- A 'one pot' synthesis of 2-aryl-4H-1-benzopyran-4-ones under coupled microwave phase transfer catalysis (PTC) and ultrasonic irradiation PTC
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(Chemical Equation Presented) A 'one pot' synthesis of 2-aryl-4H-1- benzopyran-4-ones (3a-3f) is being reported. A mixture of o-hydroxyacetophenone, aroyl chloride, powdered n-tetrabutylammonium hydrogensulphate (n-TBAHSO 4) and potassium hydroxide (KOH) were either irradiated by microwaves or sonicated in an ultrasonic cleaning bath to afford flavones directly. On the contrary, conventional liquid-liquid Phase Transfer Catalysis (PTC) using benzene as organic phase and aqueous KOH as the second phase afforded first β-diketones in accordance with Baker-Venkataraman synthesis which upon cyclization by p-toluenesulphonic acid (p-TSA) gave desired flavones in the next step. PTC coupled with microwaves or ultrasound show enhanced yields, the clean reaction conditions require less time, and have easier workup protocol. All synthesized compounds were characterized by their Proton Magnetic Resonance (PMR), IR, FAB Mass and elemental analyses.
- Pathak, Vijai N.,Gupta, Ragini,Varshney, Bindu
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- Silica-PCL5: An efficient and reusable catalyst for cyclodehydration of 1, 3-diketones to flavones
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Silica-PCl5 was employed as efficient solid acid catalyst for conversion of 1, 3-diketones to flavones under solventfree condition. Reaction is simple, efficient with easy work up and the catalyst is recyclable.
- Vimal, Manorama,Pathak, Uma,Mathur, Sweta,Pandey, Lokesh Kumar,Suryanarayana
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- A facile synthesis of flavones catalysed by gallium(III) triflate
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Ga(OTf)3 was explored as a novel catalyst for the cyclisation of 1-(2-hydroxyphenyl)-3-aryl-1,3-propanediones in nitromethane to flavones with excellent yields.
- Jin, Can,He, Fei,Wu, Huayue,Chen, Jiuxi,Su, Weike
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- Gold Nanoparticles Supported on a Layered Double Hydroxide as Efficient Catalysts for the One-Pot Synthesis of Flavones
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Flavones are a class of natural products with diverse biological activities and have frequently been synthesized by step-by-step procedures using stoichiometric amounts of reagents. Herein, a catalytic one-pot procedure for the synthesis of flavone and its derivatives is developed. In the presence of gold nanoparticles supported on a Mg-Al layered double hydroxide (Au/LDH), various kinds of flavones can be synthesized starting from 2′-hydroxyacetophenones and benzaldehydes (or benzyl alcohols). The present one-pot procedure consists of a sequence of several reactions, and Au/LDH can catalyze all these different types of reactions. The catalysis is shown to be truly heterogeneous, and Au/LDH can be readily recovered and reused. Go for gold: In the presence of gold nanoparticles supported on a Mg-Al layered double hydroxide (Au/LDH), various flavones were obtained from the corresponding 2′-hydroxyacetophenones and benzaldehydes (or benzyl alcohols). All three (four) steps of this one-pot process are catalyzed by Au/LDH in a truly heterogeneous fashion.
- Yatabe, Takafumi,Jin, Xiongjie,Yamaguchi, Kazuya,Mizuno, Noritaka
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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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- 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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- Cyclization of 2'-hydroxychalcones to flavones using ammonium iodide as an iodine source - An eco-friendly approach
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Ammonium iodide on exposure to air decomposes to ammonia and iodine. The in situ generated iodine was used for the cyclization of 2'-hydroxychalcones to the corresponding flavones under solvent-free conditions in good to excellent yields. This method could serve as an attractive alternative to the existing methods for synthesis of flavones and the use of toxic molecular iodine is avoided. Copyright
- Kulkarni, Pramod S.,Kondhare, Dasharath D.,Varala, Ravi,Zubaidha, Pudukulathan K.
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- The Direct Preparation of Flavones from 2'-Hydroxychalcones Using Disulfides
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Flavone was obtained by a reaction of 2'-hydroxychalcone with disulfides in good yield.Among several disulfides, diphenyl disulfide gave the best result.Under the same conditions, some flavones were obtained from the corresponding 2'-hydroxychalcones in satisfactory yields.
