- Palladium-catalyzed carbonylation reaction of aryl bromides with 2-hydroxyacetophenones to form flavones
-
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
-
-
Read Online
- Dehydrogenation of flavanones to flavones using thallium(III) acetate(TTA)
-
A facile conversion of flavanones to flavones by dehydrogenation of the former using thallium(III) acetate is described.
- Singh, Om V.,Kapoor
-
-
Read Online
- Synthesis of 4H-Chromen-4-one Derivatives by Intramolecular Palladium-Catalyzed Acylation of Alkenyl Bromides with Aldehydes
-
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
-
-
Read Online
- Wells-Dawson heteropolyacid as reusable catalyst for sustainable synthesis of flavones
-
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.
-
-
Read Online
- CF3SOCl-promoted intramolecular cyclization of β-diketones: An efficient synthesis of flavones
-
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
-
-
Read Online
- Hypervalent iodine oxidation of flavanones: A new synthesis of methyl 2-aryl-2,3-dihydrobenzofuran-3-carboxylates by 1,2-aryl shift
-
Flavanones (1), on oxidation with (diacetoxyiodo)benzene-sulfuric acid (DIB-H2SO4) or (hydroxy(tosyloxy)iodo)benzene (HTIB) in trimethyl orthoformate, undergo facile ring contraction by 1,2-aryl shift, thereby yielding methyl 2-aryl-2,3-dihydrobenzofuran-3-carboxylates (4) as major products (40-80%). cis-3-Methoxyflavanones (5) and flavones (3) are the minor products formed in variable ratios.
- Prakash,Tanwar
-
-
Read Online
- An efficient TBHP/TBAI-mediated protocol for the synthesis of 4H-chromen-4-ones from chroman-4-ones via oxidative C–C bond formation
-
Abstract: A transition metal-free and efficient TBHP/TBAI-mediated protocol has been developed for the synthesis of 4H-chromen-4-ones from chroman-4-ones via oxidative C–C bond formation. It proceeds in the presence of a catalytic amount of tetrabutylammonium iodide and oxidant tert-butyl hydroperoxide (TBHP, 5–6 M in decane) to afford the corresponding products in good to excellent yields. Furthermore, it has been observed that an increase in the concentration of TBHP to 30 mol % drastically increases the yield of 4H-chromen-4-ones, any further increase will lead to a decrease in percent yield. The mechanism of this reaction involves the generation of tertiary butoxide radical initially which by oxidative single-electron transformation is converted to iodochroman-4-one. Later the hydrogen iodide is removed from iodochroman-4-one to give the desired product, i.e. 4H-chromen-4-ones. Moreover, this is a rare example of the n-Bu4NI/TBHP-mediated C–C bond through dehydrogenative reaction. Graphic abstract: [Figure not available: see fulltext.]
- Agisho, Habtamu Abebe,Hairat, Suboot,Zaki, Mehvash
-
-
Read Online
- A very simple solvent-free method for the synthesis of 2-arylchromones using KHSO4 as a recyclable catalyst
-
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
-
-
Read Online
- Rhodium(III)-catalyzed one-pot synthesis of flavonoids from salicylaldehydes and sulfoxonium ylides
-
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
-
-
Read Online
- Ru(II)-catalyzed C-H activation and annulation of salicylaldehydes with monosubstituted and disubstituted alkynes
-
The Ru(ii)-catalyzed C-H activation and annulation reaction of salicylaldehydes and disubstituted alkynes affords chromones in high yields. This reaction also works with terminal alkynes and tolerates a wide range of sensitive functional groups. The selectivity pattern of this Ru(ii)-catalyzed annulation reaction is different from the known Au(i), Rh(iii)-catalyzed annulation reactions of salicylaldehydes and terminal alkynes.
- Baruah, Swagata,Kaishap, Partha Pratim,Gogoi, Sanjib
-
-
Read Online
- Microwave assisted efficient synthesis of flavone using ZnO nanoparticles as promoter under solvent-free conditions
-
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.
