi, and Gopalakrishnan Subbuchettiar. "Synthesis of coumarin heterocyclic derivatives with antioxidant activity and in vitro cytotoxic activity against tumour cells." Acta Pharmaceutica 59, no. 2 (June 1, 2009): 159–70. http://dx.doi.org/10.2478/v10007-009-0018-7.

Full text

Abstract:

Synthesis of coumarin heterocyclic derivatives with antioxidant activity andin vitrocytotoxic activity against tumour cellsThe aim of the present work was to synthesise coumarinyl heterocycles and to elucidate the potential role of these compounds as antioxidants and cytotoxic agents against Dalton's lymphoma ascites tumour cells (DLA) and Ehrlich ascites carcinoma cells (EAC). The synthesis of coumarin derivatives containing pyrazole, pyrazolone, thiazolidin-4-one, 5-carboxymethyl-4-thiazolidinone and 3-acetyl-1,3,4-oxadiazole ring is reported. 4-Methylcoumarinyl-7-oxyacetic acid hydrazide (1) reacted with arylazopropanes or hydrazono-3-oxobutyrate derivatives to form pyrazole (3a-c) and pyrazolone derivatives (5a-c). Heterocyclisation of Schiff's bases of 1 with thioglycolic acid, thiomalic acid or acetic anhydride afforded novel heterocyclic derivatives 4-thiazolidinones (7a-c), 5-carboxymethyl-4-thiazolidinones (8a-c) and oxadiazoles (9a-c), respectively. Some of the compounds showed promising antioxidant activityin vitroand cytotoxic activity against DLA cells and EAC cells.

APA, Harvard, Vancouver, ISO, and other styles

37

Gomes, Lígia R., John Nicolson Low, André Fonseca, Maria João Matos, and Fernanda Borges. "6-Methyl-2-oxo-N-(quinolin-6-yl)-2H-chromene-3-carboxamide: crystal structure and Hirshfeld surface analysis." Acta Crystallographica Section E Crystallographic Communications 72, no. 8 (July 12, 2016): 1121–25. http://dx.doi.org/10.1107/s2056989016011026.

Full text

Abstract:

The title coumarin derivative, C20H14N2O3, displays intramolecular N—H...O and weak C—H...O hydrogen bonds, which probably contribute to the approximate planarity of the molecule [dihedral angle between the coumarin and quinoline ring systems = 6.08 (6)°]. The supramolecular structures feature C—H...O hydrogen bonds and π–π interactions, as confirmed by Hirshfeld surface analyses.

APA, Harvard, Vancouver, ISO, and other styles

38

Zhang, Hengrui, and Zhijie Fang. "Design and Synthesis of Novel Vitamin D–Coumarin Hybrids using Microwave Irradiation." Journal of Chemical Research 41, no. 12 (December 2017): 684–87. http://dx.doi.org/10.3184/174751917x15121208772534.

Full text

Abstract:

A series of novel vitamin D–coumarin hybrids were synthesised by esterification of the corresponding coumarin-3-carboxylic acids and vitamin D or vitamin D CD-ring alcohol in CH2Cl2 under microwave irradiation. They were obtained in higher yields (from 64–81% up to 79–87%) and shorter reaction time (from 3 h down to 15 min), compared with earlier conventional methodologies. The structures of all the target compounds were confirmed by 1H NMR, 13C NMR and HRMS. This provides an attractive and alternative method for the preparation of high-value vitamin D–coumarin hybrids.

APA, Harvard, Vancouver, ISO, and other styles

39

Zhang, Kuan, Huabin Han, Lele Wang, Ziying Zhang, Qilin Wang, Wenjing Zhang, and Zhanwei Bu. "An unexpected cascade reaction of 3-hydroxyoxindoles with coumarin-3-carboxylates to construct 2,3-dihydrobenzofuran spirooxindoles." Chemical Communications 55, no. 91 (2019): 13681–84. http://dx.doi.org/10.1039/c9cc07114h.

Full text

APA, Harvard, Vancouver, ISO, and other styles

40

Tran, Nguyen Khoi Song, Tuy An Trinh, Jaesung Pyo, Chang Geon Kim, Jae Gyu Park, and Ki Sung Kang. "Neuroprotective Potential of Pyranocoumarins from Angelica gigas Nakai on Glutamate-Induced Hippocampal Cell Death." Antioxidants 12, no. 8 (August 21, 2023): 1651. http://dx.doi.org/10.3390/antiox12081651.