- Hoshino, Yukio,Oohinata, Toshinori,Takeno, Noboru
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- Syntheses of flavones via the iodine-mediated oxidative cyclization of 1,3-diphenylprop-2-en-1-ones
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The syntheses of flavones from 1,3-diphenylporp-2-ene-1-ones are described. When 1,3-diphenylprop-2-en-1-ones were heated with iodine in triethylene glycol, oxidative cyclization underwent to obtain flavones in good yields.
- Miyake, Hideyoshi,Takizawa, Eizo,Sasaki, Mitsuru
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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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- A Facile Preparation of Flavones Using Nonaqueous Cation-Exchange Resin
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Flavone was prepared from 1-(2-hydroxyphenyl)-3-phenyl-1,3-propanedione by using nonaqueous cation exchange resin in a nearly quantitative yield.Of several reaction media, isopropyl alcohol gave the best result.Eight substituted flavones were also synthesized from the corresponding diketones in satisfactory yields.
- Hoshino, Yukio,Takeno, Noboru
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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.
- Alsantali, Reem?I.,Mughal, Ehsan?Ullah,Naeem, Nafeesa,Alsharif, Meshari?A.,Sadiq, Amina,Ali, Anser,Jassas, Rabab.?S.,Javed, Qamar,Javid, Asif,Sumrra, Sajjad Hussain,Alsimaree, Abdulrahman?A.,Zafar, Muhammad?Naveed,Asghar, Basim?H.,Altass, Hatem?M.,Moussa, Ziad,Ahmed, Saleh?A.
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- 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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- 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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- 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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- 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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- 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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p. 13104 - 13108
(2019/10/21)
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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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- 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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- 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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- Iodine-mediated direct synthesis of 3-iodoflavones
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Molecular iodine has been used for the regioselective, one pot, direct synthesis of 3-iodoflavones from 2′-allyloxy chalcones, 2′-hydroxy chalcones and flavones. Allyl deprotection, cyclization dehydrogenation and α-iodination of 2′-allyloxychalcones has been achieved in a single step to offer 3-iodoflavones.
- Patil, Avinash M.,Kamble, Dayanand A.,Lokhande, Pradeep D.
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p. 1299 - 1307
(2018/04/05)
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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 0016-0017
(2019/01/08)
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- Synthesis, antiproliferative and pro-apoptotic effects of nitrostyrenes and related compounds in Burkitt’s lymphoma
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Background: Cancers of the lymphatic cells (lymphomas) account for approximately 12% of malignant diseases worldwide. The nitrostyrene scaffold is identified as a lead target structure for the development of particularly effective compounds targeting Burkitt’s lymphoma (BL). Objectives: The aims of the curent study were to synthesise a panel of nitrostyrene compounds and to evaluate their activity in Burkitt’s lymphoma (BL). Methods: A panel of structurally varied compounds were designed and synthesised using Henry Knoevenagel condensation reactions. Single crystal X-Ray analysis confirmed the E configuration for six examples of these novel structures. A number of nitrostyrene-related compounds were also investigated including 1,3-bis(aryl)-2-nitropropenes together with heterocyclic scaffolds containing the nitrovinyl pharmacophore such as 3-nitro-2-phenyl-2H-chromenes. The antiproliferative activities of the compounds were evaluated using the BL cell lines EBV- MUTU-1 and EBV+ DG-75 (chemoresistant) to establish preliminary structure-activity relationships. Results: Lead compounds with optimized nitrostyrene scaffolds and 3-nitro-2-phenyl-2Hchromene structures were successfully established with typical IC50 values of 0.45 μM and 0.47 μM in MUTU-1 cells and 1.41 μM and 1.92 μM, respectively, in DG-75 cells. The mechanism of cell death was identified as apoptotic and the lead compound was found to elicit comparable apoptotic effects to Taxol in Burkitt’s lymphoma cell lines MUTU-1 and DG-75. Conclusion: This class of pharmaceutically active compounds with potential for the treatment of Burkitt’s lymphoma suggest a potential role for nitrostyrene based agents in chemotherapy.
- Byrne, Andrew J.,Bright, Sandra A.,Fayne, Darren,McKeown, James P.,McCabe, Thomas,Twamley, Brendan,Williams, Clive,Meegan, Mary J.
