- CF3SOCl-promoted intramolecular cyclization of β-diketones: An efficient synthesis of flavones
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An efficient intramolecular cyclization reaction of β-diketones containing a phenyl group with an ortho-hydroxyl substituent was achieved. Using CF3SOCl as an additive, the reaction took place under transition-metal-free and mild conditions. A series of flavones were synthesized in moderate to excellent yields.
- Sun, Dong-Wei,Zhou, Yong-Yan,Jiang, Min,Nian, Tang,Liu, Jin-Tao
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- A novel one-pot synthesis of flavones
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In this paper, a one-pot facile route for the BiCl3/RuCl3-mediated synthesis of functionalized flavones is described, including: (i) intermolecularortho-acylation of substituted phenols with cinnamoyl chlorides, and (ii) intramolecular cyclodehydrogenation of the resultingo-hydroxychalcones. The reaction conditions are discussed herein.
- Chang, Meng-Yang,Tsai, Min-Chen,Lin, Chun-Yi
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p. 11655 - 11662
(2021/03/31)
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- Experimental and theoretical insights into the photophysical and electrochemical properties of flavone-based hydrazones
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A small library of flavone-based hydrazones has been designed, synthesized and characterized. In this context, thirteen flavone hydrazones (3a-3 m) were synthesized by the acid-catalyzed condensation of flavone with 2,4-dinitrophenylhydrazine (2,4-DNPH) and characterized by different spectral techniques (IR, UV–Vis, NMR and mass spectrometry). The electrochemical, photophysical and theoretical investigations of such type of compounds are hitherto unknown. The electrochemical behavior of these hydrazones at a platinum electrode has been analyzed by cyclic voltammetry (CV) and was investigated at 200, 100 and 40 mVs?1 in acetonitrile (CH3CN). These hydrazones showed a quasi-reversible redox reaction. The oxidation–reduction reactive sites of these derivatives were located via geometry optimization using density functional theory (DFT) at the B3LYP/3–21 g in the Guassian-09 level of theory. Moreover, the target compounds exhibited interesting fluorescent properties. Owing to their excellent photophysical and redox results, a detailed structure-property relationship was established to assess the substituents impact and their position on the physicochemical and electronic properties. All the experimental results were in accordance with the computational studies.
- Ahmed, Ishtiaq,Ahmed, Safeer,Ahmed, Saleh A.,Alsantali, Reem I.,Alsharif, Meshari A.,Altaf, Ataf Ali,Altass, Hatem M.,Jassas, Rabab. S.,Kausar, Samia,Mughal, Ehsan Ullah,Mumtaz, Amara,Naeem, Nafeesa,Obaid, Rami J.,Sadiq, Amina,Zafar, Muhammad Naveed
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- Flavone-based hydrazones as new tyrosinase inhibitors: Synthetic imines with emerging biological potential, SAR, molecular docking and drug-likeness studies
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Targeting tyrosinase (TYR), a key enzyme responsible for melanogenesis disorders, is a well-known approach utilized for the development of melanogenesis inhibitor. A variety of dermatological disorders and microbial skin infections can cause hyperpigmentation. Hence, exploring new scaffolds for the treatment of melanogenesis disease is an inspiring goal. In this context, a series of varyingly substituted flavone-based hydrazones have been designed, synthesized and characterized successfully. The present study describes the discovery of novel mushroom tyrosinase inhibitors (TIs) for treating hyperpigmentation. In due course, flavone scaffold has been incorporated into the novel chemotypes that exhibit in vitro inhibitory effects against mushroom tyrosinase for the purpose of discovering anti‐melanogenic agents. Biological investigations of prepared analogs herein demonstrated moderate to excellent activity against most of the fungal-bacterial strains and their activity is comparable to those of commercially available antibiotics i.e., Ciprofloxacin and Ketoconazole. Based on in vitro tyrosinase inhibitory assay, some compounds exhibited potent inhibition particularly, 3g (IC50 = 1.40 ± 0.16 μM), 3j (IC50 = 0.95 ± 0.07 μM), 3o (IC50 = 1.13 ± 0.11 μM), and 3q (IC50 = 1.01 ± 0.1 μM) showed best inhibition i.e., 0.7, 0.5, 0.6 and 0.5 folds, respectively, than kojic acid (IC50 = 1.79 ± 0.6 μM). Lineweaver-Burk plots demonstrated that the most potential derivative 3j tyrosinase inhibition proceeds via non-competitive pathway and the Michaelis-Menton constant (Km) value is 0.0265. Molecular modeling was performed for all tested analogs (3a–3q) using a model of mushroom tyrosinase to find crucial binding modes liable for inhibitory activity. The SARs were preliminarily examined, and the docking study revealed that analogs 3j, 3o and 3p had a strong binding association to tyrosinase (2Y9X). Furthermore, a drug-likeness study was employed and confirmed the favorable activity of the new analogs as a new anti-tyrosinase agent.
