- Coumarins: Facile and expeditious synthesis via keggin-type heteropolycompounds under solvent-free condition
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Different Keggin-type heteropolycompounds were used in Pechmann reaction to obtain biologically active coumarins. Effect of solvent, catalyst loading, and molar ratios of substrates was studied to introduce the best reaction condition. The optimized reaction condition was extended to Pechmann reaction of methylacetoacetate with various monohydric and polyhydric phenols. This rapid procedure afforded structurally diverse coumarins with high to excellent yields. Short reaction times, simple work-up, and mild reaction conditions were advantages of this method. The optimized catalysts were reusable for four runs.
- Rafiee, Ezzat,Fakhri, Akram,Joshaghani, Mohammad
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- Targeted photoresponsive TiO2-coumarin nanoconjugate for efficient combination therapy in MDA-MB-231 breast cancer cells: Synergic effect of photodynamic therapy (PDT) and anticancer drug chlorambucil
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Coupling of photodynamic therapy (PDT) with chemotherapy is an emerging treatment modality because of its ability to improve the antitumor effect and reduce the toxicity of the anticancer agents. Metallic NPs, silica NPs and carbon nanotubes have become r
- Gangopadhyay, Moumita,Mukhopadhyay, Sourav K.,Karthik,Barman, Shrabani,Pradeep Singh
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- Novel coumarins and benzocoumarins acting as isoform-selective inhibitors against the tumor-associated carbonic anhydrase IX
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A series of coumarins and benzocoumarins incorporating methyl and hydroxyl moieties in the heterocyclic ring were investigated for the inhibition of the zinc enzyme carbonic anhydrase (CA, EC 4.2.1.1). These coumarins were very weak or ineffective as inhibitors of the house-keeping, offtarget isoforms CA I and II, but showed effective, submicromolar inhibition of the transmembrane, tumor-associated isoforms CA IX and to a slightly less extent, CA XII. The nature and position of the groups substituting the coumarin ring influenced CA inhibitory properties. 4-Methyl-5,7-dihydroydroxycoumarin showed KIs >200 μM against CA I and II, of 0.19 μM against CA IX and of 6.4 μM against CA XII, being thus a selective, efficient inhibitor for the tumor-associated over cytosolic CA isoforms. These compounds are interesting leads for designing isoform-selective enzyme inhibitors.
- Sharma, Aditi,Tiwari, Meena,Supuran, Claudiu T.
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- Reactions of 4-methylchromene-2,7,8-trione with phosphonium ylides. Synthesis and evaluation of fused 1,3-dioxolocoumarins as antioxidants and antiinflammatories
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4-Methylchromene-2,7,8-trione 1 reacts with stabilized 2a-c and non-stabilized ylides 11a-c bearing an α-methylene group to give 7,8-fused 1,3-dioxolocoumarins 4a-c and 12a-c along with betaine 6 and 7-hydroxycoumarin derivative 9. The reaction of 4,5-fused 1,3-dioxolo-o-benzoquinone 13 with the ylide 14 leads to 4-ethoxycarbonylayapin 18 and benzofuranone 19. Deethoxycarbonylation of 18 gives ayapin 20. Compounds 4b, 12a-c, 18 and 20 were tested for their ability to interact with 1,1-diphenyl-2-picrylhydrazyl stable free radical (DPPH), to scavenge superoxide anion radicals, to compete with DMSO for hydroxyl radicals, and to inhibit proteolysis, β-glucuronidase and soybean lipoxygenase activity in vitro. These compounds were also tested for their effect on the ferrous ion-stimulated peroxidation of linoleic acid. They showed a potent inhibitory effect (55-57%) against inflammation induced by carrageenan in the rat paw edema model. On the contrary their reducing ability was found to be low and no inhibition on soybean lipoxygenase was recorded.
- Fylaktakidou, Konstantina C.,Gautam, Daman R.,Hadjipavlou-Litina, Dimitra J.,Kontogiorgis, Christos A.,Litinas, Konstantinos E.,Nicolaides, Demetrios N.
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- FeCl3-catalyzed Pechmann synthesis of coumarins in ionic liquids
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The synthesis of coumarin derivatives via Pechmann reaction using anhydrous FeCl3 as Lewis acid catalyst in ionic liquid medium has been carried out. The best results were obtained (yields as high as 89%) with ionic liquids having bis(triflic)imide as a counteranion. The ionic liquid could easily be recovered and reused. Copyright Taylor & Francis Group, LLC.
- Kumar, Vineet,Tomar, Shilpi,Patel, Ronak,Yousaf, Ahmad,Parmar, Virinder S.,Malhotra, Sanjay V.
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- Recyclable CMK-5 supported sulfonic acid as an environmentally benign catalyst for solvent-free one-pot construction of coumarin through Pechmann condensation
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Sulfonic acid modified nanostructured CMK-5 is used as an alternative to conventional acid catalysts in the von Pechmann condensation of a neat mixture of substituted phenols with ethyl acetoacetate leading to the formation of coumarin derivatives at 130 °C. In comparison, CMK-5-SO3H showed a greater activity than some other homogeneous and heterogeneous catalysts. Additionally, the catalyst is reused repeatedly for 6 reaction cycles without any evidence of loss of activity, confirming the stability of the covalent bonding of acidic centers. The methodology presented offers reusable strategy for the efficient synthesis of coumarin, simplicity in operation, and green aspects by avoiding toxic conventional catalysts and solvents.
- Zareyee, Daryoush,Serehneh, Mahshad
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- Protein acyltransferase function of purified calreticulin. Part 1: Characterization of propionylation of protein utilizing propoxycoumarin as the propionyl group donor
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We have earlier reported that an endoplasmic reticulum luminal protein calreticulin (CR) mediated the acetylation of certain receptor proteins such as glutathione S-transferase (GST) by polyphenolic acetates, leading to irreversible inhibition. This function of calreticulin was termed calreticulin transacetylase. In this communication, we have demonstrated for the first time the ability of the purified recombinant calreticulin of a parasitic nematode Haemonchus contortus to transfer propionyl group from 7,8-Dipropoxy-4- methylcoumarin (DPMC) to recombinant Schistosoma japonicum glutathione S-transferase (rGST). Calreticulin transacetylase exhibited hyperbolic kinetics and yielded Km (140 μM) and Vmax (105 units) when the concentration of DPMC was varied keeping the concentration of rGST constant. rGST thus propionylated was found to positively interact with anti-acetyl lysine antibody. Also, the nanoscale LC-MS/MS analysis identified the propionylation sites on three lysine residues: Lys-11, -180 and -181 of rGST. These results highlight the transacylase function of calreticulin (CRTAase). The Authors 2009. Published by Oxford University Press on behalf of the Japanese Biochemical Society. All rights reserved.