-
-
Read Online
- Single Step Synthetic Method for Homoisoflavonoids and Flavones
-
The present invention relates to a one-pot synthesis method of homoisoflavonoid derivatives and flavone derivatives. By conducting a reaction of salicylicaldehyde and arylalkynoic acid in the presence of a ruthenium catalyst and a base, homoisoflavonoids and flavones can be selectively obtained through a single step (one-pot). Therefore, a synthesis method of the present invention is a simple/disposable selective metal catalyst synthesis method, which can be used to manufacture a plurality of bioactive materials.COPYRIGHT KIPO 2019
- -
-
Paragraph 0071; 0354-0358; 0360; 0362-0365; 0382-0385
(2019/09/12)
-
- An efficient tandem synthesis of chromones from: O -bromoaryl ynones and benzaldehyde oxime
-
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
-
p. 7461 - 7467
(2019/08/20)
-
- A 2 - aryl flavone preparation method
-
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.
- -
-
Paragraph 0034; 0035; 0036; 0037
(2018/07/15)
-
- Green and efficient synthesis of flavones and chromones using heteropolyacids as catalyst in glycerol
-
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
-
p. 826 - 832
(2018/11/06)
-
- One-pot Synthesis of Aurones through Oxidation-cyclization Tandem Reaction Catalyzed by Copper Nanoparticles Catalyst
-
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
-
-
- Divergent synthesis of flavones and aurones via base-controlled regioselective palladium catalyzed carbonylative cyclization
-
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
-
p. 264 - 270
(2018/05/04)
-
- Silver-catalyzed Double Decarboxylative Radical Alkynylation/Annulation of Arylpropiolic Acids with α-keto Acids: Access to Ynones and Flavones under Mild Conditions
-
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
-
supporting information
p. 1218 - 1231
(2018/02/16)
-
- One-Pot Allan–Robinson/Friedl?nder Route to Chromen-/Quinolin-4-ones through the Domino Acetylative Cyclisation of 2-Hydroxy-/2-Aminobenzaldehydes
-
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
-
p. 537 - 544
(2018/02/09)
-
- One Pot Synthesis of γ-Benzopyranones via Iron-Catalyzed Aerobic Oxidation and Subsequent 4-Dimethylaminopyridine Catalyzed 6-endo Cyclization
-
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
-
supporting information
p. 153 - 160
(2017/11/23)
-
- The five carbonyl iron as CO release source preparation benzopyranone compounds (by machine translation)
-
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)
- -
-
Paragraph 0014; 0039-0042
(2017/07/06)
-
- Ruthenium-Catalyzed C-H Activation of Salicylaldehyde and Decarboxylative Coupling of Alkynoic Acids for the Selective Synthesis of Homoisoflavonoids and Flavones
-
Homoisoflavonoids were formed in DMSO exclusively, and flavones were formed in t-AmOH when salicylaldehyde and alkynoic acids reacted with [Ru(p-cymene)Cl2]2 and CsOAc. They were formed through C-H activation of salicylaldehyde and decarboxylative coupling of alkynoic acid. This reaction system showed good yields, broad substrate scope, and good functional group tolerance. It was found that chalcone was an intermediate in the formation of both homoisoflavonoid and flavone.
- Raja, Gabriel Charles Edwin,Ryu, Ji Yeon,Lee, Junseong,Lee, Sunwoo
-
supporting information
p. 6606 - 6609
(2017/12/26)
-
- 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
-
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
-
p. 2613 - 2616
(2017/05/10)
-
- L-ascorbic acid: A green and competent promoter for solvent-free synthesis of flavones and coumarins under conventional as well as microwave heating
-
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
-
p. 734 - 741
(2017/02/05)
-
- Ammonium acetate promoted rapid and efficient synthesis of γ-Benzopyranones and 3,4-dihydropyrimidin-2(1H)-ones/thiones under solventfree conditions: A parallel scrutiny of microwave irradiation versus conventional heating
-
Simple and highly efficient approach for the synthesis of γ-Benzopyranones and 3,4-Dihydropyrimidin-2(1H)-ones/thiones using ammonium acetate as a promoter under thermal as well as microwave irradiation using solvent-free conditions has been demonstrated.
- Thorat, Nitin M.,Dengale, Rohit A.,Thopate, Shankar R.,Rohokale, Sandeep V.