- Ahmed, Saleh A.,Ali, Anser,Alsantali, Reem I.,Alsharif, Meshari A.,Alsimaree, Abdulrahman A.,Altass, Hatem M.,Asghar, Basim H.,Jassas, Rabab. S.,Javed, Qamar,Javid, Asif,Moussa, Ziad,Mughal, Ehsan Ullah,Naeem, Nafeesa,Sadiq, Amina,Sumrra, Sajjad Hussain,Zafar, Muhammad Naveed
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- Robust alkyl-bridged bis(N-heterocyclic carbene)palladium(II) complexes anchored on Merrifield's resin as active catalysts for the selective synthesis of flavones and alkynones
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Highly active and efficient propylene-bridged bis(N-heterocyclic carbene)palladium(II) complexes covalently anchored on Merrifield's resin were synthesized and characterized using various physical and spectroscopic techniques. The two anchored Pd(II) complexes consist of the system: Merrifield's resin-linker-bis(NHC)Pd(II), the linkers being benzyl and benzyl-O-(CH2)3 for (Pd-NHC1@M) and (Pd-NHC2@M), respectively. The short linker anchored bis-benzimidazolium ligand precursor (PBBI-1@M) was synthesized via direct carbon–nitrogen alkylation of a propylene-bridged bis(benzimidazole) (PBBI-1) by Merrifield's resin chlorobenzyl group. The longer linker anchored bis-benzimidazolium ligand precursor (PBBI-2@M) was obtained in a two-step reaction involving first alkylation of (PBBI-1) with 3-chloro-1-propanol followed by a nucleophilic substitution at Merrifield's resin chlorobenzyl group. Both supported ligand precursors (PBBI-1@M and PBBI-2@M) reacted with palladium acetate to produce the two heterogeneous catalysts (Pd-NHC1@M) and (Pd-NHC2@M). 13C NMR palladation shift of the benzimidazole N–C–N (C2) carbon was found very similar in both the liquid NMR spectra of the homogeneous complexes and the CP/MASS spectra of the corresponding covalently anchored complexes. The catalytic activity, stability, and the recycling ability of the supported catalysts have been investigated in the carbonylative Sonogashira coupling reactions of aryl iodides with aryl alkynes and alkyl alkynes and also in the cyclocarbonylative Sonogashira coupling reactions of aryl iodides with aryl alkynes via one pot reactions. The longer linker catalyst Pd-NHC2@M demonstrated excellent catalytic activity, stability, and very high recycling ability in the two carbonylative coupling reactions. These systems exhibit the hypothesized thermodynamic stability offered by the chelate effect in addition to the strong sigma donor ability of a bis(NHC) ligand system generating electron-rich palladium centers that favor the oxidative addition step of the aryl halide.
- Mansour, Waseem,Fettouhi, Mohammed,Saleem, Qasim,El Ali, Bassam
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- Divergent synthesis of flavones and flavanones from 2′-hydroxydihydrochalconesviapalladium(ii)-catalyzed oxidative cyclization
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Divergent and versatile synthetic routes to flavones and flavanonesviaefficient Pd(ii) catalysis are disclosed. These Pd(ii) catalyses expediently provide a variety of flavones and flavanones from 2′-hydroxydihydrochalcones as common intermediates, depending on oxidants and additives,viadiscriminate oxidative cyclization sequences involving dehydrogenation, respectively, in a highly atom-economic manner.
- Son, Seung Hwan,Cho, Yang Yil,Yoo, Hyung-Seok,Lee, Soo Jin,Kim, Young Min,Jang, Hyu Jeong,Kim, Dong Hwan,Shin, Jeong-Won,Kim, Nam-Jung
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p. 14000 - 14006
(2021/04/22)
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- Design, synthesis and biological evaluation of substituted flavones and aurones as potential anti-influenza agents
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We designed a series of substituted flavones and aurones as non-competitive H1N1 neuraminidase (NA) inhibitors and anti-influenza agents. The molecular docking studies showed that the designed flavones and aurones occupied 150-cavity and 430-cavity of H1N1-NA. We then synthesized these compounds and evaluated these for cytotoxicity, reduction in H1N1 virus yield, H1N1-NA inhibition and kinetics of inhibition. The virus yield reduction assay and H1N1-NA inhibition assay demonstrated that the compound 1f (4-methoxyflavone) had the lowest EC50 of 9.36 nM and IC50 of 8.74 μM respectively. Moreover, kinetic studies illustrated that compounds 1f and 2f had non-competitive inhibition mechanism.
- Chintakrindi, Anand S.,Gohil, Devanshi J.,Chowdhary, Abhay S.,Kanyalkar, Meena A.
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supporting information
(2019/11/29)
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- Facile synthesis of 6-phenyl-6h-chromeno [4, 3-b] quinoline derivatives using nahso4&at;sio2 re-usable catalyst and their antibacterial activity study correlated by molecular docking studies
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Background: Heterocyclic compounds containing heteroatoms (O, N and S) as part of five or six-membered cyclic moieties exhibited various potential applications, such as pharmaceutical drugs, agrochemical products and organic materials. Among many known heterocyclic moieties, quinoline and its derivatives are one of the privileged scaffolds found in many natural products. In general, quinoline derivatives could be prepared by utilizing ortho-substituted anilines and carbonyl compounds containing a reactive α-methylene group of well-known reaction routes like Friedlander synthesis, Niemantowski synthesis and Pfitzinger synthesis. Moreover, polysubstituted quinolones and their derivatives also had shown considerable interest in the fields of organic and pharmaceutical chemistry in recent years. Objectives: The main objective of our research work is towards the design and synthesis of divergent biological-oriented, proactive analogues with potential pharmacological value inspired by the anti-tubercular activity of 2-phenylquinoline analogues. In this study, we have been interested in the design and synthesis of bioactive, 2, 4-diphenyl, 8-arylated quinoline analogues. Methods: 6-phenyl-6h-chromeno [4, 3-b] quinoline derivatives were synthesized from 4-chloro-2phenyl-2H-chromene-3-carbaldehyde and various substituted aromatic anilines as starting materials using sodium bisulfate embedded SiO2 re-usable catalyst. All these fifteen new compound structures confirmed by spectral data1H &13C NMR, Mass, CHN analysis etc. Furthermore, all these new compounds antibacterial activity strains recorded using the paper disc method. The compound molecular structures were designed using molecular docking study by utilizing the crystallographic parameters of S. Areus Murb protein. Results: A series of fifteen new quinoline derivatives synthesized in moderate to good yields using sodium bisulfate embedded SiO2 re-usable catalyst. The molecular structures of these newly synthesized compounds elucidated by the combination of spectral data along with the elemental analysis. These compounds antibacterial activity study have shown moderate to good activity against, Escherichia coli (Gram-negative) and Staphylococcus aureus (gram-positive) organisms. These antibacterial activity results were also a very good correlation with molecular docking studies. Conclusion: In this study, fifteen new quinoline derivatives synthesized and structures confirmed by spectral data. In fact, all the compounds have shown moderate to good antibacterial activity. In general, the compounds containing the electron donor group at R1 position (R1 = OMe) and the acceptor group at R2 positions (R2 = F or Cl) had shown good antibacterial activity. These antibacterial activity results were also a very good correlation with molecular docking studies showing strong binding energies with the highest value being,-12.45 Kcal mol-1 with S. aureus MurB receptor.