- Singh, Prabhjot,Ponnan, Prija,Krishnan, Shibu,Tyagi, Tapesh Kumar,Priya, Nivedita,Bansal, Seema,Scumaci, Domenica,Gaspari, Marco,Cuda, Giovanni,Joshi, Paritosh,Gambhir, Jasvinder Kaur,Saluja, Daman,Prasad, Ashok Kumar,Saso, Luciano,Rastogi, Ramesh Chandra,Parmar, Virinder Singh,Raj, Hanumantharao Guru
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- Novel Fe3+-based 1H MRI β-galactosidase reporter molecules
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There is increasing interest in the development of reporter agents to reveal enzyme activity in vivo using imaging in small animals. We have previously demonstrated the feasibility of detecting lacZ gene activity using the commercially available 3,4-cyclohexenoesculetin-β-D-galactopyranoside (S-Gal) as a 1H MRI reporter. Specifically, β-galactosidase (β-gal) releases the aglycone, which forms a magnetic resonance contrast-inducing paramagnetic precipitate in the presence of Fe3+. Contrast was primarily T2-weighted signal loss, but T1 effects were also observed. Since T1-contrast generally provides signal enhancement as opposed to loss, it appeared attractive to explore whether analogues could be generated with enhanced characteristics. We now report the design and synthesis of novel analogues together with characterization of 1H MRI contrast based on both T1 and T2 response to b-gal activity in vitro for the lead agent.
- Yu, Jian-Xin,Gulaka, Praveen K.,Liu, Li,Kodibagkar, Vikram D.,Mason, Ralph P.
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- Acetoxy drug: Protein transacetylase catalyzed activation of human platelet nitric oxide synthase by polyphenolic peracetates
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An enhanced intracellular level of Nitric oxide (NO) is essential to ameliorate several pathological conditions of heart and vasculature necessitating the activation of NOS. We have projected in this report the acetylation of eNOS by polyphenolic peracetates (PA) catalyzed by the novel enzyme acetoxy drug: protein transacetylase (TAase) discovered in our laboratory as an unambiguous way of activating NOS which results in the manifestation of physiological action. The human platelet was chosen as the experimental system in order to validate the aforementioned proposition. PA caused profound irreversible activation of platelet NADPH cytochrome c reductase mediated by TAase. The convincing biochemical evidences are presented to show that PA could cause acetylation of the reductase domain of NOS leading to the activation of eNOS in tune with their specificities to platelet TAase. As a result, the enhanced level of NO due to activation of platelet eNOS by PA was found to inhibit the ADP-induced platelet aggregation. The present studies highlight for the first time the role of PA as the novel potent agent for enhancing the intracellular NO levels.
- Khurana, Pulkit,Kumari, Ranju,Vohra, Parag,Kumar, Ajit,Seema,Gupta, Garima,Raj, Hanumantharao G.,Dwarakanath, Bilikere S.,Parmar, Virinder S.,Saluja, Daman,Bose, Mridula,Vij, Anjana,Chaudhary, Nabo K.,Adhikari, Jawahar S.,Tyagi, Yogesh K.,Kohli, Ekta
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- Regioselective IBX-Mediated Synthesis of Coumarin Derivatives with Antioxidant and Anti-influenza Activities
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Different catechol and pyrogallol derivatives have been synthesized by oxidation of coumarins with 2-iodoxybenzoic acid (IBX) in DMSO at 25 °C. A high regioselectivity was observed in accordance with the stability order of the incipient carbocation or radical benzylic-like intermediate. The oxidation was also effective in water under heterogeneous conditions by using IBX supported on polystyrene. The new derivatives showed improved antioxidant effects in the DPPH test and inhibitory activity against the influenza A/PR8/H1N1 virus. These data represent a new entry for highly oxidized coumarins showing an antiviral activity possibly based on the control of the intracellular redox value.
- Bizzarri, Bruno M.,Botta, Lorenzo,Capecchi, Eliana,Celestino, Ignacio,Checconi, Paola,Palamara, Anna T.,Nencioni, Lucia,Saladino, Raffaele
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- Mechanism of biochemical action of substituted 4-methylbenzopyran-2- ones. Part 6: Hydrolysis of 7,8-diacetoxy-4-methylcoumarin by a novel deacetylase in rat liver microsomes - A simple method for assay and characterisation
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The existence of a novel microsomal deacetylase in rat liver catalysing deacetylation of diacetoxy 4-methylcoumarins has been reported. A simple method is outlined for the enzyme assay based upon the quantification of the dihydroxy derivative by measuring the UV absorption of its complex with ADP and Fe3+ at 600 nm. The enzyme can be routinely assayed using 7,8- diacetoxy-4-methylcoumarin (DAMC) as the substrate and demonstrated hyperbolic kinetics and yielded K(m) and V(max) values of 1250 μM and 500 units, respectively. The pH optima was found to be 7.5 for the enzyme. No DAMC deacetylase activity was found in hepatic cytosol and the enzyme activity was not discernible in extrahepatic tissues. (C) 2000 Elsevier Science Ltd.
- Raj, Hanumantha Rao G.,Parmar, Virinder S.,Jain, Subhash C.,Goel, Sanjay,Tyagi, Yogesh K.,Sharma, Sunil K.,Olsen, Carl E.,Wengel, Jesper
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- Nano-BFn/cellulose: a bio-based nano-catalyst for synthesis of bio-active 7-hydroxycoumarins
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Nano-BFn/cellulose as a modified bio-based nano-catalyst has been synthesized from nanocellulose and boron triflouride via very simple steps. This novel nano-catalyst exhibited many advantages in the synthesis of 7-hydroxycoumarins such as good
- Mirjalili, Bi Bi Fatemeh,Bamoniri, Abdolhamid,Fazeli-Attar, Seyede Azita
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p. 839 - 851
(2022/01/20)
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- Preparation of a novel, efficient, and recyclable magnetic catalyst, Cu(II)-OHPC-Fe3O4 nanoparticles, and a solvent-free protocol for the synthesis of coumarin derivatives
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Cu(II) supported on 5-oxo-4,5-dihydro-pyrrole-3-carboxylic acid functionalized Fe3O4 nanoparticles (Cu(II)-OHPC-Fe3O4) as a new magnetic nanocatalyst was prepared and characterized by ICP-AES, FT-IR, XRD, SEM, TEM, TGA, XRD, VSM and EDX techniques. Prepared nanocatalyst (Cu(II)-OHPC-Fe3O4) is employed for Pechmann reactions between different substituted phenols and ethyl acetoacetate to obtain new products of coumarin derivatives in good to excellent yields. This green catalyst was easily removed, reused several times with no significant loss of its activity and provided clean synthesis with excellent yield and reduced time.