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p. 181 - 199
(2018/03/13)
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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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supporting information
p. 153 - 160
(2017/11/23)
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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 0055-0058
(2017/08/19)
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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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- 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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- 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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- Synthesis and antiviral activity of 2-aryl-4H-chromen-4-one derivatives against Chikungunya virus
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A series of nineteen 2-aryl-4H-chromen-4-one derivatives 2a-2s were synthesized and evaluated for their antiviral activity against Chikungunya virus (LR2006-OPY1) in Vero cell culture by CPE reduction assay. Three compounds 2a, 2b and 2g, were found to be active at concentration of (IC50) 0.44 μM, 0.45 μM and 2.02 μM, respectively. Compounds having heterocyclic ring 2a and 2b at the 2nd position of the chromenone were found to be potent inhibitor of ChikV. Cytotoxicity studies were performed using Vero cell culture, compounds 2a and 2b exhibited SI of ≥100. Molecular docking simulation has been carried out to understand the possible mechanism of action.
- Badavath, Vishnu N.,Jadav, Surender S.,Pastorino, Boris,De Lamballerie, Xavier,Sinha, Barij N.,Jayaprakash, Venkatesan
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p. 1019 - 1024
(2016/11/25)
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- Highly efficient synthesis of flavones: Via Pd/C-catalyzed cyclocarbonylation of 2-iodophenol with terminal acetylenes
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A highly efficient and selective Pd/C-catalyzed ligand-free cyclocarbonylation reaction for the synthesis of flavones has been developed. Various flavone derivatives were isolated in excellent yields with excellent functional group tolerances. Additionally, catalyst reuse experiments were performed successfully as well.
- Zhu, Fengxiang,Li, Yahui,Wang, Zechao,Wu, Xiao-Feng
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p. 2905 - 2909
(2016/05/24)
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- Aldose reductase inhibitors for diabetic complications: Receptor induced atom-based 3D-QSAR analysis, synthesis and biological evaluation
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Herein, atom-based 3D-QSAR analysis was performed using receptor-guided alignment of 46 flavonoid inhibitors of aldose reductase (ALR2) enzyme. 3D-QSAR models were generated in PHASE programme, and the best model corresponding to PLS factor four (QSAR4), was selected based on different statistical parameters (i.e., Rtrain2, 0.96; Qtest2 0.81; SD, 0.26). The contour plots of different structural properties generated from the selected model were utilized for the designing of five new congener molecules. These designed molecules were duly synthesized, and evaluated for their in vitro ALR2 inhibitory activity that resulted in the micromolar (IC50 22 μM) activity of all molecules. Thus, the newly designed molecules having ALR inhibitory potential could be employed for the management of diabetic complications.
- Vyas, Bhawna,Singh, Manjinder,Kaur, Maninder,Bahia, Malkeet Singh,Jaggi, Amteshwar Singh,Silakari, Om,Singh, Baldev
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supporting information
p. 59 - 71
(2015/05/05)
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- Synthesis and anti-trypanosoma cruzi activity of diaryldiazepines
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Chagas disease is a so-called "neglected disease" and endemic to Latin America. Nifurtimox and benznidazole are drugs that have considerable efficacy in the treatment of the acute phase of the disease but cause many significant side effects. Furthermore, in the Chronic Phase its efficiency is reduced and their therapeutic effectiveness is dependent on the type of T. cruzi strain. For this reason, the present work aims to drive basic research towards the discovery of new chemical entities to treat Chagas disease. Differently substituted 5,7-diaryl-2,3-dihydro-1,4-diazepines were synthesized by cyclocondensation of substituted flavones with ethylenediamine and tested as anti-Trypanosoma cruzi candidates. Epimastigotes of the Y strain from T. cruzi were used in this study and the number of parasites was determined in a Neubauer chamber. The most potent diaryldiazepine that reduced epimastigote proliferation exhibited an IC50 value of 0.25 μM, which is significantly more active than benznidazole.
- Menezes, Jlio Csar L.,Vaz, Luana Beatriz A.,De Vieira, Paula Melo Abreu,Fonseca, Ktia Da Silva,Carneiro, Cludia Martins,Taylor, Jason G.