- Anuradha, Vejendla,Basaveswara Rao, Mandava Venkata,Prashanth, Jyothi,Rao, Koya Prabhakara,Subramanyam, Madala,Suman, Kancharla
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p. 929 - 938
(2020/07/10)
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- Rh-Catalyzed aldehydic C-H alkynylation and annulation
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Novel Rh-catalyzed aldehydic C-H bond alkynylation and annulation for the in situ synthesis of chromones and aurones are described. It involves the sequential aldehyde C-H bond alkynylation of salicylaldehyde with in situ generated 1-bromoalkyne from 1,1-
- Ramakrishna, Boddu S.,Rao, Maddali L. N.
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p. 1402 - 1411
(2020/03/03)
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- Method for synthesizing 2-aryl benzopyrone flavonoid derivatives
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The invention relates to a method for synthesizing 2-aryl benzopyrone flavonoid derivatives, and relates to a method for synthesizing a compound, the method for synthesizing 2-aryl benzopyrone flavonoid derivatives is suitable for the synthesis of 2-aryl benzopyrone flavonoid derivatives containing different substituents. The method aims to solve the technical problems of low yield, long reactionperiod, and complicated post-treatment and high operation difficulty of the existing synthesis method of the ketone flavonoid derivative. The method comprises the following steps of: 1, preparing beta-propanedione compounds; 2, preparing flavonoid compound 2-aryl benzopyranones. The method completes esterification and rearrangement in one step, which is simple and practical, reduces intermediate links of reaction, saves separation and purification of intermediate products, improves utilization rate of raw materials, reduces reaction temperature, shortens reaction time under microwave radiation, reduces solvent consumption, the post-treatment is relatively simple, the yield is relatively high and no by-products exist, and can also react in the presence of a small amount of water, the reaction is easy to operate, and the method is suitable for industrial production. The method belongs to the technical field of compound synthesis.
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- Microwave assisted efficient synthesis of flavone using ZnO nanoparticles as promoter under solvent-free conditions
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A simple and highly efficient protocol for synthesis of flavones from 1-(2-hydroxyphenyl)-3-aryl-1,3-propanediones in presence of ZnO nanoparticles as a promoter in thermal as well as microwave irradiation under solvent-free conditions have been demonstrated. The catalyst is inexpensive, stable, can be easily recycled/reused for several cycles with consistent activity and observed almost same yield confirming the stability of the catalyst. It is believed that the present approach will become an alternative route for the conventional reactions. Because in this protocol, yield is quite high, short reaction time, simple work up, catalyst can be recycled as well as it is free of any hazardous by-products formation during workup.
- Unde, Pradip J.,Thorat, Nitin M.,Patil, Limbraj R.
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p. 1133 - 1136
(2019/04/05)
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- Temperature-Controlled Stereodivergent Synthesis of 2,2′-Biflavanones Promoted by Samarium Diiodide
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In this work, the first example of a radical stereodivergent reaction directed towards the stereoselective synthesis of both (R*,R*)- and (R*,S*)-2,2′-biflavanones promoted by samarium diiodide is reported. Control experiments showed that the selectivity of this reaction was exclusively controlled by the temperature. It was possible to generate a variety of 2,2′-biflavanones bearing different substitution patterns at the aromatic ring in good-to-quantitative yields, being both stereoisomers of the desired compounds obtained with total or high control of selectivity. A mechanism that explains both the generation of the corresponding 2,2′-biflavanones and the selectivity is also discussed. The structure and stereochemistry determination of each isomer was unequivocally elucidated by single-crystal X-ray diffraction experiments.
- Soto, Martín,Soengas, Raquel G.,Silva, Artur M. S.,Gotor-Fernández, Vicente,Rodríguez-Solla, Humberto
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supporting information
p. 13104 - 13108
(2019/10/21)
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- Water-mediated phosphorylative cyclodehydrogenation: An efficient preparation of flavones and flavanones
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A new synthetic strategy utilizing POCl3-water for the conversion of 2′-hydroxychalcones to flavanones and flavones has been developed. The reagent efficiently promoted one-pot conversion of 2′-hydroxychalcones to flavones through flavanones involving cyclization and oxidative dehydrogenation. By changing the stoichiometery of the reagents, the reaction can be tuned to generate either flavanone or flavone. The developed protocol was found to be applicable for a variety of 2′-hydroxychalcones.
- Vimal, Manorama,Pathak, Uma,Halve, Anand Kumar
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supporting information
p. 2805 - 2814
(2019/08/12)
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- Synthesis of flavonoid derivatives as antimalarial agents
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Some flavonoid derivatives were synthesized for the evaluation of their antimalarial activity. The antimalarial activity of synthesized flavonoid derivatives was screened against Plasmodium falciparum parasite. To validate antimalarial activity, in silico drug-likeness and docking study was also carried out using the P. falciparum falcipain-2 enzyme. Results of antimalarial activity reveal the antimalarial potential of synthesized flavonoids. Drug-likeness and molecular docking study confirms the biopotential and antimalarial effectiveness of flavonoid derivatives as novel falcipain-2 inhibitors. The flavonoid scaffold reported herein may be useful toward further development of novel antimalarial lead molecules.
- Chetia, Dipak,Kalita, Jahnabi,Patowary, Pooja,Rudrapal, Mithun
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- Rhodium(III)-catalyzed one-pot synthesis of flavonoids from salicylaldehydes and sulfoxonium ylides
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Rh(III)-catalyzed C–H activation of salicylaldehyde followed by an insertion reaction with sulfoxonium ylides and cyclization is applied to the synthesis of flavonoids. This one-pot strategy exhibits good functional group tolerance and gives flavones in moderate-to-good yields.