- Yuan, Jingjing,Mohammadnia, Majid
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p. 2327 - 2343
(2021/07/26)
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- Synthesis of C4-substituted coumarins via Pechmann condensation catalyzed by sulfamic acid. Insights into the reaction mechanism by HRMS analysis
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A series of functionalized C4-substituted coumarins were synthesized by exploring the reaction of activated and non-activated phenols and β-ketoesters under solvent-free conditions in the presence of sulfamic acid as a Br?nsted acid catalyst. Fifteen exam
- Moraes, Maiara C.,Lenard?o, Eder J.,Barcellos, Thiago
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p. 151 - 163
(2022/01/28)
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- Antagonistic activity of hydroxycoumarin-based antioxidants as possible singlet oxygen precursor photosensitizers
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Coumarins are phenolic-type compounds with efficient antioxidant activity due to their ability to scavenge reactive oxygen species. Nevertheless, their ability to behave as photosensitizers capable of generating reactive oxygen species, such as singlet oxygen, has been less studied. In this work, the photosensitizing ability of seven hydroxycoumarins was evaluated through the photooxidation of ergosterol by quantifying the conversion of ergosterol into ergosterol peroxide. In our experimental conditions, we found that almost every tested antioxidant coumarin promotes the peroxidation of ergosterol. The results suggest that the hydroxycoumarins exhibit potential photosensitizing activity by promoting singlet oxygen generation by a Type II photochemical mechanism. Density functional theory (DFT) calculations were also performed to obtain further insight into the chemical reactivity of tested compounds; the observed tendency in the group of antioxidant coumarins to promote the reaction was their hardness due to the principle of maximum hardness. To evaluate our conclusion, we performed the reaction using a highly polarizable coumarin as a photosensitizer, which resulted in an increased photosensitizing capacity supported with DFT calculations, which reinforces our analysis. Finally, we found that hydroxycoumarins can be potentially pro-oxidants since some of them can act as photosensitizers and generate singlet oxygen in the presence of UV–Vis light, a characteristic that must be considered when these compounds are used as antioxidants.
- Guerrero, Tomás,Vázquez-Ortega, Fernanda,Lagunes, Irene,Ortiz-Blanco, Erik,Sosa-Ortiz, Gabriela,Tovar-Miranda, Ricardo,Medina, Manuel E.,Trigos, ángel
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- B(C6F5)3-catalyzed synthesis of coumarins via Pechmann condensation under solvent-free conditions
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Tris(pentafluorophenyl)borane [B(C6F5)3] catalyzed simple, efficient and environmentally benign protocol has been developed for the Pechmann condensation using variety of phenols and β-ketoesters under solvent-free conditions to afford coumarin derivatives. The present protocol displayed significant advantages such as low catalyst loading, short reaction time, mild reaction conditions, low toxicity, easy work-up, high yields, and compatibility with other functional groups. In addition, it is a convenient, clean, and fast alternative approach for synthesizing variety of coumarin derivatives. Moreover, the applicability of this method towards large-scale synthesis demonstrated its suitability for the industrial application. Graphic abstract: [Figure not available: see fulltext.]
- Prajapti, Santosh Kumar,Rao, S. Prakash
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p. 469 - 473
(2021/03/26)
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- Synthesis and structure-activity relationship of coumarins as potent Mcl-1 inhibitors for cancer treatment
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Myeloid cell leukemia-1 (Mcl-1) is a validated and attractive target for cancer therapy. Over-expression of Mcl-1 in many cancers allows cancer cells to evade apoptosis and contributes to their resistance to current chemotherapeutics. In this study, more than thirty coumarin derivatives with different substituents were designed and synthesized, and their Mcl-1 inhibitory activities evaluated using a fluorescence polarization-based binding assay. The results showed that the catechol group was a key constituent for Mcl-1 inhibitory activity of the coumarins, and methylation of the catechol group led to decreased inhibitory activity. The introduction of a hydrophobic electron-withdrawing group at the C-4 position of 6,7-dihydroxycoumarin, enhanced Mcl-1 inhibitory capacity, and a hydrophilic group in this position was unbeneficial to the inhibitory potency. In addition, the introduction of a nitrogen-containing group to the C-5 or C-8 position, which allowed an intramolecular hydrogen bond, was also unfavorable for Mcl-1 inhibition. Among all coumarins tested, 4-trifluoromethyl-6,7-dihydroxycoumarin (Cpd 4) displayed the most potent inhibitory activity towards Mcl-1 (Ki = 0.21 ± 0.02 μM, IC50 = 1.21 ± 0.56 μM, respectively), for which the beneficial effect on taxol resistance was also validated in A549 cells. A strong interaction between Cpd 4 and Mcl-1 in docking simulations further supported the observed potent Mcl-1 inhibition ability of Cpd 4. 3D-QSAR analysis of all tested coumarin derivatives further provides new insights into the relationships linking the inhibitory effects on Mcl-1 and the steric-electrostatic properties of coumarins. These findings could be of great value for medicinal chemists for the design and development of more potent Mcl-1 inhibitors for biomedical applications.
- Xia, Yang-Liu,Wang, Jing-Jing,Li, Shi-Yang,Liu, Yong,Gonzalez, Frank J.,Wang, Ping,Ge, Guang-Bo
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- MnSb2O6-chitosan nanocomposite: An efficient catalyst for the synthesis of coumarins via Pechmann reaction
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In this work, MnSb2O6-chitosan nanocomposites were synthesized and have been employed in Pechmann condensation for the synthesis of coumarin derivatives. MnSb2O6-chitosan nanocomposites were characterized by Fou
- Bahramnezhad, Baharak,Ghazanfari, Dadkhoda,Sheikhhosseini, Enayatollah,Akhgar, Mohammad Reza,Ahmadi, Sayed Ali
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supporting information
p. 173 - 181
(2019/11/20)
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- Synthesis of coumarin derivatives in a microfluidic flow system employing the Pechmann condensation: A case study
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For the synthesis of coumarin derivatives using the Pechmann condensation scheme, an acidic ionic liquid catalyst, abbreviated as [EBsImH][HSO4], was prepared from the ring opening of 1,4-butanesultone by 1-ethylimidazole, followed by the addition of 1 equiv. H2SO4(c). The [EBsImH][HSO4]-catalyzed Pechmann condensation reactions proceeded smoothly in a batch setup, with recyclable [EBsImH][HSO4] showing great catalytic activity. The acidic ionic liquid catalyst [EBsImH][HSO4] was recovered from EtOAc/H2O extraction of the product mixture, where the H2O layer was worked up and dried for reuse in consecutive runs of the Pechmann condensation reactions, maintaining >85% conversion for four times. The catalytic reactions were also carried out in a microfluidic flow setup. The flow parameters, the reactant molar amounts, and the additional H2SO4 as a modifying acid catalyst were optimized in the current case study. A minimum conversion rate of 2.8 g/hr of coumarin derivatives was demonstrated.