-
p. 574 - 583
(2015/10/05)
-
- A versatile approach to flavones via a one-pot Pd(II)-catalyzed dehydrogenation/oxidative boron-Heck coupling sequence of chromanones
-
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
-
p. 777 - 784
(2016/01/12)
-
- Pd(OAc)2/S=PPh3 accelerated activation of gem-dichloroalkenes for the construction of 3-arylchromones
-
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
-
supporting information
p. 17576 - 17579
(2015/12/08)
-
- An efficient synthesis of aurone derivatives by the tributylphosphine-catalyzed regioselective cyclization of o-alkynoylphenols
-
An organocatalytic regioselective synthes is of aurones from o-alkynoylphenols was achieved. A catalytic amount of tributylphosphine select ively induced the 5-exo cyclization of o-alkynoylphenols under ambient conditions leading to aurone derivatives in high to excellent yields.
- Saito, Koya,Yoshida, Masahito,Doi, Takayuki
-
supporting information
p. 141 - 143
(2015/02/19)
-
- Iodine catalyzed cascade synthesis of flavone derivatives from 2'-allyloxy-α,β-dibromochalcones
-
Synthesis of flavones from 2'-allyloxy-α, β-dibromochalcones has been described. The iodine induced oxidative cyclization of 2'-allyloxy-α, β-dibromochalcones results into the formation of 3-bromoflavanones which ultimately gives flavones. Dehydrobromination of 3-bromoflavanone to give flavone is the preferred reaction over dehydrogenation.
- Nawghare, Beena R.,Gaikwad, Sunil V.,Raheem, Abdul,Lokhande, Pradeep D.
-
p. 2284 - 2286
(2014/07/22)
-
- An efficient and green synthesis of flavones using natural organic acids as promoter under solvent-free condition
-
An efficient and eco-friendly synthesis of flavones, promoted by naturally occurring acids, via cyclodehydration of 1-(2-hydroxyphenyl)-3-aryl-1,3- propanediones using conventional and microwave heating under solvent-free condition is described.
- Thorat, Nitin M.,Kote, Santosh R.,Thopate, Shankar R.
-
p. 601 - 605
(2014/07/21)
-
- FeCl3 and ether mediated direct intramolecular acylation of esters and their application in efficient preparation of xanthone and chromone derivatives
-
The direct intramolecular acylation of esters was developed by using the combined system of FeCl3 with Cl2CHOCH3. This unique cooperative system offered a new and efficient approach to biologically important xanthone and chromone derivatives with regioselectivity. Examples were reported, and control experiments were carried out to examine the effect of the benzyl esters and Cl2CHOCH3.
- Jiang, Neng,Li, Su-Yi,Xie, Sai-Sai,Yao, Hequan,Sun, Hongbin,Wang, Xiao-Bing,Kong, Ling-Yi
-
p. 63632 - 63641
(2015/02/19)
-
- Ferrocenyl flavonoid-induced morphological modifications of endothelial cells and cytotoxicity against B16 murine melanoma cells
-
With the aim of improving the cytotoxic and vascular disrupting activities of flavonoids, several classes of ferrocenyl-modified flavonoids were prepared and tested on cancer and endothelial cells. Three ten-member series of ferrocenyl flavonoids: chalcones ((E)-1-(R-2′-hydroxyphenyl)-3- ferrocenylprop-2-en-1-ones), aurones ((Z)-R-2-(ferrocenylidene)benzofuran-3- ones) and flavones (R-2-ferrocenyl-chromen-4-ones) were synthesized by recently reported methods. Three ferrocenyl flavonols (R-3-hydroxy-2-ferrocenyl-chromen- 4-ones) and four ferrocenyl flavanones (3-ferrocenylmethylidenyl-R-2- phenylchroman-4-ones) were also obtained. All compounds were evaluated for their cytotoxic effects on a cancer cell line (B16 murine melanoma) and for their morphological effects on endothelial cells (EAhy 926). Some interesting structure-activity relationships were disclosed: of all the compounds, the halogen-substituted aurones showed the best cytotoxic activity, with IC 50 values ranging between 12 and 18 μM. Ferrocenyl flavonols and ferrocenyl flavanones with substitution in the 3-position (-OH and C-Fc respectively) were not active against cancer or endothelial cells. Some of the ferrocenyl flavones caused the endothelial cells to adopt a round shape ("rounding up") at submicromolar concentrations, which can be predictive of vascular disrupting activity. The most morphologically active flavones showed only moderate cytotoxicity against cancer cells, indicating that they may primarily act as antivascular agents.