- Cheng, Kang,Chen, Jinkang,Jin, Licheng,Zhou, Jian,Jiang, Xinpeng,Yu, Chuanming
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p. 392 - 398
(2019/09/03)
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- An efficient tandem synthesis of chromones from: O -bromoaryl ynones and benzaldehyde oxime
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An effective transition-metal-free strategy was developed for the preparation of chromones from o-bromoaryl ynones and benzaldehyde oxime through sequential C-O bond formation. This cyclization reaction could well tolerate a wide range of functional groups, and the corresponding chromones were given in moderate to excellent yields. Mechanistically, benzaldehyde oxime as a hydroxide source and 1,3-diketone derivatives as reaction intermediates were involved in this transformation.
- Zhang, Jing-Wen,Yang, Wan-Wan,Chen, Lu-Lu,Chen, Pei,Wang, Yan-Bo,Chen, Dan-Yun
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p. 7461 - 7467
(2019/08/20)
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- Regioselective hydrodehalogenation of aromatic α-and β-halo carbonyl compounds by cui in isopropanol
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An operationally efficient and regioselective hydrodehalogenation methodology of aromatic α-and β-halo carbonyl compounds has been developed using CuI in isopropanol at 90 °C under basic condition. The catalytic system effectively dehalogenates chloride, bromide, and iodide groups and af-forded high yield (up to 97 %) as carbonyl compounds. The methodology is environmentally friendly and demonstrates excellent tolerance to a broad range of electronically rich and poor substituents.
- Parveen, Iram,Khan, Danish,Ahmed, Naseem
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p. 759 - 764
(2019/01/09)
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- Aminoalkyl-substituted flavonoids: synthesis, cholinesterase inhibition, β-amyloid aggregation, and neuroprotective study
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In this manuscript, 17 aminoalkyl-substituted flavonoid derivatives were synthesized and their anticholinesterase, anti-beta-amyloid (Aβ) aggregation and neuroprotective activities were evaluated. The synthesized compounds were prepared through four-step reaction, started from the reaction between 2-hydroxyacetophenone and 4-methoxy benzaldehyde. Among the final compounds, 6j displayed the best anti-butyrylcholinesterase activity (IC50 = 0.335 μM). Moreover, compound 6i significantly protected PC12 neurons against H2O2-induced cell death. This compound could also inhibit acetylcholinesterase and self-induced Aβ peptide aggregation by 51.3% and 49.2%, respectively. The results indicated that compound 6i could be considered as a lead compound towards the discovery of disease-modifying drugs for Alzheimer’s disease (AD) therapy.
- Faraji, Laleh,Nadri, Hamid,Moradi, Alireza,Bukhari, Syed Nasir Abbas,Pakseresht, Bahar,Moghadam, Farshad Homayouni,Moghimi, Setareh,Abdollahi, Mohammad,Khoobi, Mehdi,Foroumadi, Alireza
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p. 974 - 983
(2019/06/04)
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- A 2 - aryl flavone preparation method
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The invention discloses a 2 - aryl flavone preparation method, including: in the silver catalyst and under the action of the oxidizing agent, ortho-hydroxy aryl formyl formic acid and aryl alkynoic ring reaction in a solvent, after the reaction is finished after treatment to obtain the 2 - aryl flavone. The method of this invention easily obtained and cheap agents, mild reaction conditions, reaction functional group compatibility is good, cheap catalyst, the catalytic system is simple.
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Paragraph 0034; 0035; 0036; 0037
(2018/07/15)
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- An Efficient One-Pot Synthesis and Anticancer Activity of 4'-Substituted Flavonoids
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A number of 4'-substituted (R = H, Me, Cl, F) flavone derivatives is synthesized from 2-hydroxyacetophenones using the modified Baker–Venkataraman reaction. Compound [3-(4-fluorobenzoyl)-5- hydroxy-4'-fluoroflavone] was synthesized for the first time with the yield of 12%. Antiproliferative assays indicate that the synthesized flavones with F substituent at the 4' position demonstrate higher activity than the other flavone derivatives, particularly against HeLa and MCF-7 with the IC50 9.5 and 2.7 μM, respectively.
- Wang,Liu,Zhang
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p. 1036 - 1041
(2018/07/06)
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- Design, synthesis and biological evaluation of 2-Phenyl-4H-chromen-4-one derivatives as polyfunctional compounds against Alzheimer’s disease
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Polyfunctional compounds comprise a novel class of therapeutic agents for the treatment of multi-factorial diseases. A series of 2-Phenyl-4H-chromen-4-one and its derivatives (5a–n) were designed, synthesized, and evaluated for their poly-functionality against acetylcholinestrase (AChE) and advanced glycation end products (AGEs) formation inhibitors against Alzheimer’s disease (AD). The screening results showed that most of them exhibited a significant ability to inhibit AChE AGEs formation with additional radical scavenging activity. Especially, 5m, 5b, and 5j displayed the greatest ability to inhibit AChE (IC50 = 8.0, 8.2, and 11.8 nM, respectively) and AGEs formation (IC50 = 55, 79, and 54 μM, respectively) with good antioxidant activity. Molecular docking studies explored the detailed interaction pattern with active, peripheral, and mid-gorge sites of AChE. These compounds, exhibiting such multiple pharmacological activities, can be further taken a lead for the development of potent drugs for the treatment of Alzheimer’s disease.
- Singh, Manjinder,Kaur, Maninder,Vyas, Bhawna,Silakari, Om
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p. 520 - 530
(2017/10/09)
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- Rational design for multicolor flavone-based fluorophores with aggregation-induced emission enhancement characteristics and applications in mitochondria-imaging
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Fluorophores with aggregation-induced emission enhancement (AIEE) properties have attracted more attention in recent years. In order to realise more valuable applications, the different kinds of AIEE molecules are in serious need of further development. Therefore, a novel flavone-based AIEE system derived from restriction of intramolecular rotation (RIR) was designed and synthesized in this work. The results revealed that six of the compounds showed typical AIEE characteristics, with fluorescence emissions from purple, blue, cyan to green, tunable by changing substituent groups. This flavone-based AIEE system has never been reported before. The AIEE characteristics were investigated by optical spectroscopy, fluorescence photographs, scanning electron microscopy (SEM), fluorescence quantum yields (φF) and fluorescence lifetime in the CH3OH/H2O mixed solution. Moreover, benefiting from the simple structures and small molecular weight, they could permeate cells faster than current high-molecular-weight AIEE molecules. Furthermore, to examine possible biomedical applications, fluorescence imaging in living A549 lung cells and cell viabilities were examined, and the results displayed that these fluorophores showed good cellular uptake and low cytotoxicity within the experimental concentration range. In addition, these AIEE compounds possessed excellent specificity for mitochondrial targeting and mitochondrial morphological change tracking, besides, they displayed superior photostability, which indicated they are potential candidates for mitochondrial imaging.