- Liu, Ling-Kang,Deng, Jhao-Hong,Guo, Yang-Ming
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p. 2208 - 2215
(2020/11/30)
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- Agonist daphnetin derivative, pharmaceutical composition and application thereof
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The invention provides an agonist daphnetin derivative, a pharmaceutical composition and application thereof. The daphnetin derivatives (1-9) or the pharmaceutically acceptable salt or solvent compound thereof are represented by the following formula defined in the specification. The pharmaceutical composition comprises the daphnetin derivative or the pharmaceutically acceptable salt or solvent compound thereof as an active ingredient, and a pharmaceutically acceptable carrier and/or excipient. According to the invention, the daphnetin derivative or the pharmaceutically acceptable salt or solvent compound thereof can be applied to preparation of drugs for treating neurodegenerative diseases, neuropathic pain, metabolic diseases and cancers and B-type G protein coupled receptor stimulant drugs; and the pharmaceutical composition is applied to preparation of drugs for treating rheumatoid arthritis, so that the application range of the daphnetin derivative is expanded.
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Paragraph 0096-0104
(2020/11/23)
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- Syntheses and evaluation of daphnetin derivatives as novel G protein-coupled receptor inhibitors and activators
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A series of daphnetin (7,8-dihydroxycoumarin) derivatives 1–22 were synthesized including sixteen new compounds (1–5, 7–14, 18, 21 and 22) and six known compounds (6, 15–17, 19 and 20). Their pharmacological activities on G protein-coupled receptors (GPCRs) were evaluated by double antibody sandwich ELISA (DAS-ELISA) in vitro. Daphnetin derivatives with various substitution patterns/groups were obtained from inhibitors to activators on GPCRs. Derivatives 2–5, 8, 15, 16 and 18–20 possessed moderate activation potency on GPCRs. Among them, derivatives 3–5, 16 and 19 presented significant activation potency on GPCRs with EC50 values in the range of 1.18–1.91 nM. Derivatives 6, 11, 14 and 18 showed significant inhibitory potency on GPCRs with IC50 values in the range of 1.26–1.38 nM. Moreover, the structure-activity relationships (SARs) of daphnetin derivatives were discussed in detail. The new daphnetic-based GPCRs activators and inhibitors have potentials as future drug candidates for the treatment of metabolic diseases.
- Wang, Yinan,Wang, Jiangming,Fu, Zhe,Sheng, Ruilong,Wu, Wenhui,Fan, Junting,Guo, Ruihua
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- Structure-based design and synthesis of new 4-methylcoumarin-based lignans as pro-inflammatory cytokines (TNF-α, IL-6 and IL-1β)inhibitors
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Suppression of pro-inflammatory cytokines (TNF-α, IL-1β and IL-6)along with nitric oxide reduction in RAW 264.7 cells by 7,8-dihydroxy-4-methylcoumarin, ethyl p-coumarate, ethyl caffeate and ethyl ferulate drove us to search structural-analogues of the aforementioned compounds through structure-based drug design. Docking studies revealed that substituted cinnamic acids and their ethyl esters (2-7c)showed higher GoldScore-fitness (GSF)and non-bonding interactions with target proteins than 7,8-dihydroxy-4-methylcoumarin (1a)and 7,8-dihydroxy-5-methylcoumarin (1b). With this background, the methylcoumarins (1a and 1b)and the cinnamic acid derivatives (2-7c)were fused in different permutations and combinations to generate sixty novel fused-cyclic coumarinolignans (FCLs)(8–13k). Docking studies on 8–13k indicated that several FCLs possess higher GSF, interesting active site interactions and distinctive π-π interactions compared to the standards (cleomiscosin A, diclofenac Na and prednisolone). Based on these findings, four novel FCLs (9d, 10d, 11d and 11e)were synthesized and tested for inhibition effect on TNF-α, IL-1β and IL-6 expressions in LPS and oxalate crystal-induced in-vitro models. Compound 10d exhibited significant effect (P 50 value of 8.5 μM against TNF-α. Compound 11e possessed IC50 values of 13.29 μM and 17.94 μM against IL-6 and IL-1β, respectively. Study on SAR corroborated the requirement of C-4-methyl substituent in the coumarin moiety, dihydroxyl groups in the phenyl ring, and esterification of lignans for potent activity. Additionally, the reported excellent anti-inflammatory activity of cleomiscosin-A-glucoside was corroborated by from the higher GSF and better hydrophobic interactions than cleomsicosin A in the docking study. As an outcome, some novel and potentially active FCLs acting through NFκB and caspase 1 signaling pathways have been discovered as multiple cytokine inhibitors.
- Santhosh Kumar,Sajeli Begum, Ahil,Hira, Kirti,Niazi, Sarfaraj,Prashantha Kumar,Araya, Hiroshi,Fujimoto, Yoshinori
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- Synthes?s and character?zat?on of new tr?azole and coumar?n-derived heterocycl?c compounds part I
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Synthesis of ethyl ester of acetic acid containing 5-oxo-[1,2,4] triazole ring (2) was achieved by the condensation of 3-substituted-4-amino-1H-1,2,4-triazol-5(4H)-one (1) with ethyl bromoacetate in basic medium. Compound 2, was then further reacted with hydrazine hydrate to form acid hydrazide, which is 2-(4-amino-3-substituted-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl)acetohydrazide (3). Compound 3 was later treated with three different diverse coumarin aldehydes (6, 12, 18) resulted in the formation of arylidene hydrazides as cis–trans conformers (7, 8, 13, 14, 19, 20). In conclusion, we synthesized 1,2,4-triazole Schiff bases derived from the condensation of 3-substituted-4-amino-1,2,4-triazole-5-on and formylhydroxy-4-methylcoumarin derivatives, which have been characterized by, spectroscopic measurements (IR, 1H-NMR, 13C-NMR and elemental analysis).
- Gümrük?üo?lu, Nurhan,Imran, Muhammad,Iqbal, Inam
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p. 1097 - 1106
(2020/01/09)
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- Recyclable cellulose nanocrystal supported Palladium nanoparticles as an efficient heterogeneous catalyst for the solvent-free synthesis of coumarin derivatives via von Pechmann condensation
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2-Amino pyrimidine nanocellulose-supported Palladium nanoparticles (CNC-AMPD-Pd) as a novel bio supported nanocatalyst was prepared and characterized by ICP-AES, FT-IR, XRD, SEM, TEM, TGA and EDX techniques. The nanocatalyst demonstrated outstanding performance in Pechmann condensation between different substituted phenols and ethyl acetoacetate to obtain coumarin derivatives in good to excellent yields. The catalyst is easily recycled and reused without loss of the catalytic activity. The combined merits of reusable catalyst and solvent-free reaction conditions make the condensation with safe operation, no leaching of pd into environment, low pollution, rapid access to products and simple workup.
- Mirosanloo, Atieh,Zareyee, Daryoush,Khalilzadeh, Mohammad A.