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- Monoamine oxidase inhibitory activity of 2-aryl-4H-chromen-4-ones
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A series of twenty 2-aryl-4H-chromen-4-one (flavones) derivatives (3a-3s) were synthesized and tested for hMAO inhibitory activity. Fifteen compounds (3a, 3c, 3e-3h, 3j-3p, 3r, 3s) were found to be selective towards MAO-B, while 3d was selective towards MAO-A, and 3b, 3i and 3q were non-selective. Experimental Selectivity Index for MAO-B ranges from 2.0 (3g, 3p) to 30.0 (3j). Compound 3j, which is carrying 3,4-di-OMeC6H3 groups at R position on the molecule, was found to be potent MAO-B inhibitor amongst the fifteen with Ki value for MAO-B of 0.16 ± 0.01 lM comparable to that of standard drug, Selegiline (Ki for MAO-B is 0.16 ± 0.01 μM). Compound 3j also appeared as the most selective MAO-B inhibitor according to its best selectivity index (30.0), which is comparable to that of Selegiline (SIMAO-B = 35.0). Molecular docking and molecular dynamics simulation studies were carried out using Autodock-4.0 and Amber12 to understand the molecular level interaction and energy relation of MAO isoforms with selective inhibitors (3d and 3j). Simulation results are in good agreement with the experimental results. Leads identified may further be explored to develop potent isoform specific inhibitors of MAO.
- Nayak, Badavath Vishnu,Ciftci-Yabanoglu,Bhakat, Soumendranath,Timiri, Ajay Kumar,Sinha, Barij N.,Ucar,Soliman, Mahmoud E. S.,Jayaprakash, Venkatesan
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- A versatile approach to flavones via a one-pot Pd(II)-catalyzed dehydrogenation/oxidative boron-Heck coupling sequence of chromanones
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A variety of flavones were expediently synthesized from readily accessible chromanones via a one-pot sequence involving Pd(ii)-catalyzed dehydrogenation and oxidative boron-Heck coupling with arylboronic acid pinacol esters. In particular, the use of arylboronic acid pinacol esters was found to significantly improve the yield of the reaction.
- Lee, Jun,Yu, Jihyun,Son, Seung Hwan,Heo, Jinyuk,Kim, Taelim,An, Ji-Young,Inn, Kyung-Soo,Kim, Nam-Jung
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p. 777 - 784
(2016/01/12)
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- Pd(OAc)2/S=PPh3 accelerated activation of gem-dichloroalkenes for the construction of 3-arylchromones
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The Pd-catalyzed regioselective intramolecular nucleophilic substitution of gem-dichloroalkene derivatives with salicylaldehydes leading to the synthesis of 3-arylchromones has been developed. Pd(OAc)2/S=PPh3 could activate gem-dichloroalkenes and undergo nucleophilic substitution by salicylaldehydes with the aid of a base.
- Liu, Jianming,Song, Weiwei,Yue, Yuanyuan,Liu, Ren,Yi, Hong,Zhuo, Kelei,Lei, Aiwen
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supporting information
p. 17576 - 17579
(2015/12/08)
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- SAR studies of o-hydroxychalcones and their cyclized analogs and study them as novel inhibitors of cathepsin B and cathepsin H
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Cathepsins have emerged as a potential target for anti-cancer drug development. In the present study, we have synthesized three structurally related series of flavanoids i.e., 2′-hydroxychalcones, flavanones and flavones and assayed in vitro to study their inhibitory potency against cathepsin B and H, promising drug candidate for cancer therapy. Enzyme kinetics studies were carried out in presence of these compounds after preliminary proteolytic studies on endogenous protein substrates. SAR studies suggested that open chain flavanoids were better inhibitors as compared to their cyclized analogs. The most potent inhibitors among the three series were nitro substituted compounds 1g, 2g and 3g with Ki values of ~6.18 × 10-8 M, 4.8 × 10-7 M and 7.85 × 10-7 M for cathepsin B and Ki values of ~2.8 × 10-7 M, 31.8 × 10-6 M and 33.7 × 10 -6 M for cathepsin H, respectively. The relationship between chalcone, flavanones and flavone structures interpreted by docking studies on cathepsin B and H also provided useful insights.