- Liu, Liyan,Lei, Yaohui,Zhang, Jianhui,Li, Na,Zhang, Fan,Wang, Huaqiao,He, Feng
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- Synthesis and biological evaluation of Complex I inhibitor R419 and its derivatives as anticancer agents in HepG2 cells
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In this study, Complex I inhibitor R419 was firstly revealed to have significant anticancer activity against HepG2 cells (IC50 = 5.2 ± 0.9 μM). Based on this finding, a series of R419 derivatives were synthesized and biologically evaluated. As results, 9 derivatives were found to have obvious anticancer activity. Among them, H20 exhibited the most potent activity (IC50 = 2.8 ± 0.4 μM). Mechanism study revealed that H20 caused severe depletion of cellular ATP, dose-dependently activated AMPK, decreased Bcl-2/Bax ratio and induced necrotic cell death. Most importantly, H20 displayed definite inhibitory activity against Complex I.
- Huang, Yaping,Sun, Geng,Wang, Pengfei,Shi, Rui,Zhang, Yanchun,Wen, Xiaoan,Sun, Hongbin,Chen, Caiping
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supporting information
p. 2957 - 2960
(2018/07/21)
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- Synthesis of 3,5-diarylisoxazole derivatives and evaluation of in vitro trypanocidal activity
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Chagas disease is included in the neglected tropical diseases list and is endemic to 21 Latin American countries. The two drugs currently available for treating Chagas disease are nifurtimox and benznidazole and both result in many significant side effects. The study describes the synthesis and biological evaluation of 3,5-disubstituted isoxazoles. Isoxazoles were obtained by reaction of flavones and hydroxylamine and either alkylated at the free hydroxyl group and/or nitrated at the isoxazole ring. These compounds were evaluated for their in vitro anti-Trypanosoma cruzi activity against trypomastigote and amastigote forms of the parasite in T. cruzi-infected cell lineages. Benznidazole was used as a reference compound for the in vitro assay and mammalian L929 cells were employed to evaluate cytotoxicity. A majority of the compounds tested were very active and the most active isoxazole against amastigote and trypomastigotes of T. cruzi was slightly more potent than the current medicine benznidazole.
- De Souza, Aline A. N.,Xavier, Viviane F.,Coelho, Gleicekelly S.,Sales Junior, Policarpo A.,Romanha, Alvaro J.,Murta, Silvane M. F.,Carneiro, Claudia M.,Taylor, Jason G.
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p. 269 - 277
(2017/12/08)
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- Silver-catalyzed Double Decarboxylative Radical Alkynylation/Annulation of Arylpropiolic Acids with α-keto Acids: Access to Ynones and Flavones under Mild Conditions
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Ynones are privileged building blocks in various organic syntheses of heterocyclic derivatives due to their multifunctional nature, and flavones are an important class of natural products with a wide range of biological activities. We describe the catalytic double decarboxylative alkynylation of arylpropiolic acids with α-keto acids. With Ag(I)/persulfate as the catalysis system, the valuable ynones bearing various substituents could be easily obtained. The introduction of hydroxyl substituent on ortho-site of α-keto acids make this strategy further applicable to the construction of flavone derivatives via heteroannulation in moderate to good yields with a similar silver-catalyzed system. The reactions proceed under relatively mild reaction conditions and tolerate a wide variety of functional groups. Control experiments indicated that both the reactions undergo radical processes. (Figure presented.).
- Meng, Mengting,Wang, Guofang,Yang, Liangfeng,Cheng, Kai,Qi, Chenze
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p. 1218 - 1231
(2018/02/16)
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- Divergent synthesis of flavones and aurones via base-controlled regioselective palladium catalyzed carbonylative cyclization
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A regioselective approach for construction of 5-membered and 6-membered flavonoid is established by Pd catalyzed carbonylative cyclization of 2-iodophenol with terminal alkynes using different amine bases under mild reaction condition. The catalytic experiments found that piperazine preferentially accelerate 6-endo cyclization, and triethylamine mediated Pd catalyzed 5-exo cyclization. Under optimized reaction condition, Pd catalyzed carbonylative protocol successfully applied for the diverse structures of 39 examples in good to excellent yield and regioselectivity.
- Xu, Shan,Sun, Huaming,Zhuang, Mengyuan,Zheng, Shaohua,Jian, Yajun,Zhang, Weiqiang,Gao, Ziwei
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p. 264 - 270
(2018/05/04)
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- Nickel catalysed carbonylative Sonogashira reaction for the synthesis of diarylalkynones and 2-substituted flavones
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The nickel catalyzed, palladium/phosphine free carbonylative Sonogashira reaction of terminal alkynes with substituted aryl and heteroaryl iodides is described. This protocol provides mild and robust conditions to synthesize a variety of substituted aryl α,β-alkynyl ketones and flavones in good to excellent isolated yields. This methodology tolerates several functional groups such as electron donating (methyl, isopropyl, tert-butyl, methoxy) as well as electron withdrawing (trifluoromethyl, nitro, esters, nitrile) groups on the terminal alkynes and iodides.