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- Anionic SO3H-functionalized ionic liquid: An efficient and recyclable catalyst for the Pechmann reaction of phenols with ethyl acetoacetate
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This paper has reported an anionic SO3H-functionalized ionic liquid N-methylimidazolium sulfomethylsulfonate ([Hmim][HO3SCH2SO3]) for the synthesis of coumarins by Pechmann reaction. The [Hmim][HO3SCH2SO3] is easier to prepare by one-step neutralization reaction of N-methylimidazole with methanedisulfonic acid and show high catalytic performance for Pechmann reaction. Besides, the catalyst can simply be separated from the reaction mixture and recycled ten times without noticeable loss of activity.
- Song, Dayong,Chen, Jing,Liang, Yong-Min
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supporting information
p. 692 - 698
(2018/02/16)
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- Synthesis method of coumarin compounds
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The invention relates to a synthesis method of coumarin compounds. The method particularly comprises the following steps: performing reaction for 40 to 120 minutes by taking substituted phenol and beta-keto ester as substrates and DES as a catalyst under the condition of no solvents and at the temperature of 50 to 100 DEG C to prepare the coumarin compounds. In the preparation process of the coumarin compounds, other organic solvents do not need to be added and the DES serves as a reaction catalyst and solvent. The DES can be reused and is environment-friendly, and the catalytic effect basically maintains unchanged after the DES is recovered for four times. The preparation method provided by the invention is simple in process, high in catalytic activity and high in yield; and after reaction, treatment is simple, convenient and environment-friendly.
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Paragraph 0058; 0059; 0061
(2018/06/23)
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- Synthesis and structure-activity relationship of daphnetin derivatives as potent antioxidant agents
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In this study, daphnetin 1 was chosen as the lead compound, and C-3 or C-4-substituted daphnetins were designed and synthesized to explore the potential relationship between the antioxidant activities and the chemical structures of daphnetin derivatives. The antioxidant activities of the generated compounds were evaluated utilizing the free radical scavenging effect on 2,2-diphenyl-1-picrylhydrazyl, 2,2-azinobis-(3-ethylbenzthiazoline-6-sulfonate) cation, and the ferric reducing power assays, and were then compared with those of the standard antioxidant Trolox. The results showed that the catechol group was the key pharmacophore for the antioxidant activity of the daphnetins. The introduction of an electron-withdrawing hydrophilic group at the C-4 position of daphnetin enhanced the antioxidative capacity, but this trend was not observed for C-3 substitution. In addition, introduction of a a hydrophobic phenyl group exerted negative effects on the antioxidant activity in both the C-3 and C-4 substitutions. Among all of the derivatives tested, the most powerful antioxidant was 4-carboxymethyl daphnetin (compound 9), for which the strongest antioxidant activity was observed in all of the assays. In addition, compound 9 also displayed strong pharmaceutical properties in the form of metabolic stability. To summarize, compound 9 holds great potential to be developed as an antioxidant agent with excellent antioxidant activity and proper pharmacokinetic behavior.
- Xia, Yangliu,Chen, Chen,Liu, Yong,Ge, Guangbo,Dou, Tongyi,Wang, Ping
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- A green and convenient approach for the one-pot solvent-free synthesis of coumarins and β-amino carbonyl compounds using Lewis acid grafted sulfonated carbon@titania composite
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Abstract: This paper reports an efficient protocol for the synthesis of coumarins via Pechmann reaction, and β-amino carbonyl compounds via aza-Michael reaction using catalytic amount of solid Lewis acid catalyst, C@TiO2–SO3–SbCl2. Six different catalysts were prepared by covalent immobilization of homogeneous Lewis acids onto sulfonated carbon@titania composite derived from amorphous carbon and nano-titania. Among various catalysts tested, C@TiO2–SO3–SbCl2 showed superior catalytic activity. The catalyst could be recycled without significant loss of its catalytic activity and demonstrated versatile catalysis for a wide range of substrates. Graphical abstract: [Figure not available: see fulltext.]
- Kour, Manmeet,Paul, Satya
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p. 327 - 337
(2017/02/10)
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- SnCl4 grafted on silica gel: an efficient catalyst for solvent-free synthesis of coumarins via the Pechmann condensation
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A facile synthesis of substituted coumarins via Pechmann condensation catalyzed by SnCl4 grafted on silica gel is described, which was conducted under solvent-free condition in high yields. The catalyst is noncorrosive and can be easily prepared and separated from the reaction mixture. This methodology offers some advantages with regard to yield of products, simplicity in operation and green aspects.
- Sun, Rui,Gao, Yanjuan,Ma, Ying,Yang, Guangde,Li, Yiping
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p. 737 - 742
(2017/01/17)
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- Nanosilica molybdic acid: synthesis, characterization and application as a green and reusable catalyst for the Pechmann condensation
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Abstract: Nanosilica molybdic acid (SMA NPs) was founded as an efficient and recyclable nanocatalyst for the synthesis of coumarin derivatives in excellent yields with good purity. Nano-SMA as a new solid acid was characterized by X-ray fluorescence, X-ray diffraction, energy-dispersive X-ray analyzer, transmission electron microscopy and Fourier transform infrared spectroscopy. Coumarin derivatives were obtained via the Pechmann condensation reaction of phenols and β-ketoesters at 80?°C under solvent-free conditions. The main advantages of the present procedure are high yields, shorter reaction time and green chemistry procedure, simple work-up and inexpensive and reusability of the catalyst. Graphical Abstract: [Figure not available: see fulltext.]
- Kiani, Mahtab,Karami, Bahador
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p. 655 - 663
(2017/01/17)
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- One-pot synthesis of coumarine derivatives using butylenebispyridinium hydrogen sulfate as novel ionic liquid catalyst
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Pechmann condensation reaction of 3-hydroxyphenol and ethyl acetoacetate in the presence of 1,1′‐butylenebispyridinium hydrogen sulfate as an efficient, green, and recyclable catalyst produces 7-hydroxy-4-methylcoumarin in good yield under solvent-free conditions at room temperature. This catalyst has advantages such as the following: good to excellent yields, short reaction times, simplicity in operation, and easy workup procedure.
- Rezayati, Sobhan,Sheikholeslami-Farahani, Fatemeh,Rostami-Charati, Faramarz,Abad, Saeid Afshari Sharif
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p. 4097 - 4107
(2016/07/06)
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- Meglumine sulfate catalyzed solvent-free one-pot synthesis of coumarins under microwave and thermal conditions
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A convenient method has been developed for the Pechmann reaction of phenols and β-keto esters catalyzed by meglumine sulfate. Solvent-free conditions, inexpensive catalyst, short reaction times, high yield, and ease of purification of the products are the advantages of this protocol. This novel catalytic system is expected to contribute to the development of more benign Pechmann condensation reactions of phenols with β-keto esters.