Full text

Abstract:

Chronic neurodegenerative diseases are typically associated with oxidative stress conditions leading to neuronal cell death. We aimed to investigate the neuroprotective effect of three pyranocoumarins (decursin, decursinol angelate, and decursinol) targeting oxidative stress factors. Decursin (also known as dehydro-8-prenylnaringenin) is a prenylated coumarin compound consisting of a coumarin ring system with a prenyl group attached to one of the carbons in the ring. As a secondary metabolite of plants, pyranocoumarin decursin from Angelica gigas Nakai presented protective effects against glutamate-induced oxidative stress in HT22, a murine hippocampal neuronal cell line. Decursinol (DOH) is a metabolite of decursin, sharing same coumarin ring system but a slightly different chemical structure with the prenyl group replaced by a hydroxyl group (-OH). In our findings, DOH was ineffective while decursin was, suggesting that this prenyl structure may be important for compound absorption and neuroprotection. By diminishing the accumulation of intracellular reactive oxygen species as well as stimulating the expression of HO-1, decursin triggers the self-protection system in neuronal cells. Additionally, decursin also revealed an anti-apoptotic effect by inhibiting chromatin condensation and reducing the forming of annexin-V-positive cells.

APA, Harvard, Vancouver, ISO, and other styles

41

Douka, Matina D., and Konstantinos E. Litinas. "An Overview on the Synthesis of Fused Pyridocoumarins with Biological Interest." Molecules 27, no. 21 (October 26, 2022): 7256. http://dx.doi.org/10.3390/molecules27217256.

Full text

Abstract:

Pyridocoumarins are a class of synthetic and naturally occurring organic compounds with interesting biological activities. This review focuses on the synthetic strategies for the synthesis of pyridocoumarins and presents the biological properties of those compounds. The synthesis involves the formation of the pyridine ring, at first, from a coumarin derivative, such as aminocoumarins, hydroxycoumarins, or other coumarins. The formation of a pyranone moiety follows from an existing pyridine or piperidine or phenol derivative. For the above syntheses, [4 + 2] cycloaddition reactions, multi-component reactions (MCR), as well as metal-catalyzed reactions, are useful. Pyridocoumarins present anti-cancer, anti-HIV, antimalarial, analgesic, antidiabetic, antibacterial, antifungal, anti-inflammatory, and antioxidant activities.

APA, Harvard, Vancouver, ISO, and other styles

42

Katopodi, Annita, Evangelia Tsotsou, Triantafylia Iliou, Georgia-Eirini Deligiannidou, Eleni Pontiki, Christos Kontogiorgis, Fotios Tsopelas, and Anastasia Detsi. "Synthesis, Bioactivity, Pharmacokinetic and Biomimetic Properties of Multi-Substituted Coumarin Derivatives." Molecules 26, no. 19 (October 2, 2021): 5999. http://dx.doi.org/10.3390/molecules26195999.

Full text

Abstract:

A series of novel multi-substituted coumarin derivatives were synthesized, spectroscopically characterized, and evaluated for their antioxidant activity, soybean lipoxygenase (LOX) inhibitory ability, their influence on cell viability in immortalized human keratinocytes (HaCaT), and cytotoxicity in adenocarcinomic human alveolar basal epithelial cells (A549) and human melanoma (A375) cells, in vitro. Coumarin analogues 4a–4f, bearing a hydroxyl group at position 5 of the coumarin scaffold and halogen substituents at the 3-phenyl ring, were the most promising ABTS•+ scavengers. 6,8-Dibromo-3-(4-hydroxyphenyl)-4-methyl-chromen-2-one (4k) and 6-bromo-3-(4,5-diacetyloxyphenyl)-4-methyl-chromen-2-one (3m) exhibited significant lipid peroxidation inhibitory activity (IC50 36.9 and 37.1 μM). In the DCF-DA assay, the 4′-fluoro-substituted compound 3f (100%), and the 6-bromo substituted compounds 3i (80.9%) and 4i (100%) presented the highest activity. The 3′-fluoro-substituted coumarins 3e and 4e, along with 3-(4-acetyloxyphenyl)-6,8-dibromo-4-methyl-chromen-2-one (3k), were the most potent lipoxygenase (LOX) inhibitors (IC50 11.4, 4.1, and 8.7 μM, respectively) while displaying remarkable hydroxyl radical scavenging ability, 85.2%, 100%, and 92.9%, respectively. In silico docking studies of compounds 4e and 3k, revealed that they present allosteric interactions with the enzyme. The majority of the analogues (100 μΜ) did not affect the cell viability of HaCaT cells, though several compounds presented over 60% cytotoxicity in A549 or A375 cells. Finally, the human oral absorption (%HOA) and plasma protein binding (%PPB) properties of the synthesized coumarins were also estimated using biomimetic chromatography, and all compounds presented high %HOA (>99%) and %PPB (60–97%) values.