- Charugandla, Renuka,Vangala, Markandeya Sarma,Chidara, Sridhar,Korupolu, Raghu Babu
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supporting information
p. 3283 - 3287
(2018/07/25)
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- Synthesis of a series of chalcones and related flavones and evaluation of their antibacterial and antifungal activities
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Background: A series of chalcones and flavones were synthesized from 2’-hydroxyacetophenone and substituted aromatic aldehydes via Simmons-Schmidt condensation followed by oxidative cyclization. Methods: Characterization of the obtained structures was established on the basis of their spectroscopic data. The synthesized compounds were screened for their antimicrobial activities against five bacterial strains (Citrobacter freundii, Staphylococcus aureus, Listeria monocytogenes, Salmonella braenderup, Escherichia coli.) and two fungal strains (Candida albicans, Candida krusei). Results: The in vitro bioassay results indicated that some target compounds displayed moderate (4d, 4e) to high (4a) antifungal activity against the pathogenic fungi C. albicans and C. krusei. Conclusion: For the antibacterial activity, only products 3d and 4d showed a weak antibacterial activity. These compounds can lead to the design of new drugs with specific antifungal activity.
- Benouda, Hind,Bouchal, Btissam,Challioui, Allal,Oulmidi, Abdelkader,Harit, Tarik,Malek, Fouad,Riahi, Abdelkhalek,Bellaoui, Mohammed,Bouammali, Boufelja
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- Base-free nickel-catalysed decarbonylative Suzuki–Miyaura coupling of acid fluorides
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The Suzuki–Miyaura cross-coupling of organoboron nucleophiles with aryl halide electrophiles is one of the most widely used carbon–carbon bond-forming reactions in organic and medicinal chemistry1,2. A key challenge associated with these transformations is that they generally require the addition of an exogenous base, the role of which is to enable transmetallation between the organoboron nucleophile and the metal catalyst3. This requirement limits the substrate scope of the reaction because the added base promotes competitive decomposition of many organoboron substrates3–5. As such, considerable research has focused on strategies for mitigating base-mediated side reactions6–12. Previous efforts have primarily focused either on designing strategically masked organoboron reagents (to slow base-mediated decomposition)6–8 or on developing highly active palladium precatalysts (to accelerate cross-coupling relative to base-mediated decomposition pathways)10–12. An attractive alternative approach involves identifying combinations of catalyst and electrophile that enable Suzuki–Miyaura-type reactions to proceed without an exogenous base12–14. Here we use this approach to develop a nickel-catalysed coupling of aryl boronic acids with acid fluorides15–17, which are formed in situ from readily available carboxylic acids18–22. This combination of catalyst and electrophile enables a mechanistic manifold in which a ‘transmetallation-active’ aryl nickel fluoride intermediate is generated directly in the catalytic cycle13,16. As such, this transformation does not require an exogenous base and is applicable to a wide range of base-sensitive boronic acids and biologically active carboxylic acids.
- Malapit, Christian A.,Bour, James R.,Brigham, Conor E.,Sanford, Melanie S.
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p. 100 - 104
(2018/11/25)
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- Novel and Efficient Access to Flavones under Mild Conditions: Aqueous HI-Mediated Cascade Cyclization/Oxidative Radical Reaction of 2-Propynolphenols
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Herein we disclose a metal-free and efficient method for the direct conversion of 2-propynolphenols to biologically important flavones using aqueous HI as the promoter. This transformation was proved via 4-iodo-2H-chromenes intermediate, which was simultaneously conversed to corresponding flavones by a Csp2?I bond cleavage and a C–O bond formation under air.
- Song, Xian-Rong,Li, Ren,Yang, Tao,Chen, Xi,Ding, Haixin,Xiao, Qiang,Liang, Yong-Min
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supporting information
p. 5548 - 5552
(2018/10/24)
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- Method for synthesizing flavonoid derivatives
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A method for synthesizing flavonoid derivatives comprises: using o-propargyl alcohol phenol as a raw material, adding an organic solvent to fully dissolve the raw material at room temperature, then adding hydriodic acid, reacting at 40 to 60 DEG C for 1 to 2 hours, after the reaction is finished, spin-drying a reaction solution, separating the reaction solution by silica gel column chromatographyto obtain a target effluent, allowing the effluent to stand in a test tube for 1 to 48 hours, and then converting the effluent into flavonoid compounds, wherein the molar ratio of o-propargyl alcoholphenol to hydroiodic acid is 1:1.5 to 2; the organic solvent is a C1-C4 halogenated hydrocarbon or acetonitrile or nitromethane. The method has the characteristics of mild reaction condition, simple operation, simple and easy raw material, high reaction yield, and the like, and is a good synthesis method with good popularization and application prospect.
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Paragraph 0018-0019
(2019/01/08)
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- One-pot Synthesis of Aurones through Oxidation-cyclization Tandem Reaction Catalyzed by Copper Nanoparticles Catalyst
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Aurones were synthesized through an oxidation-cyclization tandem reaction of 2-(1- hydroxyprop-2-ynyl)phenols catalyzed by copper nanoparticles (Cu NPs) with bipyridine as the ligand. In the reaction, oxygen worked as a green and mild oxidant to give the best results. Cu NPs were dually activated by bipyridine ligand and water, and showed highly efficient catalytic activities to the oxygen oxidation and the cylization to give aurones and flavonoids.
- Yu, Min,Liu, Guangxiang,Han, Chengyan,Zhu, Li,Yao, Xiaoquan
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- Carbonylative Sonogashira annulation sequence: One-pot synthesis of 4-quinolone and 4H-chromen-4-one derivatives
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Carbonylative Sonogashira annulation sequence for one pot synthesis of 4-quinolone and 4H-chromen-4-one has been developed in presence of Pd-NHC catalyst. Substituted 2-iodoaniline and 2-iodophenol independently underwent in the carbonylative Sonogashira
- Ghosh, Prasanjit,Nandi, Aritra Kumar,Das, Sajal
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p. 2025 - 2029
(2018/04/25)
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- Pd/C: An efficient and reusable catalyst for the synthesis of flavones via carbonylation of aryl halides
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This work describes an efficient and mild approach for the synthesis of flavones via catalytic carbonylation of aryl halides with 2-hydroxyacetophenone using the commercial Pd/C as an efficient, heterogeneous and recyclable catalyst. Under balloon pressure of CO, 0.6?mol% Pd/C is sufficient for moderate yields of flavones for the carbonylation of aryl iodides under phosphine-free conditions and aryl bromides in the presence of phosphine ligand. The catalyst is easily separable and shows significant recyclability. Moreover, the reaction mechanism was discussed, and a possible mechanism that contains two different cyclisation pathways was proposed.