- Raghav,Garg
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- Monoamine oxidase inhibitory activity of 2-aryl-4H-chromen-4-ones
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A series of twenty 2-aryl-4H-chromen-4-one (flavones) derivatives (3a-3s) were synthesized and tested for hMAO inhibitory activity. Fifteen compounds (3a, 3c, 3e-3h, 3j-3p, 3r, 3s) were found to be selective towards MAO-B, while 3d was selective towards MAO-A, and 3b, 3i and 3q were non-selective. Experimental Selectivity Index for MAO-B ranges from 2.0 (3g, 3p) to 30.0 (3j). Compound 3j, which is carrying 3,4-di-OMeC6H3 groups at R position on the molecule, was found to be potent MAO-B inhibitor amongst the fifteen with Ki value for MAO-B of 0.16 ± 0.01 μM comparable to that of standard drug, Selegiline (Ki for MAO-B is 0.16 ± 0.01 μM). Compound 3j also appeared as the most selective MAO-B inhibitor according to its best selectivity index (30.0), which is comparable to that of Selegiline (SIMAO-B = 35.0). Molecular docking and molecular dynamics simulation studies were carried out using Autodock-4.0 and Amber12 to understand the molecular level interaction and energy relation of MAO isoforms with selective inhibitors (3d and 3j). Simulation results are in good agreement with the experimental results. Leads identified may further be explored to develop potent isoform specific inhibitors of MAO.
- Badavath, Vishnu Nayak,Ciftci-Yabanoglu,Bhakat, Soumendranath,Timiri, Ajay Kumar,Sinha, Barij N.,Ucar,Soliman, Mahmoud E.S.,Jayaprakash, Venkatesan
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- Pyrrolidine and iodine catalyzed domino aldol-Michael-dehydrogenative synthesis of flavones
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A one pot synthesis of flavones is established from 2′- hydroxyacetophenones and substituted aromatic aldehydes. The method uses domino aldol-Michael-oxidation reaction catalyzed by pyrrolidine as a base and iodine as an oxidant in dimethyl sulfoxide.
- Naik, Mayuri M.,Tilve, Santosh G.,Kamat, Vijayendra P.
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p. 3340 - 3343
(2014/06/09)
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- Synthesis of B-ring substituted flavones and evaluation of their antitumor and antioxidant activities
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A series of flavones, substituted at the ring B, were synthesized using either Claisen-Schimdt Condensation or Baker-Venkataraman rearrangement. The synthesized compounds were tested for in vitro cytotoxic activity by sulforhodamine B assay against three cell lines of different origin, viz. HepG2, MCF-7, and MOLT-4. The compounds were also tested for a possible antioxidant activity by determination of inhibition of lipid peroxidation. Quercetin was taken as a standard for antioxidant activity. Compound 1c showed the highest cytotoxic activity against MCF-7 (GI50 0.1 μM) and MOLT-4 (GI50 0.1 μM) cell lines and was comparable to adriamycin, the standard used. Compounds 1b, 1g, and 1h also showed promising activity against MCF-7 and MOLT-4 cell lines. In the absence of a hydroxyl group, one or more methoxy groups present on the B-ring (compounds 1c-1e) were major determinants of inhibition of lipid peroxidation.
- Joshi, Akshada J.,Gadhwal, Manoj K.,Joshi, Urmila J.,D'Mello, Priscilla,Sinha, Ragini,Govil, Girjesh
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p. 4293 - 4299
(2013/09/02)
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- Sodium perborate tetrahydrate-mediated transformations of 2′-hydroxychalcones to flavanones, flavones, and 3′, 5′-diiodoflavone under mild, environmentally friendly conditions
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Sodium perborate tetrahydrate has been utilized as a nucleophilic catalyst for facile conversion of 2′-hydroxychalcones to flavanones in warm aqueous acetonitrile, and then these chalcones, upon oxidative cyclization in warm acetic acid with an excess of the same reagent, afforded flavones in acceptable yields. One-pot synthesis of 3′,5′-diiodoflavone has been accomplished by diacetoxyiodobenzene-catalyzed iodination of 2′-hydroxychalcone with tetra-n-butylammonium iodide in acetic acid in the presence of sodium perborate as a terminal oxidant.
- Ganguly, Nemai C.,Chandra, Sumanta,Barik, Sujoy Kumar
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p. 1351 - 1361
(2013/05/09)
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- An efficient synthesis of 3-bromoflavones under solvent free conditions using grinding technique
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Selective bromination of 1-(2-hydroxyphenyl)-3-phenylpropane- 1,3-diones has been carried out with ammonium bromide and ammonium persulphate at room temperature using grinding technique under solvent free conditions to give 2-bromo derivatives which on cyclodehydration with p-toluenesulphonic acid under grinding conditions give 3-bromoflavones. Also, flavones on bromination using above mentioned conditions give 3-bromoflavones directly.