- Moradi, Leila,Rabiei, Khadijeh,Belali, Fateme
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supporting information
p. 1283 - 1291
(2016/08/16)
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- L-ascorbic acid: A green and competent promoter for solvent-free synthesis of flavones and coumarins under conventional as well as microwave heating
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Background: An expeditious approach has been developed for the synthesis of two distinct classes of benzopyrones viz. flavones and coumarins under solvent-free conditions. L-Ascorbic acid was found to be an effective promoter under microwave irradiation and conventional heating. Various benzo-α-pyrones and benzo-γ-pyrones were synthesized with overall good yields. The present protocol is highly facile and needs no column chromatography for purification and therefore it would serve as an effective and compatible method under both microwave irradiation and conventional heating. Results: The catalytic ability of L-ascorbic acid was investigated for the synthesis of flavones and coumarins. For this purpose, cyclodehydration of 1-(2-hydroxyphenyl)-3-aryl-1,3-propanedione and Pechmann coumarin synthesis, reactions were selected. And accordingly, it was observed that one mole of L-ascorbic acid was necessary for the completion of reaction. In all the cases, the desired flavones were smoothly generated with good to excellent yields; indicating its excellent tolerance for various functional groups. However, electron donating groups favors coumarin synthesis under these conditions. All the reaction mixtures were carefully analyzed and NMR indicates high conversions and lack of side products. Conclusion: We have developed L-ascorbic acid-promoted, solvent-free and simple method for the synthesis of benzo-α-pyrones and benzo-γ-pyrone under microwave irradiation as well as conventional heating in good to excellent yields. The notable advantages of this method are solvent-free conditions, inexpensive and efficient eco-friendly promoter, and shorter reaction time and can be carried out under air. This methodology is highly facile and requires no column chromatography for purification. The resulting flavones and coumarins are versatile building blocks in the construction of heterocyclic architectures, dominant in natural products. Further studies of exploiting the efficiency of L-ascorbic acid as a promoter in synthesis of various heterocyclic compounds are in progress.
- Dengale, Rohit Arvind,Thorat, Nitin Madhu,Thopate, Shankar Ramchandra
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p. 734 - 741
(2017/02/05)
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- Natural organic acids promoted green and expeditious synthesis of coumarins under solvent free condition
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Green and highly efficient synthesis of coumarins by Pechmann condensation, using naturally occurring acids under solvent free condition, is described. Various phenols efficiently condensed with ethyl acetoacetate under conventional as well as microwave i
- Rohokale, Sandeep V.,Kote, Santosh R.,Thopate, Shankar R.
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- Biocatalytic synthesis of novel partial esters of a bioactive dihydroxy 4-methylcoumarin by Rhizopus oryzae lipase (ROL)
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Highly regioselective acylation has been observed in 7,8-dihydroxy-4-methylcoumarin (DHMC) by the lipase from Rhizopus oryzae suspended in tetrahydrofuran (THF) at 45°C using six different acid anhydrides as acylating agents. The acylation occurred regioselectively at one of the two hydroxy groups of the coumarin moiety resulting in the formation of 8-acyloxy-7-hydroxy-4-methylcoumarins, which are important bioactive molecules for studying biotansformations in animals, and are otherwise very difficult to obtain by only chemical steps. Six monoacylated, monohydroxy 4-methylcoumarins have been biocatalytically synthesised and identified on the basis of their spectral data and X-ray crystal analysis.
- Kumar, Vinod,Mathur, Divya,Srivastava, Smriti,Malhotra, Shashwat,Rana, Neha,Singh, Suraj K.,Singh, Brajendra K.,Prasad, Ashok K.,Varma, Anjani J.,Len, Christophe,Kuhad, Ramesh C.,Saxena, Rajendra K.,Parmar, Virinder S.
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- Sulfonated core-shell magnetic nanoparticle (Fe3O4@SiO2@PrSO3H) as a highly active and durable protonic acid catalyst; Synthesis of coumarin derivatives through pechmann reaction
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Sulfonic acid supported silica coated magnetic nanoparticles (Fe3O4@SiO2@PrSO3H), was prepared by using low cost precursors and a facile immobilization technique. The final catalyst, which was characterized by XRD, FT-IR, vibrating sample magnetometer (VSM), TEM, and TGA techniques, was found to be an efficient and environmentally benign solid acid for the Pechmann condensation of substituted phenols with ethyl acetoacetate leading to the formation of coumarin derivatives. After the reaction, the catalyst could be effortlessly separated by external magnet and reused for 22 consecutive runs, without any significant loss in catalytic efficiency. The catalytic system presented offers a reusable strategy for the efficient synthesis of coumarin, simplicity in operation, and a green reaction profile by avoiding toxic conventional catalysts and solvents. Green earth and blue sky: Herein, we wish to disclose a simple bench top procedure for the synthesis of sulfonated core-shell magnetic nanoparticles (SMNPs) (Fe3O4@SiO2@PrSO3H) and discuss its performance as a very strong solid acid in the Pechmann condensation reaction.
- Esfahani, Farhad Kabiri,Zareyee, Daryoush,Yousefi, Reza
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p. 3333 - 3337
(2015/04/16)
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- Environmentally sustainable magnetic solid sulfonic acid: An efficient and reusable catalyst for the Pechmann reaction
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Abstract An environmentally benign sulfonic acid nanocomposite based on Fe3O4@SiO2 core-shell magnetic nanoparticles, Fe3O4@SiO2@Et-PhSO3H, was prepared and the acidity and utility of the catalyst were explored for the synthesis of a diverse range of coumarin derivatives under solvent-free conditions. The catalyst shows potential for scale up in the synthesis of coumarins with high purity and was easily separated by using an external magnet. The recovered catalyst was reused in seven cycles without any significant loss of activity.
- Mobaraki, Akbar,Yasham, Shahriar,Movassagh, Barahman
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supporting information
p. 1263 - 1268
(2015/06/02)
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- A solvent-free synthesis of coumarins using 1,3-disulfonic acid imidazolium hydrogen sulfate as a reusable and effective ionic liquid catalyst
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Abstract 1,3-Disulfonic acid imidazolium hydrogen sulfate has been used as an effective and reusable ionic liquid catalyst for the synthesis of coumarins from phenol derivatives with β-ketoesters via the Von Pechmann condensation under solvent-free conditions. This method consistently has the advantages of excellent yields, easy and quick isolation of the products, short reaction times, and green aspects by avoiding toxic catalysts and solvents. Further, the catalyst can be recovered and reused for four times without loss of activity.
- Shirini, Farhad,Yahyazadeh, Asieh,Mohammadi, Kamal
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p. 6207 - 6218
(2015/08/18)
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- An efficient synthesis of coumarin derivatives using a SBA-15 supported cobalt(II) nanocatalyst
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The catalytic performance of highly active cobalt(II) supported on mesoporous SBA-15 materials for the Pechmann reaction was investigated. SBA-15 supported cobalt(II) nanocatalyst was found to be efficient and easily recoverable in the Pechmann reaction of phenols and b-ketoesters to their corresponding coumarin derivatives under solvent-free conditions. The supported cobalt catalyst could be easily recovered after reaction completion and reused twelve times with an excellent durability and without any noticeable loss in activity.