- Lei, Yizhu,Li, Zhi,Wan, Yali,Zhou, Xiao-Yu,Li, Guangxing,Shi, Kaiyi
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- One-Pot Allan–Robinson/Friedl?nder Route to Chromen-/Quinolin-4-ones through the Domino Acetylative Cyclisation of 2-Hydroxy-/2-Aminobenzaldehydes
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The domino synthesis of 2-phenyl-4H-chromen-4-ones and quinolin-4-ones through acetylation of 2-hydroxy-/2-aminobenzaldehydes with α-haloketones followed by intramolecular oxa-/azaheterocyclisation is reported. This method represents a new extension of the Allan–Robinson and Friedl?nder reactions, and uses N-heterocyclic-carbene catalysis to construct the target molecules in good to excellent yields: 86–95 % for the chromen-4-ones, and 83–96 % for the quinolin-4-ones. This approach has the advantages of operational simplicity, ambient reaction conditions, and no by-product formation.
- Rai, Vijai K.,Verma, Fooleswar,Sahu, Ganeshwar P.,Singh, Manorama,Rai, Ankita
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p. 537 - 544
(2018/02/09)
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- One Pot Synthesis of γ-Benzopyranones via Iron-Catalyzed Aerobic Oxidation and Subsequent 4-Dimethylaminopyridine Catalyzed 6-endo Cyclization
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One-pot synthesis of γ-benzopyranones was realized in decent yields and excellent regioselectivities via iron-catalyzed aerobic oxidation and 4-dimethylaminopyridine-catalyzed cyclization of related propargylic alcohols. Derivatizations to aromatic substituted γ-benzopyranones and synthesis of naturally occurring 3′,4′-dimethoxyflavone have also been realized. (Figure presented.).
- Zhai, Di,Chen, Lingzhu,Jia, Minqiang,Ma, Shengming
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p. 153 - 160
(2017/11/23)
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- The five carbonyl iron as CO release source preparation benzopyranone compounds (by machine translation)
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The invention discloses a five-carbonyl iron as CO release source preparation benzopyranone compound of the method, the method to acetic acid palladium are the catalyst, piperazine is alkali, five carbonyl iron as CO release source, so that the 2 - iodo phenol compound with a terminal alkyne under mild condition coupled reactions, generating benzopyranone compounds. The invention has simple operation, mild reaction conditions, less catalyst levels, low source amount used CO release, toxicity is relatively small, low cost, wide applicability of the substrate, the target substance high yield, natural product can be widely used for the preparation of the benzopyranone compound. (by machine translation)
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Paragraph 0014-0018
(2017/07/06)
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- Silica-gel-supported Ce(SO4)2·4H2O-mediated cyclization of 2′-amino and 2′-hydroxychalcones under solvent-free conditions
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A simple, efficient, and environmentally friendly approach for the synthesis of flavones, aza-flavones, and aza-flavanones from corresponding 2′-hydroxy or 2′-aminochalcones has been developed. The reactions are successfully conducted in presence of silica-gel-supported Ce(SO4)2·4H2O under solvent-free conditions.
- Liu, Ruihuan,Zhang, Yan,Xu, Kangping,Tan, Guishan
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supporting information
p. 1 - 9
(2016/12/30)
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- Unified Approach to (Thio)chromenones via One-Pot Friedel-Crafts Acylation/Cyclization: Distinctive Mechanistic Pathways of β-Chlorovinyl Ketones
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A facile synthetic method to chromenones and thiochromenones has been developed using a one-pot Friedel-Crafts acylation of alkynes with suitably substituted benzoyl chlorides. This unified approach to (thio)chromenones is readily applicable to aryl- and alkylalkynes where the stereochemically well-defined β-chlorovinyl ketone intermediates undergo distinctively different cyclization pathways. The ready availability of both starting materials, alkynes and benzoyl chlorides, coupled with the experimental simplicity makes the current synthetic method to (thio)chromenones fast, efficient, and practical.
- Kim, Hun Young,Song, Eunsun,Oh, Kyungsoo
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supporting information
p. 312 - 315
(2017/04/21)
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- A transition-metal-free fast track to flavones and 3-arylcoumarins
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A highly regioselective and transition-metal free one-pot arylation of chromenones with arylboronic acids has been achieved employing K2S2O8. The procedure consists of a sequence of some reactions including an arylation/decarboxylation cascade and proceeds well in aqueous media to afford biologically interesting flavones and 3-arylcoumarins. This method exhibited excellent selectivity and functional group tolerance under mild conditions. The reaction also showed perfect efficacy for the preparation of styryl coumarins.
- Golshani, Mostafa,Khoobi, Mehdi,Jalalimanesh, Nafiseh,Jafarpour, Farnaz,Ariafard, Alireza
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supporting information
p. 10676 - 10679
(2017/10/06)
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- Synthesis of 4H-Chromen-4-one Derivatives by Intramolecular Palladium-Catalyzed Acylation of Alkenyl Bromides with Aldehydes
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The palladium-catalyzed intramolecular acylation of alkenyl bromides and aldehydes was developed for an efficient synthesis of 4H-chromen-4-ones. With Pd(PPh3)4/Xphos as the catalyst and K2CO3 as the base, this protocol was applied to synthesize a small library of diversely functionalized flavonoids in moderate to good yields in 1,4-dioxane.
- Yue, Yixia,Peng, Jinsong,Wang, Deqiang,Bian, Yunyun,Sun, Peng,Chen, Chunxia
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p. 5481 - 5486
(2017/05/24)
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- Guanidino-graphene catalysed synthesis of flavones via Aldol-Michael-oxidation
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Guanidino-graphene has been synthesized by the reaction of bromoamine with reduced graphene oxide and characterized by FT-IR, Raman, TGA, powder XRD, TEM, SEM, and zeta potential. It is a cheap, heterogeneous and environmentally benign solid base catalyst used for cascade Aldol-Michael-oxidation in the synthesis of chalcone, flavonoids.