- Jakhar, Komal,Makrandi
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experimental part
p. 770 - 773
(2012/06/30)
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- Synthesis and biological activities of some flavones
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Chalcones are synthesized by a base catalyzed Claisen Schmidt condensation reaction and then treated with dimethylsulphoxide in presence of iodine to get flavones. The synthesized compounds were evaluated for their antibacterial activity against Escherichia coilt P. aeruginosa, S. epidermidis and B. subtilis. All the flavones showed moderate to good activity. The structures of these compounds were confirmed by IR, UV, 1H NMR, Mass and elemental analysis.
- Sawant,Gill,Nirwan
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- Synthesis and biological activities of some flavones
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Chalcones are synthesized by a base catalyzed Claisen Schmidt condensation reaction and then treated with dimethylsulphoxide in presence of iodine to get flavones. The synthesized compounds were evaluated for their antibacterial activity against Escherichia coli, P. aeruginosa, S. epidermidis and B. subtilis. All the flavones showed moderate to good activity. The structures of these compounds were confirmed by IR, UV, 1H NMR, Mass and elemental analysis.
- Sawant,Gill,Nirwan
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p. 297 - 300
(2013/09/24)
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- Palladium-catalyzed carbonylation reaction of aryl bromides with 2-hydroxyacetophenones to form flavones
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Flavone of the month: A general and efficient method for the palladium-catalyzed carbonylative synthesis of flavones has been developed (see scheme). Starting from aryl bromides and 2-hydroxyacetophenones, the corresponding flavones have been isolated in good yields. Copyright
- Wu, Xiao-Feng,Neumann, Helfried,Beller, Matthias
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supporting information
p. 12595 - 12598
(2012/11/07)
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- Synthetic approach to flavanones and flavones via ligand-free palladium(ii)-catalyzed conjugate addition of arylboronic acids to chromones
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The remarkable catalytic effects of Fe(OTf)3 in the context of the Pd(ii)-catalyzed conjugate addition of arylboronic acids to chromones were observed to yield a variety of flavanones under mild conditions. The addition of catalytic amounts of DDQ and KNO2 to the reactions exclusively yielded flavone analogs. The reaction scope for the transformation was fairly broad, affording good yields of a wide range of flavanones and flavones, which are privileged structures in many biologically active compounds.
- Kim, Donghee,Ham, Kyungrok,Hong, Sungwoo
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experimental part
p. 7305 - 7312
(2012/09/22)
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- K2CO3-catalyzed synthesis of chromones and 4-quinolones through the cleavage of aromatic C-O bonds
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Phenol-derived electrophiles are favorable substrates because phenols are naturally abundant or can be readily prepared from other aromatic compounds. However, the cleavage of aromatic C-O bonds is a great challenge because of their high energy. K2CO3-catalyzed intramolecular cyclization of 1-(2-alkoxyphenyl)-3-akylpropane-1,3-dione and 3-(alkylimino)-1-(2-methoxyphenyl)-2-methylpropan-1-one derivatives via the selective cleavage of aromatic C-O bonds is reported. The corresponding chromone and 4-quinolone derivatives were obtained in reasonable yields.
- Zhao, Jie,Zhao, Yufen,Fu, Hua
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supporting information; experimental part
p. 2710 - 2713
(2012/07/16)
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- A novel route to synthesis of flavones from salicylaldehyde and acetophenone derivatives
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Convenient, facile, and alternate synthesis of medicinally important flavones is reported. The 2-hydroxychalcones derived from condensation between acetophenones and salicylaldehyde, underwent oxidative cyclization on heating in the presence of catalytic iodine, generating diversified flavones under solvent-free conditions. Eleven compounds have been synthesized in good to excellent yields and their mechanism of formation is described.
- Sashidhara, Koneni V.,Kumar, Manoj,Kumar, Abdhesh
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p. 2355 - 2359
(2012/07/14)
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- Preparation of thioflavones via thiophosphoryl chloride mediated cyclodehydration and thionation of 1-(2-hydroxyphenyl)-3-arylpropane-1,3-diones
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A simple and convenient one-pot strategy for the preparation of thioflavones from 1,3-diketones is described. Cyclodehydration of a range of β-diketones and thionation of the resulting flavones was achieved using thiophosphoryl chloride (PSCl3) which serves as both a catalyst and thionating agent. Georg Thieme Verlag Stuttgart · New York.
- Vimal, Manorama,Pathak, Uma,Pandey, Lokesh Kumar,Suryanarayana, Malladi V. S.
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experimental part
p. 30 - 32
(2011/02/26)
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