- Rajabi, Fatemeh,Feiz, Afsaneh,Luque, Rafael
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p. 1621 - 1625
(2019/11/28)
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- Synthesis of substituted coumarins catalyzed by sawdust-SO3H. An efficient and environmentally benign solid acid catalyst under solvent-free conditions
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The sulfonated sawdust (SD-SO3H) was easily prepared by treatment of sawdust, a biomass waste material, with chlorosulfonic acid and characterized by elemental analysis, SEM and TGA. The bio-degradable solid acid catalyst has been applied to the Pechmann condensation reaction of phenols with β-ketoesters for the synthesis of coumarin derivatives under solvent-free conditions. This environmentally benign and inexpensive method has such advantages as simplicity in operation, high yields, low catalyst loading and short reaction time. The catalyst can be efficiently recycled with insignificant loss of activity.
- Tahanpesar,Sarami
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p. 2135 - 2140
(2015/10/29)
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- Synthesis and heterogeneous catalytic activity of covalently immobilized hexamine cation as a magnetically-recoverable nanocatalyst
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Functionalized magnetic core-shell nanoparticles Fe3O4-SiO2-HMTA are prepared by co-precipitation method and characterized by SEM, TEM, FT-IR, XRD, and VSM. The particles are spherical with an average size of approximately 48 nm. The catalytic activity of these nanoparticles was tested in solvent-free synthesis of coumarin derivatives. The catalyst was readily recycled by the use of an external magnetic field and can be reused four times without significant loss of activity or mass.
- Kangari, Sahar,Yavari, Issa,Maasoumi, Bakhshali
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p. 1771 - 1779
(2015/08/06)
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- Cholinium ionic liquids as cheap and reusable catalysts for the synthesis of coumarins via Pechmann reaction under solvent-free conditions
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A cheap cholinium ionic liquid N,N′-dimethylaminoethanol hydrosulfate ([N112OH][HSO4]) was found to be an efficient and reusable catalyst for the Pechmann condensation under solvent-free conditions. The coumarin products can be simply separated and the ionic liquid catalyst can be recycled and reused for at least six runs without noticeable decrease in the catalytic activity. The UV-vis studies suggested that the increase of the acidity and the introduction of a hydroxyl group to the cation benefit the existence of the keto tautomer of ethyl acetoacetate, which then leads to the excellent performance of [N112OH][HSO4].
- Zhang, Yuehua,Zhu, Anlian,Li, Qianqian,Li, Lingjun,Zhao, Yang,Wang, Jianji
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p. 22946 - 22950
(2014/06/24)
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- Diazabicyclo[2.2.2]octane stabilized on Fe3O4 as catalysts for synthesis of coumarin under solvent-free conditions
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Fe3O4-diazabicyclo[2.2.2]octane (Fe3O 4-DABCO) magnetic nanoparticles (MNPs) catalyst was readily prepared from inexpensive starting materials in aqueous media which catalyzed the synthesis of coumarin. FTIR spectroscopy, X-ray diffraction, transmission electron micrographs were employed to characterize the properties of the synthesized Fe3O4-DABCO MNPs. High catalytic activity and ease of recovery from the reaction mixture using external magnet, and several reuse times without significant losses in performance are additional eco-friendly attributes of this catalytic system.
- Nasseri, Mohammad Ali,Sadeghzadeh, Seyed Mohsen
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- CuFe2O4 nanoparticles: A magnetically recoverable and reusable catalyst for the synthesis of coumarins via pechmann reaction in water
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The synthesis of coumarins by hydroxyalkylation of phenols with ethyl acetoacetate (via Pechmann reaction) is attempted using magnetically separable and reusable CuFe2O4 nanoparticles in water. [Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications for the following free supplemental resource(s): Full experimental and spectral details.] Copyright
- Baghbanian, Seyed Meysam,Farhang, Maryam
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p. 697 - 706
(2014/01/17)
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- Role of basicity, calcinations, catalytic activity and recyclability of hydrotalcite in eco-friendly synthesis of coumarin derivatives
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An efficient and simple protocol is described for synthesis of coumarin derivatives using Mg-Al-CO3 and Ca-Al-CO3 hydrotalcite as an environmental friendly and reusable heterogeneous catalyst under solvent free conditions. The catalysts were characterized by Hammett titration, SEM and XRD data. Present study revealed that catalytic activity and basicity depend on compositions of hydrotalcite. The calcined hydrotalcite with an Mg/Al of 3:1 derived from calcinations at 750 K was found to be suitable catalyst that gives the highest basicity and the best catalytic activity for this reaction. Catalyst allows short reaction time, high catalytic activity, easy to work up and is reusable. Step economy, atom efficiency and solvent free conditions are some important salient features of this protocol.
- Sahu, Pramod K.,Sahu, Praveen K.,Agarwal, Dau D.
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p. 251 - 260
(2014/12/11)
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- Use of a highly efficient and recyclable solid-phase catalyst based on nanocrystalline titania for the pechmann condensation
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Nanocrystalline titania-based sulfonic acid was used as an efficient and reusable catalyst for the synthesis of coumarins. The clean, mild acidity condition, the quantitative yields of products, the short reaction time, and the low reaction temperature are attractive features of this method, making it suitable for heat- or acid-sensitive substrates, particularly in drug synthesis. In practice, this method affords an advantageous combination of satisfactory yields, easy product isolation and purification.
- Atghia, Seyyed Vahid,Beigbaghlou, Somayyeh Sarvi
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p. 1155 - 1159
(2015/02/05)
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- Synthesis of polyacrylonitrile fiber-supported poly(ammonium methanesulfonate)s as active and recyclable heterogeneous br?nsted acid catalysts
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A new polyacrylonitrile fiber-supported Br?nsted acid catalyst has been developed and verified to efficiently (high yield, 10 cycles) mediate Biginelli reactions in ethanol, Pechmann condensations in toluene, Friedel-Crafts alkylations of indoles in water and conversion of fructose in dimethyl sulfoxide (DMSO) and mixed-aqueous system.
- Shi, Xian-Lei,Xing, Xiaoli,Lin, Huikun,Zhang, Wenqin
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supporting information
p. 2349 - 2354
(2014/07/21)
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- Synthesis of coumarin derivatives using glutamic acid under solvent-free conditions
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An efficient,simple and one-pot protocol for synthesis of coumarin derivatives on the basis condensation reaction of phenols with ethyl acetoacetate employing glutamic acid as a novel catalyst is described.