- Monserrat, Jean-Philippe,Tiwari, Keshri Nath,Quentin, Lionel,Pigeon, Pascal,Jaouen, Gérard,Vessières, Anne,Chabot, Guy G.,Hillard, Elizabeth A.
-
-
- Synthesis of chromones through LiOtBu/air-mediated oxidation and regioselective cyclization of o-hydroxyphenyl propargyl carbinols
-
A cascade oxidative cyclization reaction for the synthesis of chromone derivatives was developed by using LiOtBu as a mediator and air as an oxidant. The reaction was carried out without the assistance of a transition metal under mild conditions to afford the chromones in good yields with high regioselectivities. A tandem reaction for the synthesis of various chromones was developed. LiOtBu was used as a mediator and air was used as a clean oxidant. The reaction generally showed high regioselectivity under mild conditions. Extensive research showed that dehydrogenative oxidation of the alcohols under strongly basic conditions was the crucial step, and Li+ was also found to play an important role in this process. Copyright
- Zhang, Shuai,Wan, Changfeng,Wang, Qiang,Zhang, Baiqun,Gao, Lingfeng,Zha, Zhenggen,Wang, Zhiyong
-
p. 2080 - 2083
(2013/05/09)
-
- Palladium-catalyzed dehydrogenation/oxidative cross-coupling sequence of β-heteroatom-substituted ketones
-
Concise and selective: The title one-pot sequence allows formation of the enone functionality and subsequent cross-coupling. The process provides access to highly functionalized cyclic enolones and enaminones from readily accessible β-heteroatom-substitut
- Moon, Youngtaek,Kwon, Daeil,Hong, Sungwoo
-
supporting information
p. 11333 - 11336,4
(2012/12/12)
-
- Synthetic approach to flavanones and flavones via ligand-free palladium(ii)-catalyzed conjugate addition of arylboronic acids to chromones
-
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
-
experimental part
p. 7305 - 7312
(2012/09/22)
-
- Ionic liquid mediated Cu-catalyzed cascade oxa-Michael-oxidation: Efficient synthesis of flavones under mild reaction conditions
-
Flavonoids are a class of natural products, found in a wide range of vascular plants and dietary components. Their low toxicity and extensive biological activities, including anti-cancer and anti-bacterial, have made them attractive candidates to serve as therapeutic agents for many diseases. Herein, we disclose a highly efficient synthetic method of CuI-catalyzed cascade oxa-Michael-oxidation, using chalcones as substrates, mediated by the ionic liquid [bmim][NTf2] at a low temperature. This efficient synthetic method has demonstrated high synthetic utility and can afford flavones in good to high yields (up to 98%).
- Du, Zhiyun,Ng, Huifen,Zhang, Kun,Zeng, Huaqiang,Wang, Jian
-
scheme or table
p. 6930 - 6933
(2011/11/04)
-
- A new synthesis of flavones and pyranoflavone by intramolecular photochemical Wittig reaction in water
-
A new synthetic approach toward the synthesis of flavones and pyranoflavone has been developed by light induced intramolecular photochemical Wittig reaction in water onto aryloxycarbonyl groups and suitably substituted phosphonium bromides sans any phase transfer catalyst or promoter.
- Das, Jhantu,Ghosh, Somnath
-
p. 7189 - 7194
(2012/01/05)
-
- A novel one pot route to flavones under dual catalysis, an organo- and a Lewis acid catalyst
-
Substituted phenylacetylenes react with various o-hydroxy aromatic aldehydes under dual catalysis of piperidine and FeCl3 in refluxing toluene to yield flavones in good to excellent yield. Atmospheric oxygen acts as stoichiometric oxidant in the process. Some of these compounds had been recently reported to show fair insecticidal activity against Spodoptera frugiperda.
- Maiti, Gourhari,Karmakar, Rajiv,Bhattacharya, Rudraksha N.,Kayal, Utpal
-
supporting information; experimental part
p. 5610 - 5612
(2011/11/12)
-
- Transition-metal-free intramolecular Ullmann-type O-arylation: Synthesis of chromone derivatives
-
(Chemical Equation Presented) Expect the upexpected: A transition-metal- free approach to access chromone derivatives has been developed. The intramolecular O-arylation of substituted 1-(2-haloaryl)-propane-1,3-diones in DMF in the presence of K2CO3 gave the corresponding target products in good to excellent yields (see scheme; DMF = N,N′- dimethylformamide).