- Mishra, Sweta,Arora, Smriti,Nagpal, Ritika,Chauhan, Shive Murat Singh
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p. 2525 - 2530
(2017/03/09)
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- Pd catalyzed couplings of “superactive esters” and terminal alkynes: Application to flavones and γ-benzopyranones construction
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Lewis base, N-methylmorpholine (NMM) accelerated Pd-catalyzed Sonogashira coupling of steric hindered super active esters, 1a–1e, and terminal alkynes. This approach provided an efficient synthetic protocol for a broad array of acylated o-alkynoylphenols compounds, 3a–3e, under moderate conditions. The mechanistic study clearly demonstrated that NNM stabilized the catalytic palladium species, and accelerated the leaving of triazine moiety during the catalytic cycle of the cross-coupling reactions. In addition, piperazine was found to efficiently catalyze the 6-endo cyclization of acylated o-alkynoylphenols, which achieved the diversity oriented synthesis of γ-benzopyranones, 4aa–4eg, with 93–99% yields.
- Yang, Dandan,Wang, Zhenhua,Wang, Xiu,Sun, Huaming,Xie, Zunyuan,Fan, Juan,Zhang, Guofang,Zhang, Weiqiang,Gao, Ziwei
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- Identification and structure activity relationship of novel flavone derivatives that inhibit the production of nitric oxide and PGE2 in LPS-induced RAW 264.7 cells
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In an effort to identify novel anti-inflammatory compounds, a series of flavone derivatives were synthesized and biologically evaluated for their inhibitory effects on the production of nitric oxide (NO) and prostaglandin E2 (PGE2), representative pro-inflammatory mediators, in LPS-induced RAW 264.7 cells. Their structure-activity relationship was also investigated. In particular, we found that compound 3g displayed more potent inhibitory activities on PGE2 production, similar inhibitory activities on NO production and less weak cytotoxicity than luteolin, a natural flavone known as a potent anti-inflammatory agent.
- An, Ji-Young,Lee, Hwi-Ho,Shin, Ji-Sun,Yoo, Hyung-Seok,Park, Jong Seon,Son, Seung Hwan,Kim, Sang Won,Yu, Jihyun,Lee, Jun,Lee, Kyung-Tae,Kim, Nam-Jung
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p. 2613 - 2616
(2017/05/10)
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- The acetoxy protection of the benzopyranone compound preparation acetylenic ketone method
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The invention discloses a method for preparing benzopyrone compounds through adopting acetoxy protected alkynyl ketone. The benzopyrone compounds are generated through a direct ring closure reaction of acetoxy protected alkynyl ketone at room temperature with piperazine as a catalyst. The method has the advantages of simple operation, no need of ligands, low price and small amount of the catalyst, stability of the catalyst to air and water, mild reaction conditions, short reaction time, low cost, high atom economy, extensive substrate applicability, and simple post-treatment and high yield of target products, and can be widely used to prepare natural products benzopyrone compounds.
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Page/Page column 0015-0018
(2017/08/19)
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- An efficient oxidative conversion of 2-aryl-2H-chromenes to the corresponding flavones by tert-butylhydroperoxide and copper bromide
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A simple and efficient method has been developed for the facile oxidation of chromenes to the corresponding flavones by tert-butylhydroperoxide (TBHP) in the presence of copper(II) bromide catalyst in toluene at 80 °C in a very short time. The reaction demonstrates excellent reactivity, functional group tolerance, and good to excellent yields without using conventional strong oxidizing agents.
- Banerjee, Dipanwita,Kayal, Utpal,Maiti, Gourhari
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supporting information
p. 1667 - 1671
(2016/04/04)
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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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- Mild and efficient organocatalytic method for the synthesis of flavones
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A convenient and efficient organocatalytic procedure for the selective cyclization of 1,3-diketones to give aromatic substituted 4H-chromen-4-ones under mild reaction conditions using N-triflyl phosphoramide is described. Application of the described conditions is presented in a formal synthesis of (S)-flavanone.
- Stanek, Filip,Stodulski, Maciej
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supporting information
p. 3841 - 3843
(2016/08/02)
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- Ultrasonic-assisted synthesis of flavones by oxidative cyclization of 2′-hydroxychalcones using iodine monochloride
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This paper presents an efficient methodology for the synthesis of flavones via the oxidative cyclization of 2′-hydroxychalcones in the presence of iodine monochloride with DMSO under ultrasound irradiation. Ultrasonic irradiation enhances the cyclization reaction and leads to reduced reaction time at lower reaction temperatures while generating flavones with high yields.
- Lahyani, Achraf,Trabelsi, Mahmoud
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p. 626 - 630
(2016/02/23)
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- Scaffold-hopping of bioactive flavonoids: Discovery of aryl-pyridopyrimidinones as potent anticancer agents that inhibit catalytic role of topoisomerase IIα
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A strategy of scaffold-hopping of bioactive natural products, flavones and isoflavones, leading to target-based discovery of potent anticancer agents has been reported for the first time. Scaffold-hopped flavones, 2-aryl-4H-pyrido[1,2-a]pyrimidin-4-ones and the scaffold-hopped isoflavones, 3-aryl-pyrido[1,2-a]pyrimidin-4-ones were synthesized via Pd-catalyzed activation–arylation methods. Most of the compounds were found to exhibit pronounced human topoisomerase IIα (hTopoIIα) inhibitory activities and several compounds were found to be more potent than etoposide (a hTopoIIα-inhibiting anticancer drug). These classes of compounds were found to be hTopoIIα-selective catalytic inhibitors while not interfering with topoisomerase I and interacted with DNA plausibly in groove domain. Cytotoxicities against various cancer cells, low toxicity in normal cells, and apoptotic effects were observed. Interestingly, compared to parent flavones/isoflavones, their scaffold-hopped analogs bearing alike functionalities showed significant/enhanced hTopoIIα-inhibitory and cytotoxic properties, indicating the importance of a natural product-based scaffold-hopping strategy in the drug discovery.
- Priyadarshani, Garima,Amrutkar, Suyog,Nayak, Anmada,Banerjee, Uttam C.,Kundu, Chanakya N.,Guchhait, Sankar K.
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