- Sabetpoor, Setareh,Hatamjafari, Farhad
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p. 863 - 865
(2015/02/02)
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- Microwave assisted convenient one-pot synthesis of coumarin derivatives via Pechmann condensation catalyzed by FeF3 under solvent-free conditions and antimicrobial activities of the products
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A rapid and efficient solvent-free one-pot synthesis of coumarin derivatives by Pechmann condensation reactions of phenols with ethyl acetoacetate using FeF3 as a catalyst under microwave irradiation is described. This one-pot synthesis on a solid inorganic support provides the products in good yields. The newly synthesized compounds were systematically characterized by IR, 1H-NMR, 13C-NMR, MS and elemental CHN analyses. The proposed solvent-free microwave irradiation method using the environmentally friendly catalyst FeF3 offers the unique advantages of high yields, shorter reaction times, easy and quick isolation of the products, excellent chemoselectivity, and a one-pot, green synthesis. The products were screened for antimicrobial activity, and the results showed that the compounds reacted against all the tested bacteria.
- Vahabi, Vahid,Hatamjafari, Farhad
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p. 13093 - 13103
(2015/02/19)
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- Synthesis of the coumarins via pechmann method in the presence of environmentally friendly Y(NO3)3×6H2O
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Several substituted coumarins can be prepared in high yield and purity by direct reaction of β-keto esters and phenol derivatives in the presence of a catalytic amount Y(NO3)3×6H2O as Lewis acid and at ambient temperature under solvent-free conditions. Several substituted coumarins can be prepared in high yield and purity by direct reaction of β-keto esters and phenol derivatives in the presence of a catalytic amount Y(NO3)3×6H2O as Lewis acid and at ambient temperature under solvent-free conditions. This method that is based on Pechmann condensation is very easy and rapid reaction for the synthesis of coumarin derivatives. Copyright
- Karami, Bahador,Kiani, Mahtab
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p. 213 - 216
(2014/05/06)
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- FeCl3-catalysed ultrasonic-assisted, solvent-free synthesis of 4-substituted coumarins. A useful complement to the Pechmann reaction
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The catalytic activity of FeCl3 for the synthesis of a variety of 4-substituted coumarins using high energy techniques has been investigated. The ultrasonic-assisted conditions provide a useful complement to the Pechmann reaction, affording the coumarin derivatives in excellent yields, under solvent-free conditions, in short reaction times using an inexpensive, mild and benign Lewis acid catalyst.
- Prousis, Kyriakos C.,Avlonitis, Nicolaos,Heropoulos, Georgios A.,Calogeropoulou, Theodora
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p. 937 - 942
(2014/02/14)
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- Synthesis and nematicidal bioevaluation of substituted 2H-1-benzopyrane-2- ones and their carbamate derivatives against root-knot nematode (Meloidogyne javanica)
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Synthesis of 7-hydroxy-4,5-methyl/7-hydroxy-4-methyl/7,8-dihydroxy-4- methyl/6-chloro-7-hydroxy-4-methyl-2H-1-benzopyrane-2-ones (VI-IX) have been carried out by Pechmann reaction. The condensation of synthesized 2H-1-benzopyran-2-ones (VI-X) with phenyl isocyanate (XI) gave 4,5-methyl/4-methyl/4-methyl/6-chloro-4-methyl-2-oxo-2H-benzopyran-7yl/7,8-diyl/ 4-yl/phenyl carbamates (XIIXVI). The synthesized compounds were characterized on the basis of analytical and spectral data. All the compounds were evaluated for their nematicidal activity in vitro against second stage juveniles (J2) of root-knot nematode (Meloidogyne javanica).
- Kumari, Sumona,Singh, Rajvir,Kumar, Anil,Walia
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p. 3139 - 3143
(2014/07/22)
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- Ultrasound-assisted one-pot synthesis of substituted coumarins catalyzed by poly(4-vinylpyridinium) hydrogen sulfate as an efficient and reusable solid acid catalyst
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Poly(4-vinylpyridinium) hydrogen sulfate solid acid was found to be efficient catalyst for synthesis of substituted coumarins via Pechmann reaction using ultrasound irradiation at room temperature and neat condition in high yields with short reaction times. This methodology offers momentous improvements over various options for the synthesis of coumarins with regard to yield of products, simplicity in operation and green aspects by avoiding toxic catalysts and solvents. Further, the catalyst can be reused and recovered for several times.
- Khaligh, Nader Ghaffari
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p. 1062 - 1068
(2013/04/24)
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- A green, efficient and recyclable poly(4-vinylpyridine)-supported copper iodide catalyst for the synthesis of coumarin derivatives under solvent-free conditions
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Poly(4-vinylpyridine)-supported copper iodide is reported as a green, efficient and recyclable catalyst for the synthesis of coumarin derivatives by the Pechmann reaction under solvent-free conditions. This catalyst can be recovered by simple filtration and recycled up to eight consecutive runs without any loss of their efficiency.
- Albadi, Jalal,Shirini, Farhad,Abasi, Jafar,Armand, Nezam,Motaharizadeh, Tayebeh
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p. 407 - 411
(2013/07/05)
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- Succinimide-N-sulfonic acid catalyzed synthesis of bis(indolyl)methane and coumarin derivatives under mild conditions
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A mild and simple procedure is described for the synthesis of bis(indolyl)methane and coumarin derivatives using succinimide-N-sulfonic acid as an efficient, cheap, and reusable catalyst under mild conditions.
- Shirini, Farhad,Khaligh, Nader Ghaffari
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p. 1890 - 1896
(2013/11/19)
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- Introduction of poly(4-vinylpyridinium) perchlorate as a new, efficient, and versatile solid acid catalyst for one-pot synthesis of substituted coumarins under ultrasonic irradiation
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Poly(4-vinylpyridinium) perchlorate, is a supported, recyclable, eco-benign catalyst for synthesis of substituted coumarins via Pechmann reaction using ultrasound irradiation at room temperature and neat condition in high yields with short reaction times. The catalyst was studied by FT-IR, X-ray diffraction, scanning electron microscope, thermo-gravimetric and energy dispersion X-ray analyses. All the products were extensively characterized by 1H NMR, FT-IR, MS and melting point analyses. This methodology offers momentous improvements over various options for the synthesis of coumarins with regard to yield of products, simplicity in operation and green aspects by avoiding toxic catalysts and solvents. Further, the catalyst can be reused and recovered for several times without loss of activity.
- Khaligh, Nader Ghaffari,Shirini, Farhad
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p. 26 - 31,6
(2012/12/11)
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- Br?nsted-acidic imidazolium ionic liquid [bmim(SO 3H)][OTf]: A mild catalyst for highly efficient synthesis of coumarins
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The use of Br?nsted-acidic imidazolium ionic liquid [bmim(SO 3H)][OTf] as a catalyst for the high yielding synthesis of a wide variety of coumarins under mild conditions via Pechmann condensation has been demonstrated. This method is simple and has benefits from the easy way to isolate coumarins in good yields. In comparison with the classical Pechmann condensation, this new method consistently has the advantage of high yields and good purity.
- Haldorai, Yuvaraj,Kalkhambkar, Rajesh G.,Shim, Jae-Jin
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p. 9379 - 9383
(2013/11/19)
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