- 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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- 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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- Green and efficient synthesis of flavones and chromones using heteropolyacids as catalyst in glycerol
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Organic solvents are required to carry out most organic transformations, which cause environmental pollution because of their low volatility. Glycerol, a side product obtained from biodiesel production, has emerged as a friendly solvent due to its advantageous properties. In this paper, an efficient procedure for the synthesis of flavones and chromones, using heteropolyacids as recyclable catalyst and glycerol as the solvent, is presented. The use of heteropolyacids as catalysts allows for excellent yields, easy separation and recovery, low environmental impact, and low cost. Glycerol can also be readily recovered and used over again. In addition, the presented method provides other advantages such as the low formation of waste and the replacement of corrosive mineral acids.
- Migliorero, María Belén Colombo,Palermo, Valeria,Durango, Edwin Alexis Alarcón,Holguín, Aída Luz Villa,Vázquez, Patricia Graciela,Sathicq, ángel Gabriel,Romanelli, Gustavo Pablo
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p. 826 - 832
(2018/11/06)
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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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- A very simple solvent-free method for the synthesis of 2-arylchromones using KHSO4 as a recyclable catalyst
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An efficient and solvent-free procedure for the synthesis of flavones using KHSO4 as a recyclable catalyst is described. The methodology represents an environmentally friendly process in comprehensive consideration compared with other catalytic systems listed in publications. This method provides a clean, simple, solvent-free reaction and useful alternatives to prepare flavones and chromones. The use of KHSO4 catalyst provides excellent yields, also leading to an easy separation and recovery of the catalysts, which allows both low environmental impact and low cost. Other green advantages of the method are the low formation of wastes and the replacement of corrosive, soluble mineral acids.
- Pérez, María,Ruiz, Diego,Autino, Juan,Sathicq, Angel,Romanelli, Gustavo
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p. 551 - 555
(2016/06/01)
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- Synthesis of flavones and γ-benzopyranones using mild sonogashira coupling and 18-crown-6 ether mediated 6-endo cyclization
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An efficient method for the synthesis of flavones and γ- benzopyranones has been developed utilizing a mild Sonogashira coupling and 18-crown-6 ether mediated 6-endo cyclization of o-alkynoylphenyl acetates. By using this strategy, flavones and γ-benzopyranones bearing electron-donating groups, halogens, and simple alkyl substituents were synthesized in satisfactory yields. A facile, mild, and selective method for the synthesis of flavones and γ-benzopyranones is reported. o-Alkynoylphenyl acetates were obtained from either acyl chloride derivatives or substituted salicylates. Upon removing the acetate group, flavones and γ- benzopyranones were synthesized within 15 min with the aid of 18-crown-6 ether. A library of flavones and γ-benzopyranones was established. Copyright
- Chuang, Da-Wei,El-Shazly, Mohamed,Balaji D., Barve,Chung, Yu-Ming,Chang, Fang-Rong,Wu, Yang-Chang
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p. 4533 - 4540,8
(2020/08/31)
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- A new synthesis of novel alkenylated flavones by palladium-catalyzed cross-coupling reactions
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Bromoflavones were treated with various terminal alkynes in palladium-catalyzed cross-coupling reactions under phosphine-free condions to give the expected alkenylated flavones in moderate to good yields. The presence of two different β hydrogens in the t
- Fekete, Szabolcs,Patonay, Tamas,Silva, Artur M. S.,Cavaleiro, Jose A. S.
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p. 210 - 225
(2013/09/24)
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- BENZENE-FUSED 6-MEMBERED OXYGEN-CONTAINING HETEROCYCLIC DERIVATIVES OF BICYCLIC HETEROARYLS
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The invention relates to new derivatives of formula I, wherein the substituents are as defined in the specification; to processes for the preparation of such derivatives; pharmaceutical compositions comprising such derivatives; such derivatives as a medicament; such derivatives for the treatment of a proliferative disease.
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Page/Page column 56
(2011/06/23)
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- Wells-Dawson heteropolyacid as reusable catalyst for sustainable synthesis of flavones
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The behavior of Wells-Dawson (H6P2W 18O62·24H2O, WD) acid, both bulk and supported on silica, for the cyclodehydration reaction of 1-(2-hydroxyphenyl)-3- phenyl-1,3-propanedione to obtain flavone was studied in heterogeneous conditions, using toluene as solvent. Catalytic experiences with bulk and supported catalysts with different WD acid loadings and reuse of the catalysts were done. The catalytic activity of supported catalysts was higher than that of the bulk catalyst, and their activity was almost constant after three reaction cycles. The following reaction conditions: reflux toluene and 1% mmol of WD supported on silica (0.4 g WD acid by gram of silica) were used for the preparation of five flavones. Yields above 85% were obtained in 4-5 h.
- Bennardi, Daniel O.,Romanelli, Gustavo P.,Sathicq, ángel G.,Autino, Juan C.,Baronetti, Graciela T.,Thomas, Horacio J.
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experimental part
p. 68 - 73
(2012/02/05)
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- Synthesis of substituted flavones and arylchromones using P and Si Keggin heteropolyacids as catalysts
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A simple and clean procedure for the preparation of functionalized flavones and chromones using commercial Keggin heteropolyacid in acetonitrile medium is described for the cyclization of 1-(2-hydroxyaryl)-3-aryl-1,3-propanodiones. Sixteen examples are reported, yields ranging in 60-91%; five substituted 2-naphthylchromones are prepared for the first time.
- Bennardi, Daniel O.,Romanelli, Gustavo P.,Jios, Jorge L.,Vazquez, Patricia G.,Caceres, Carmen V.,Autino, Juan C.
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- Flavonoid and biflavonoid derivatives, their pharmaceutical compositions, their anxiolytic activity
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Certain flavonoids, notably derivatives of flavone, chrysin and apigenin, together with dimers thereof such as amentoflavone, have been found to possess anxiolytic properties (i.e., anxiety reducing properties) without exhibiting a sedative effect. Novel
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