- Insect antifeedant activity of flavones and chromones against Spodoptera litura
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The antifeedant polymethylated flavones 5-hydroxy-3,6,7,8,4′-heptamethoxyflavone, 5-hydroxy-3,6,7,8-tetramethoxyflavone, and 5,6-dihydroxy-3,7-dimethoxyflavone have been isolated from the cudweed, Gnaphalium affine D. Don (Compositae). These flavonoids and authentic analogues showed insect antifeedant activity against the common cutworm (Spodoptera litura F.). In a previous paper, it was suggested that there was no substituent on the B-ring of the flavonoid for the beneficial antifeedant activity against the common cutworm. These flavonoids having a phenyl group as the B-ring and the chromone as elimination of the B-ring from the flavonoids were used to test the hypothesis of the previously described B-ring effect. The known fact is that Sculletaria baicarensis (Rutaceae) produced the 2-phenyl flavone. Test compounds and their methylated derivatives were prepared from this material for the structure-activity relationship (SAR) study of insect antifeedant activity. In spite of the 2-phenyl flavonoids, some tested compounds did not show any insect antifeedant activity against the common cutworm, although these inactive flavonoids were deficient in the 6-substituent group on the A-ring of the flavonoid. This 6-position-substituted derivative almost showed strong insect antifeedant activity against common cutworm. Moreover, the tested flavonoids having a hydroxyl group as a substituent on any of the positions tended to increase the activity. These results suggested the importance of the 6-position substitution on the flavonoid; however, hydrophilic substituents decreased the activity. Baicalein (5,6,7-trihydroxyflavone) derivatives did not show any activity despite having the 6-substituent derivative. Although the activity of some chromones increased the activity of the flavone, the bulky B-ring was a disadvantage for the antifeedant activity. It was suggested that the charge on C(3) and C(5) of the flavonoid was important for the biological activity. Additionally, an adequate hydrogen bonding property, which is different from lipophilicity, was an advantage for the activity on the basis of a QSAR analysis.
- Morimoto, Masanori,Tanimoto, Kumiko,Nakano, Sachiko,Ozaki, Takayoshi,Nakano, Ayako,Komai, Koichiro
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Read Online
- Relaxant effect of structurally related flavonoids on isolated tracheal rat rings: a SAR study
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In the search for potential new antiasthmatic drugs, the ex vivo relaxing effect and structural activity relationship (SAR) studies of a series of ten structurally related flavonoids were established. Also, glycosylated and prenylated flavonoids were incl
- Flores-Flores, Angélica,Hidalgo-Figueroa, Sergio,Villalobos-Molina, Rafael,Ibarra-Barajas, Maximiliano,Bazán-Perkins, Blanca,Navarrete-Vázquez, Gabriel,Estrada-Soto, Samuel
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Read Online
- Discovery of polymethoxyflavones as potential cyclooxygenase-2 (COX-2), 5-lipoxygenase (5-LOX) and phosphodiesterase 4B (PDE4B) inhibitors
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Non-steroidal anti-inflammatory drugs (NSAIDs) are widely prescribed to treat inflammatory-related diseases, pain and fever. However, the prolong use of traditional NSAIDs leads to undesirable side effects such as gastric, ulceration, and renal toxicity due to lack of selectivity toward respective targets for COX-2, 5-LOX, and PDE4B. Thus, targeting multiple sites can reduce these adverse effects of the drugs and increase its potency. A series of methoxyflavones (F1–F5) were synthesized and investigated for their anti-inflammatory properties through molecular docking and inhibition assays. Among these flavones, only F2 exhibited selectivity toward COX-2 (Selectivity Index, SI: 3.90, COX-2 inhibition: 98.96 ± 1.47%) in comparison with celecoxib (SI: 7.54, COX-2 inhibition: 98.20 ± 2.55%). For PDEs, F3 possessed better selectivity to PDE4B (SI: 4.67) than rolipram (SI: 0.78). F5 had the best 5-LOX inhibitory activity among the flavones (33.65 ± 4.74%) but less than zileuton (90.81 ± 0.19%). Docking analysis indicated that the position of methoxy group and the substitution of halogen play role in determining the bioactivities of flavones. Interestingly, F1–F5 displayed favorable pharmacokinetic profiles and acceptable range of toxicity (IC50>70 μM) in cell lines with the exception for F1 (IC50: 16.02 ± 1.165 μM). This study generated valuable insight in designing new anti-inflammatory drug based on flavone scaffold. The newly synthesized flavones can be further developed as future therapeutic agents against inflammation.
- Hamzah, Ahmad Sazali,Md Idris, Muhd Hanis,Mohd Amin, Siti Norhidayah,Mohd Amin, Siti Norhidayu,Salleh, Mohd Zaki,Selvaraj, Manikandan,Shaameri, Zurina,Teh, Lay Kek,Wibowo, Agustono,Zakaria, Zainul Amiruddin
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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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- A novel one-pot synthesis of flavones
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In this paper, a one-pot facile route for the BiCl3/RuCl3-mediated synthesis of functionalized flavones is described, including: (i) intermolecularortho-acylation of substituted phenols with cinnamoyl chlorides, and (ii) intramolecular cyclodehydrogenation of the resultingo-hydroxychalcones. The reaction conditions are discussed herein.
- Chang, Meng-Yang,Tsai, Min-Chen,Lin, Chun-Yi
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p. 11655 - 11662
(2021/03/31)
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- Thermally regulated molybdate-based ionic liquids toward molecular oxygen activation for one-pot oxidative cascade catalysis
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One-pot oxidative cascade catalysis plays a central role in the synthesis of key pharmaceutical and industrial molecules. Although ionic liquids are one of the most promising solvents and reaction media, the breakthrough of their catalysis in aerobic oxidation is very challenging due to the difficulty in the direct activation of molecular oxygen. Herein, a family of novel thermally regulated molybdate-based ionic liquids (Mo-ILs) has been designed and developed for the first time toward molecular oxygen activation for highly efficient tandem oxidative catalysis. Three diverse one-pot oxidative cascade processes for the syntheses of various flavones, imines, and benzyl benzoates were achieved with good to excellent yields using the Mo-IL [Bmim]2[MoO4] as a catalyst under air conditions. The results of spectroscopic investigations and quantum-chemical calculations further demonstrated that a thermally regulated proton migration between the cation [Bmim] and anion [MoO4] was the key to forming N-heterocyclic carbene and thereby to effortlessly promoting the generation of O2- active species from molecular oxygen, which results in excellent catalytic performance in these three aerobic tandem oxidations. Our work extends the application area of ILs as the sole catalyst to one-pot aerobic oxidative cascade catalysis, which could have pronounced implications in future work.
- Song, Zhibin,Huang, Wei,Zhou, Yan,Tian, Zi-Qi,Li, Zhang-Min,Tao, Duan-Jian
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p. 103 - 109
(2020/01/21)
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- An efficient TBHP/TBAI-mediated protocol for the synthesis of 4H-chromen-4-ones from chroman-4-ones via oxidative C–C bond formation
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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
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p. 599 - 603
(2020/05/04)
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- CeO2-Supported Pd(II)-on-Au Nanoparticle Catalyst for Aerobic Selective α,β-Desaturation of Carbonyl Compounds Applicable to Cyclohexanones
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Direct selective desaturation of carbonyl compounds to synthesize α,β-unsaturated carbonyl compounds represents an environmentally benign alternative to classical stepwise procedures. In this study, we designed an ideal CeO2-supported Pd(II)-on-Au nanoparticle catalyst (Pd/Au/CeO2) and successfully achieved heterogeneously catalyzed selective desaturation of cyclohexanones to cyclohexenones using O2 in air as the oxidant. Besides cyclohexenones, various bioactive enones can also be synthesized from the corresponding saturated ketones under open air conditions in the presence of Pd/Au/CeO2. Preliminary mechanistic studies revealed that α-C-H bond cleavage in the substrates is the turnover-limiting step of this desaturation reaction.
- Jin, Xiongjie,Mizuno, Noritaka,Takei, Daisuke,Yabe, Tomohiro,Yamaguchi, Kazuya,Yatabe, Takafumi
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p. 5057 - 5063
(2020/05/27)
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- Single Step Synthetic Method for Homoisoflavonoids and Flavones
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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
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Paragraph 0071; 0354-0358; 0360; 0362-0365; 0372-0375
(2019/09/12)
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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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- Microwave assisted efficient synthesis of flavone using ZnO nanoparticles as promoter under solvent-free conditions
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A simple and highly efficient protocol for synthesis of flavones from 1-(2-hydroxyphenyl)-3-aryl-1,3-propanediones in presence of ZnO nanoparticles as a promoter in thermal as well as microwave irradiation under solvent-free conditions have been demonstrated. The catalyst is inexpensive, stable, can be easily recycled/reused for several cycles with consistent activity and observed almost same yield confirming the stability of the catalyst. It is believed that the present approach will become an alternative route for the conventional reactions. Because in this protocol, yield is quite high, short reaction time, simple work up, catalyst can be recycled as well as it is free of any hazardous by-products formation during workup.
- Unde, Pradip J.,Thorat, Nitin M.,Patil, Limbraj R.
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p. 1133 - 1136
(2019/04/05)
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- 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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- A 2 - aryl flavone preparation method
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The invention discloses a 2 - aryl flavone preparation method, including: in the silver catalyst and under the action of the oxidizing agent, ortho-hydroxy aryl formyl formic acid and aryl alkynoic ring reaction in a solvent, after the reaction is finished after treatment to obtain the 2 - aryl flavone. The method of this invention easily obtained and cheap agents, mild reaction conditions, reaction functional group compatibility is good, cheap catalyst, the catalytic system is simple.
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Paragraph 0034; 0035; 0036; 0037
(2018/07/15)
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- Silver-catalyzed Double Decarboxylative Radical Alkynylation/Annulation of Arylpropiolic Acids with α-keto Acids: Access to Ynones and Flavones under Mild Conditions
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Ynones are privileged building blocks in various organic syntheses of heterocyclic derivatives due to their multifunctional nature, and flavones are an important class of natural products with a wide range of biological activities. We describe the catalytic double decarboxylative alkynylation of arylpropiolic acids with α-keto acids. With Ag(I)/persulfate as the catalysis system, the valuable ynones bearing various substituents could be easily obtained. The introduction of hydroxyl substituent on ortho-site of α-keto acids make this strategy further applicable to the construction of flavone derivatives via heteroannulation in moderate to good yields with a similar silver-catalyzed system. The reactions proceed under relatively mild reaction conditions and tolerate a wide variety of functional groups. Control experiments indicated that both the reactions undergo radical processes. (Figure presented.).
- Meng, Mengting,Wang, Guofang,Yang, Liangfeng,Cheng, Kai,Qi, Chenze
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supporting information
p. 1218 - 1231
(2018/02/16)
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- Rational design for multicolor flavone-based fluorophores with aggregation-induced emission enhancement characteristics and applications in mitochondria-imaging
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Fluorophores with aggregation-induced emission enhancement (AIEE) properties have attracted more attention in recent years. In order to realise more valuable applications, the different kinds of AIEE molecules are in serious need of further development. Therefore, a novel flavone-based AIEE system derived from restriction of intramolecular rotation (RIR) was designed and synthesized in this work. The results revealed that six of the compounds showed typical AIEE characteristics, with fluorescence emissions from purple, blue, cyan to green, tunable by changing substituent groups. This flavone-based AIEE system has never been reported before. The AIEE characteristics were investigated by optical spectroscopy, fluorescence photographs, scanning electron microscopy (SEM), fluorescence quantum yields (φF) and fluorescence lifetime in the CH3OH/H2O mixed solution. Moreover, benefiting from the simple structures and small molecular weight, they could permeate cells faster than current high-molecular-weight AIEE molecules. Furthermore, to examine possible biomedical applications, fluorescence imaging in living A549 lung cells and cell viabilities were examined, and the results displayed that these fluorophores showed good cellular uptake and low cytotoxicity within the experimental concentration range. In addition, these AIEE compounds possessed excellent specificity for mitochondrial targeting and mitochondrial morphological change tracking, besides, they displayed superior photostability, which indicated they are potential candidates for mitochondrial imaging.
- Liu, Liyan,Lei, Yaohui,Zhang, Jianhui,Li, Na,Zhang, Fan,Wang, Huaqiao,He, Feng
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- 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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- 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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- Ruthenium-Catalyzed C-H Activation of Salicylaldehyde and Decarboxylative Coupling of Alkynoic Acids for the Selective Synthesis of Homoisoflavonoids and Flavones
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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
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supporting information
p. 6606 - 6609
(2017/12/26)
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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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- Pd catalyzed couplings of “superactive esters” and terminal alkynes: Application to flavones and γ-benzopyranones construction
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Lewis base, N-methylmorpholine (NMM) accelerated Pd-catalyzed Sonogashira coupling of steric hindered super active esters, 1a–1e, and terminal alkynes. This approach provided an efficient synthetic protocol for a broad array of acylated o-alkynoylphenols compounds, 3a–3e, under moderate conditions. The mechanistic study clearly demonstrated that NNM stabilized the catalytic palladium species, and accelerated the leaving of triazine moiety during the catalytic cycle of the cross-coupling reactions. In addition, piperazine was found to efficiently catalyze the 6-endo cyclization of acylated o-alkynoylphenols, which achieved the diversity oriented synthesis of γ-benzopyranones, 4aa–4eg, with 93–99% yields.
- Yang, Dandan,Wang, Zhenhua,Wang, Xiu,Sun, Huaming,Xie, Zunyuan,Fan, Juan,Zhang, Guofang,Zhang, Weiqiang,Gao, Ziwei
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- 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 0035-0038
(2017/08/19)
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- Metal-free, Br?nsted acid-mediated synthesis of coumarin derivatives from phenols and propiolic acids
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A novel synthesis of coumarin derivatives by Br?nsted acid-mediated condensation and intramolecular cyclization of phenols and propiolic acids was reported. This transformation requires the use of TfOH in place of a conventional metal mediator, and it occurs under mild conditions and provides rapid access to coumarin derivatives in good yields.
- Choi, Hyuck,Kim, Jaehyun,Lee, Kooyeon
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supporting information
p. 3600 - 3603
(2016/07/21)
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- Process for preparing coumarin derivatives using phenol and propiolic acid
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Provided is a manufacturing method of coumarin derivative. The manufacturing method of coumarin derivative comprises a step of making a phenol compound react with a propiolic acid compound. According to the present invention, the manufacturing method of coumarin derivative is quick and efficient, and is useful to fields requiring synthesis of coumarin derivatives of various structures.COPYRIGHT KIPO 2016
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Paragraph 0160; 0161
(2017/01/12)
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- Certain 4-iminoflavones derivatives: Synthesis, docking studies, antiasthmatic and antimicrobial agents
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In this present study, certain substituted 4-iminoflavone derivatives 5(a-j) were synthesized. All the synthesized compounds were evaluated for antiasthmatic and antimicrobial activity. Among the synthesized compounds, 5f was found to be the most promising against asthmatic models, whilst, 5h was found active against all the microbial strains. Antiasthmatic activity was correlated and evaluated with various models, e.g., citric acid induced cough model, OVA induced asthma model (biochemical estimation for cell infiltrations, estimation of lipid peroxidation and glutathione and estimation of TNF-α and IL-6 and histamine induced response). Compound 5f was found to show 2.20 ± 0.047 number of cough whilst codeine showed 1.40 ± 0.548; compound 5f produced considerable reduction in neutrophils, lymphocytes, eosinophils and leukocytes; decrease in LPO level (lung and BALF) and increment in GSH level (lungand BALF); and decreased the level of TNF-α and IL-6, respectively. On the other hand, 5h showed MIC 6.25 μg/mL against B. subtilis and S. aureus, 3.1 μg/mL against E. coli, 1.55 μg/mL against S. typhi and 6.25 μg/mL against C. albicans, respectively. In addition to gain better understanding on the biological activities of synthesized compounds, molecular docking study was performed within the binding site of human histamine H1 receptor and Glc-6-P synthase revealing compound 5f and 5h as best fit within the respective receptor pockets.
- Khah, Shaila,Goyal, Rohit,Chabba, Ankush,Jaiswal, Varun,Sharma, Gaurav,Naushad
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p. 1687 - 1696
(2016/07/06)
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- L-ascorbic acid: A green and competent promoter for solvent-free synthesis of flavones and coumarins under conventional as well as microwave heating
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Background: An expeditious approach has been developed for the synthesis of two distinct classes of benzopyrones viz. flavones and coumarins under solvent-free conditions. L-Ascorbic acid was found to be an effective promoter under microwave irradiation and conventional heating. Various benzo-α-pyrones and benzo-γ-pyrones were synthesized with overall good yields. The present protocol is highly facile and needs no column chromatography for purification and therefore it would serve as an effective and compatible method under both microwave irradiation and conventional heating. Results: The catalytic ability of L-ascorbic acid was investigated for the synthesis of flavones and coumarins. For this purpose, cyclodehydration of 1-(2-hydroxyphenyl)-3-aryl-1,3-propanedione and Pechmann coumarin synthesis, reactions were selected. And accordingly, it was observed that one mole of L-ascorbic acid was necessary for the completion of reaction. In all the cases, the desired flavones were smoothly generated with good to excellent yields; indicating its excellent tolerance for various functional groups. However, electron donating groups favors coumarin synthesis under these conditions. All the reaction mixtures were carefully analyzed and NMR indicates high conversions and lack of side products. Conclusion: We have developed L-ascorbic acid-promoted, solvent-free and simple method for the synthesis of benzo-α-pyrones and benzo-γ-pyrone under microwave irradiation as well as conventional heating in good to excellent yields. The notable advantages of this method are solvent-free conditions, inexpensive and efficient eco-friendly promoter, and shorter reaction time and can be carried out under air. This methodology is highly facile and requires no column chromatography for purification. The resulting flavones and coumarins are versatile building blocks in the construction of heterocyclic architectures, dominant in natural products. Further studies of exploiting the efficiency of L-ascorbic acid as a promoter in synthesis of various heterocyclic compounds are in progress.
- Dengale, Rohit Arvind,Thorat, Nitin Madhu,Thopate, Shankar Ramchandra
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p. 734 - 741
(2017/02/05)
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- Gold nanoparticles on OMS-2 for heterogeneously catalyzed aerobic oxidative α,β-dehydrogenation of β-heteroatom-substituted ketones
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In the presence of Au nanoparticles supported on manganese oxide OMS-2 (Au/OMS-2), various kinds of β-heteroatom-substituted α,β-unsaturated ketones (heteroatom = N, O, S) can be synthesized through α,β-dehydrogenation of the corresponding saturated ketones using O2 (in air) as the oxidant. The catalysis of Au/OMS-2 is truly heterogeneous, and the catalyst can be reused.
- Yoshii, Daichi,Jin, Xiongjie,Yatabe, Takafumi,Hasegawa, Jun-ya,Yamaguchi, Kazuya,Mizuno, Noritaka
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supporting information
p. 14314 - 14317
(2016/12/14)
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- Method for synthesizing flavonoids compound in one step by virtue of catalysis of 1,3-dialkylimidazolium oxometallate
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The invention discloses a method for synthesizing a flavonoids compound in one step by virtue of catalysis of 1,3-dialkylimidazolium oxometallate. The method is characterized by comprising the following steps: sequentially adding raw material benzaldehyde or benzaldehyde derivatives, raw material 2-hydroxyacetophenone or 2-hydroxyacetophenone derivatives, an ion liquid catalyst and an organic solvent into a reactor, stirring, heating to 50 to 90 DEG C, reacting for 2 to 7 hours at a constant temperature by taking oxygen or air as an oxidant, cooling, distilling under reduced pressure, carrying out the column chromatography, and re-crystallizing and separating to obtain the target product flavonoids compound. The method has the characteristics that the ion liquid is used as the catalyst, the yield of the flavonoids compound synthesized in one step reaches 85 percent or more, therefore, compared with the traditional synthetic method, the reaction flow is shortened, and the synthetic efficiency of the flavonoids compound is remarkably improved. The method has advantages of high product yield, low production cost, simple operation procedures, moderate reaction conditions and the like and is proved to be a novel method for high-efficiently synthesizing the flavonoids compound.
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Paragraph 0097; 0098; 0099
(2016/10/08)
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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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- 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
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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.
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p. 574 - 583
(2015/10/05)
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- PPh3·HBr-DMSO: A Reagent System for Diverse Chemoselective Transformations
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The broad applicability of the hitherto unexplored reagent combination PPh3·HBr-DMSO is exemplified with multiple highly diverse one-step transformations to synthetically useful building blocks, such as flavones, 4H-thiochromen-4-ones, α-hydroxy ketones, 1,4-naphthoquinones (including vitamin K3), 2-bromo-3-substituted-1H-1-indenones, 2-methylthio-1H-1-indenones, 3-butyne-1,2-dione, and 4-pentene-2,3-diones. The simple and mild reaction conditions make the reagent superior in terms of yield and substrate scope in comparison with the existing alternatives.
- Mal, Kanchan,Kaur, Amanpreet,Haque, Fazle,Das, Indrajit
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p. 6400 - 6410
(2015/06/30)
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- An efficient and green synthesis of flavones using natural organic acids as promoter under solvent-free condition
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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.
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p. 601 - 605
(2014/07/21)
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- FeCl3 and ether mediated direct intramolecular acylation of esters and their application in efficient preparation of xanthone and chromone derivatives
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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
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p. 63632 - 63641
(2015/02/19)
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- Convenient one-pot synthesis of chromone derivatives and their antifungal and antibacterial evaluation
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A one-pot method for the synthesis of chromone derivatives from the reaction of 2-hydroxyacetophenones with aliphatic or aromatic acid chlorides is reported. Esterification and Baker-Venkataraman rearrangement were promoted by t-BuOK, which was followed directly by acid-catalyzed cyclization in one pot. Some of 2-cyclohexyl- and 2-cyclohexylmethyl-substituted chromones displayed activity against plant pathogenic fungal strains. Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications1 to view the free supplemental file. Copyright Taylor & Francis Group, LLC.
- Ghani, Sherif B. Abdel,Mugisha, Patrick J.,Wilcox, Juliet C.,Gado, Emad A. M.,Medu, Erere O.,Lamb, Andrew J.,Brown, Richard C. D.
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p. 1549 - 1556
(2013/05/22)
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- Ferrocenyl flavonoid-induced morphological modifications of endothelial cells and cytotoxicity against B16 murine melanoma cells
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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.
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- Synthesis of chromones through LiOtBu/air-mediated oxidation and regioselective cyclization of o-hydroxyphenyl propargyl carbinols
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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
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p. 2080 - 2083
(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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- 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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- 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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- Ionic liquid mediated Cu-catalyzed cascade oxa-Michael-oxidation: Efficient synthesis of flavones under mild reaction conditions
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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
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p. 6930 - 6933
(2011/11/04)
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- Synthesis of γ-benzopyranone by TfOH-promoted regioselective cyclization of o-alkynoylphenols
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Regioselective cyclization of o-alkynoylphenols forming γ-benzopyranones has been demonstrated. Trifluoromethanesulfonic acid (TfOH) induced 6-endo cyclization of o-alkynoylphenols without forming 5-exo cyclized benzofuranone derivatives to provide the corresponding γ-benzopyranones in high yields.
- Yoshida, Masahito,Fujino, Yuta,Doi, Takayuki
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p. 4526 - 4529
(2011/10/09)
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- Regioselective synthesis of flavone derivatives via DMAP-catalyzed cyclization of o-alkynoylphenols
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A catalytic amount of DMAP promoted cyclization of o-alkynoylphenols via a 6-endo cyclization mode leading to flavone derivatives in high yields without forming 5-exo cyclized aurone derivatives. Utilizing this method, methoxy substituted flavone and alkyl substituted γ-benzopyranone derivatives were synthesized.
- Yoshida, Masahito,Fujino, Yuta,Saito, Koya,Doi, Takayuki
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p. 9993 - 9997
(2012/02/06)
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- A convenient and safe O-methylation of flavonoids with dimethyl carbonate (DMC)
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Dietary flavonoids exhibit beneficial health effects. Several epidemiological studies have focused on their biological activities, including antioxidant, antibacterial, antiviral, anti-inflammatory and cardiovascular properties. More recently, these compounds have shown to be promising cancer chemopreventive agents in cell culture studies. In particular, O-methylated flavonoids exhibited a superior anticancer activity than the corresponding hydroxylated derivatives being more resistant to the hepatic metabolism and showing a higher intestinal absorption. In this communication we describe a convenient and efficient procedure in order to prepare a large panel of mono- and dimethylated flavonoids by using dimethyl carbonate (DMC), an ecofriendly and non toxic chemical, which plays the role of both solvent and reagent. In order to promote the methylation reaction under mild and practical conditions, 1,8-diazabicyclo[5.4.0]undec-7- ene (DBU) was added in the solution; methylated flavonoids were isolated in high yields and with a high degree of purity. This methylation protocol avoids the use of hazardous and high toxic reagents (diazomethane, dimethyl sulfate, methyl iodide).
- Bernini, Roberta,Crisante, Fernanda,Ginnasi, Maria Cristina
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experimental part
p. 1418 - 1425
(2011/04/25)
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- Selective and efficient oxidative modifications of flavonoids with 2-iodoxybenzoic acid (IBX)
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2-Iodoxybenzoic acid (IBX), a mild and efficient hypervalent iodine oxidant, has been utilised in different reaction conditions to perform several efficient oxidative modifications of flavonoids. Fine-tuning of the reaction conditions allowed remarkably selective modifications of these compounds. At room temperature, IBX proved to be an excellent reagent for a highly regioselective aromatic hydroxylation of monohydroxylated flavanones and flavones, generating the corresponding catecholic derivatives showing high antioxidant activity. At 90 °C, IBX efficiently dehydrogenated a large panel of methoxylated flavanones to their corresponding flavones exhibiting anticancer activity. IBX polystyrene has also been utilised to increase the recovery of highly polar compounds. Following the first oxidation, the reagent was recovered and reused in several runs without loss of efficiency and selectivity. The first example of an application of IBX polystyrene in a dehydrogenation reaction has been described.
- Barontini, Maurizio,Bernini, Roberta,Crisante, Fernanda,Fabrizi, Giancarlo
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experimental part
p. 6047 - 6053
(2010/09/11)
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- Sodium selenite-dimethylsulfoxide: a highly efficient reagent for dehydrogenation
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Sodium selenite in dimethylsulfoxide is a highly efficient reagent for dehydrogenation reactions and can be used under both thermal as well as microwave irradiation conditions. Using this reagent benzoins have been dehydrogenated to benzils, flavanones to flavones and 2'-hydroxy chalcones have been converted into flavones by cyclodehydrogenation.
- Lamba, Mandeep,Makrandi, Jagdish Kumar
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experimental part
p. 225 - 226
(2009/08/15)
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- Efficient synthesis of polyoxygenated flavones from naturally occurring flavanones
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Flavonoids are constituents of the human diet (they are present in many beverages and food), and in organisms they are responsible for several biological functions, including that of antioxidant. Because of the increasing interest in these molecules, methods for their synthesis and structural modification are of great importance; studies on the biological activities of many of these compounds are insufficient because of their scarcity and/or high cost. We have developed an expeditious synthesis of polyoxygenated flavones, starting from available and inexpensive flavanones, using a bromination- methoxylation procedure. A series of flavonoids that are not otherwise accessible can be prepared using this method. As an example, 3′-demethoxysudachitin, a limited flavone possessing antimicrobial activity against methicillin-resistant Staphylococcus aureus and Helicobacter pylori and acting as a 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenger, was prepared in fairly satisfactory yield.
- Bovicelli, Paolo,D'Angelo, Vittoria,Collalto, Daniela,Verzina, Antonio,D'Antona, Nicola,Lambusta, Daniela
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p. 1697 - 1701
(2008/03/11)
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- An environmentally benign synthesis of flavones from 1,3-diketones using silica gel supported NaHSO4 catalyst
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A simple and enviromentaly benign method for synthesis of flavones is described via dehydrative cyclisation of o-hydroxydibenzoylmethane using silica gel supported NaHSO4 catalyst.
- Kucukislamoglu, Mustafa,Nebioglu, Mehmet,Zengin, Mustafa,Arslan, Mustafa,Yayli, Nurettin
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p. 556 - 557
(2007/10/03)
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- Photohydrodimerization of 6-methoxyflavone to 6,6″-dimethoxy-2, 2″-biflavanones
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6-Methoxyflavone (7) easily afforded two hydrodimers of rac-6,6″-dimethoxy-2,2″-biflavanone (8a) and meso-6,6″- dimethoxy-2,2″-biflavanone (8b) and one reductive product of 6-methoxyflavanone (9) by using photolysis with the electron-donating amines including triethylamine, 2-(N,N-dimethylamino)ethanol or N,N-dimethylaniline in solvents of acetonitrile, benzene or methylene dichloride. They were found to give higher yields of rac-6,6″-dimethoxy-2,2″-biflavanone (8a) and meso-6,6″-dimethoxy-2,2″-biflavanone (8b) (38.7% and 4.5%, 35.3% and 6.2%, respectively) in the reaction conditions of 1/10 molar ratio of 6-methoxyflavone (7) to triethylamine in a solvent of acetonitrile with irradiation of twenty-four hours by using 306 nm and 352 nm lamps.
- Chen, Arh-Hwang,Kuo, Wei-Bao,Chen, Chia-Wen
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p. 1389 - 1394
(2007/10/03)
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- Substituted heterocyclic compounds, method for preparing and compositions containing same
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The invention relates to compounds of formula (I): wherein: R1, R2and R3are as defined in the description, X is as defined in the description, Y represents an oxygen atom, a sulphur atom, a C(H)qgroup, SO or SO2, n is equal to from 0 to 5, A represents a NR5R6group, and medicinal products containing the same which are useful in treating or in preventing melatoninergic disorders.
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- An Expeditious Synthesis of Flavones on Montmorillonite K 10 Clay with Microwaves
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A manipulatively simple and rapid method for the synthesis of flavones is described via a solid-state dehydrative cyclizatton of o-hydroxydibenzoylmethanes on a clay surface using microwaves.
- Varma, Rajender S.,Saini, Rajesh K.,Kumar, Dalip
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p. 348 - 349
(2007/10/03)
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