- Zhao, Jie,Zhao, Yufen,Fu, Hua
-
p. 3769 - 3773
(2011/05/15)
-
- A two step synthesis of BzR/GABAergic active flavones via a Wacker-related oxidation
-
A general route for the synthesis of biologically important flavones is reported via a two step sequence employing a catalytic Wacker-Cook oxidation4b as the key step.
- Lorenz, Michael,Shahjahan Kabir,Cook, James M.
-
experimental part
p. 1095 - 1098
(2010/04/05)
-
- Synthesis of substituted flavones and arylchromones using P and Si Keggin heteropolyacids as catalysts
-
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.
-
-
- A selective transformation of flavanones to 3-bromoflavones and flavones under microwave irradiation
-
This paper presents the first report of a highly selective transformation of flavanones to 3-bromoflavones or flavones by microwave irradiation of the corresponding flavanone reactants and N-bromosuccinimide (NBS) in the presence of a catalytic amount of 2,2′-azobis(isobutyronitrile) (AIBN). The combination of good to excellent yields, shorter reaction time (10 min), and high levels of functional group compatibility make this an attractive synthetic approach to 3-bromoflavones and flavones.
- Zhou, Zhongzhen,Zhao, Peiliang,Huang, Wei,Yang, Guangfu
-
-
- Microwave-assisted synthesis of functionalized flavones and chromones
-
A facile microwave synthesis of functionalized flavones and chromones via the cyclization of 1-(2-hydroxyaryl)-3-aryl-1,3-propanedione is described.
- Kabalka, George W.,Mereddy, Arjun R.
-
p. 6315 - 6317
(2007/10/03)
-
- Manganese(III) acetate mediated oxidation of flavanones: A facile synthesis of flavones
-
Oxidation of flavanones (1a-o) with manganese(III) acetate by heating in acetic acid in presence of perchloric acid afforded exclusively flavones (2a-o) by dehydrogenation in almost quantitative yields. Copyright Taylor & Francis, Inc.
- Singh, Om V.,Muthukrishnan,Raj, Gopan
-
p. 2723 - 2728
(2007/10/03)
-
- Dimethylsulfoxide-iodine catalysed deprotection of 2′- allyloxychalcones: Synthesis of flavones
-
A new one-pot method is described for the removal of O-allyl protecting groups under oxidative conditions at neutral pH. 2′-Allyloxychalcones undergo deprotection and subsequent oxidative cyclisation to give flavones. The general applicability of the reagent has been studied.
- Lokhande, Pradeep D.,Sakate, Sachin S.,Taksande, Kiran N.,Navghare, Beena
-
p. 1573 - 1574
(2007/10/03)
-
- A Novel Synthesis of 4H-Chromen-4-ones via Intramolecular Wittig Reaction
-
formula presented The acylphosphoranes formed in a sequential manner from the reaction of the silyl ester of O-acyl(aroyl)salicylic acids and (trimethylsilyl)-methylenetriphenylphosphorane undergo intramolecular Wittig cyclization on the ester carbonyl to afford the 4H-chromen-4-ones in good to excellent yields.
- Kumar, Pradeep,Bodas, Mandar S.
-
p. 3821 - 3823
(2007/10/03)
-
- Synthesis of halogenated/nitrated flavone derivatives and evaluation of their affinity for the central benzodiazepine receptor
-
A series of halogenated/nitrated flavone compounds were synthesized. Some of the products were found to be potent central benzodiazepine receptor (BDZ-R) ligands. The structure-activity relationships (SAR) analysis of the new synthetic compounds, together with that of others already described, indicates that substitutions at position 6 or 6 and 3' in the flavone nucleus are the only ones that give rise to high affinity BDZ-R ligands.
- Marder, Mariel,Zinczuk, Juan,Colombo, Maria I.,Wasowski, Cristina,Viola, Haydee,Wolfman, Claudia,Medina, Jorge H.,Ruveda, Edmundo A.,Paladini, Alejandro C.
-
p. 2003 - 2008
(2007/10/03)
-
- Synthesis and biological activities of flavonoid derivatives as A3 adenosine receptor antagonists
-
A broad screening of phytochemicals has demonstrated that certain flavone and flavonol derivatives have a relatively high affinity at A3 adenosine receptors, with K(i) values of ≥1 μM (Ji et al. J. Med. Chem. 1996, 39, 781-788). We have further modified the flavone structure to achieve a degree of selectivity for cloned human brain A3 receptors, determined in competitive binding assays versus [125I]AB-MECA [N6-(4-amino-3- iodebenzyl)adenosine-5'-(N-methyluronamide)]. Affinity was determined in radioligand binding assays at rat brain A1 and A(2A) receptors using [3H]- N6-PIA ([3H]-(R)-N6-phenylisopropyladenosine) and [3H]CGS21680 [[3H]-2- [[4-(2-carboxyethyl)phenyl]ethylamino]-5'-(N-ethylcarbamoyl)adenosine], respectively. The triethyl and tripropyl ether derivatives of the flavonol galangin, 4, had K(i) values of 0.3-0.4 μM at human A3 receptors. The presence of a 5-hydroxyl group increased selectivity of flavonols for human A3 receptors. The 2',3,4',7-tetraethyl ether derivative of the flavonol morin, 7, displayed a K(i) value of 4.8 μM at human A3 receptors and was inactive at rat A1/A(2A) receptors. 3,6-Dichloro-2'-(isopropyloxy)-4'- methylflavone, 11e, was both potent and highly selective (~200-fold) for human A3 receptors (K(i) = 0.56 μM). Among dihydroflavonol analogues, the 2-styryl instead of the 2-aryl substituent, in 15, afforded selectivity for human A3 vs rat A1 or A(2A) receptors. The 2-styryl-6-propoxy derivative, 20, of the furanochromone visnagin was 30-fold selective for human A3 receptors vs either rat A1 or A(2A) receptors. Several of the more potent derivatives effectively antagonized the effects of an agonist in a functional A3 receptor assay, i.e. inhibition of adenylyl cyclase in CHO cells expressing cloned rat A3 receptors. In conclusion, these series of flavonoids provide leads for the development of novel potent and subtype selective A3 antagonists.
- Karton, Yishai,Jiang, Ji-Long,Ji, Xiao-Duo,Melman, Neli,Olah, Mark E.,Stiles, Gary L.,Jacobson, Kenneth A.
-
p. 2293 - 2301
(2007/10/03)
-
- Hypervalent Iodine Oxidation of Flawanones: Convenient and Useful Syntheses of Flavones and IsoFlavones
-
Hypervalent iodine oxidation of flavanones (1a-g) under a variety of conditions, offering convenient and valuable routes to the syntheses of flavones (2a-g) and isoflavones (3a-g), is described.The course of these oxidation reactions is greatly influenced by the reaction conditions and it is possible to select appropriate conditions for following a desired route (2/3).The mechanistic rationale for these transformations is also discussed.
- Prakash, Om,Tanwar, Madan P.
-
p. 1429 - 1447
(2007/10/02)
-
- Oxidation of Flavanones using Thallium(III) Salts: A New Route for the Synthesis of Flavones and Isoflavones
-
When treated with thallium(III) acetate in acetic acid or acetonitrile, flavanones undergo facile dehydrogenation to afford flavones whereas, upon treatment with thallium(III) toluene-p-sulfonate or thallium(III) nitrate in propionitrile or acetonitrile, respectively, they undergo oxidative 2,3-aryl migration to give isoflavones in high yield.
- Khanna, Mahavir S.,Singh, Om V.,Garg, Chandra P.,Kapoor, Ram P.
-
p. 2565 - 2568
(2007/10/02)
-
- FLAVONE FORMATION IN THE WHEELER AURONE SYNTHESIS
-
Dihydrochalcones, formed by bromomethylation of the side-chain of 2'-acetoxychalcones, were found to produce minor quantities of flavones as well as the major product, aurones, when cyclized by aqueous ethanolic sodium hydroxide.The yields of flavone increased with increasing base concentration.The optimum concentration of hydroxide for aurone formation was below 1percent.Greatly diminished yields of O-heterocycles were obtained when a nitro substituent was introduced para to the cyclizing 2'-oxy function.
- Donnelly, John A.,Higginbotham, Clement L.
-
p. 7219 - 7226
(2007/10/02)
-