APA, Harvard, Vancouver, ISO, and other styles

43

Justus, Eugen, Dana T. Izteleuova, Alexander V. Kasantsev, Mendel M. Axartov, Enno Lork, and Detlef Gabel. "Preparation of Carboranyl and Dodecaborate Derivatives of Coumarin." Collection of Czechoslovak Chemical Communications 72, no. 12 (2007): 1740–54. http://dx.doi.org/10.1135/cccc20071740.

Full text

Abstract:

A series of derivatives of coumarin (2H-chromen-2-one) and 6,7-benzocoumarin (3H-benzo-[f]chromen-3-one) carrying the o-carborane, m-carborane, and dodecaborate clusters, has been obtained. X-ray structure analysis has been carried out for three of the products. The addition of o-carborane occurs in the 4-position of the coumarin ring, in a stereoselective way, independent of whether the cluster was reacted as the lithium or magnesium salt. m-Carborane gives two products, one being the result of 1,2-addition to an exocyclic ester bond and 1,4-addition to the coumarin system, the other resulting from 1,4-addition. The negatively charged dodecaborate derivatives obtained, link the cluster via oxygen or sulfur and an appropriate linker to a 7-hydroxy-substituted coumarin. For the coumarin derivatives, an o-carboranecarbonyl derivative could also be obtained.

APA, Harvard, Vancouver, ISO, and other styles

44

Poronik, Yevgen M., and Daniel T. Gryko. "Pentacyclic coumarin-based blue emitters – the case of bifunctional nucleophilic behavior of amidines." Chem. Commun. 50, no. 43 (2014): 5688–90. http://dx.doi.org/10.1039/c4cc01106f.

Full text

APA, Harvard, Vancouver, ISO, and other styles

45

Pujar, Kiran K., Manohar V. Kulkarni, and G. N. Anil Kumar. "Crystal structure of 6,6′-dimethyl-2H,2′H-3,4′-bichromene-2,2′-dione." Acta Crystallographica Section E Structure Reports Online 70, no. 11 (October 11, 2014): 319–21. http://dx.doi.org/10.1107/s1600536814021825.

Full text

Abstract:

In the title compound, C20H14O4, the dihedral angle between the two coumarin ring systems is 52.37 (19)°, showing agauchearrangement across the C—C bond which links the two units. The carbonyl groups of the two coumarin units adopt an s-transarrangement. In the crystal, pairs of C—H...O hydrogen bonds and π–π interactions [centroid–centroid distance = 3.631 (2) Å] connect the molecules into inversion dimers.

APA, Harvard, Vancouver, ISO, and other styles

46

Sun, Zhiyuan, Yu Wang, De-Cai Fang, and Yuxia Zhao. "The effects of bromine atoms on the photophysical and photochemical properties of 3-cinnamoylcoumarin derivatives." New Journal of Chemistry 42, no. 9 (2018): 7377–82. http://dx.doi.org/10.1039/c8nj00966j.

Full text

APA, Harvard, Vancouver, ISO, and other styles

47

Chai, Lan-Qin, Hong-Song Zhang, Yu-Li Zhang, and Kai Cui. "Synthesis of Asymmetric Semicarbazides using a Coumarin Ring." Journal of Chemical Research 36, no. 1 (January 2012): 12–14. http://dx.doi.org/10.3184/174751912x13249848731931.

Full text

APA, Harvard, Vancouver, ISO, and other styles

48

Tlenkopatchev, Mikhail A., Serguei Fomine, Lioudmila Fomina, Ruben Gaviño, and Takeshi Ogawa. "Ring-Opening Metathesis Polymerization of Coumarin-Containing Norbornene." Polymer Journal 29, no. 7 (July 1997): 622–25. http://dx.doi.org/10.1295/polymj.29.622.

Full text

APA, Harvard, Vancouver, ISO, and other styles

49

Fang, Mingxi, Rashmi Adhikari, Jianheng Bi, Wafa Mazi, Nethaniah Dorh, Jianbo Wang, Nathan Conner, et al. "Fluorescent probes for sensitive and selective detection of pH changes in live cells in visible and near-infrared channels." Journal of Materials Chemistry B 5, no. 48 (2017): 9579–90. http://dx.doi.org/10.1039/c7tb02583a.

Full text

APA, Harvard, Vancouver, ISO, and other styles

50

Murdock, Daniel, Rebecca A. Ingle, Igor V. Sazanovich, Ian P. Clark, Yu Harabuchi, Tetsuya Taketsugu, Satoshi Maeda, Andrew J. Orr-Ewing, and Michael N. R. Ashfold. "Contrasting ring-opening propensities in UV-excited α-pyrone and coumarin." Physical Chemistry Chemical Physics 18, no. 4 (2016): 2629–38. http://dx.doi.org/10.1039/c5cp06597f.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Coumarin ring'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles