- 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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- Biocatalytic green alternative to existing hazardous reaction media: Synthesis of chalcone and flavone derivatives via the Claisen-Schmidt reaction at room temperature
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Owing to the increasing amount of waste materials around the globe, the conversion of waste or secondary by-products to value-added products for various applications has gained significant interest. Herein, two novel agro-food waste products, Musa sp. 'Malbhog' peel ash (MMPA) and Musa Champa Hort. ex Hook. F. peel ash (MCPA) are used as catalysts to promote an inexpensive, efficient and eco-friendly carbon-carbon bond forming crossed aldol reaction at room temperature in solvent free conditions. Furthermore, the resulting products were subjected to reactions with these promoters in an oxygen atmosphere and led to the formation of novel flavone derivatives. Moreover, the used catalysts were properly characterized using different sophisticated analytical techniques such as Fourier-transform infrared spectroscopy (FT-IR), X-ray diffractometry (XRD), Brunauer-Emmett-Teller analysis (BET), Raman spectroscopy, scanning electron microscopy energy dispersive X-ray spectroscopy (SEM-EDS), transition electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA) along with element detection using atomic absorption spectroscopy and ion chromatographic methods. These two approaches are metal free, as well as being devoid of any extra additives, co-catalysts, harsh conditions, the use of column chromatography for purification and result in a higher yield of the product within a short space of time. The catalytic abilities of the promoter were also examined to synthesize important bioactive molecules such as butein and apigenin at room temperature. With gram scale synthesis of the chalcone derivatives, the used catalysts (MMPA and MCPA) were further reused for five cycles and did not demonstrate any loss in catalytic activity.
- Tamuli, Kashyap J.,Sahoo, Ranjan K.,Bordoloi, Manobjyoti
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supporting information
p. 20956 - 20965
(2020/12/31)
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- Method for synthesizing 2-aryl benzopyrone flavonoid derivatives
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The invention relates to a method for synthesizing 2-aryl benzopyrone flavonoid derivatives, and relates to a method for synthesizing a compound, the method for synthesizing 2-aryl benzopyrone flavonoid derivatives is suitable for the synthesis of 2-aryl benzopyrone flavonoid derivatives containing different substituents. The method aims to solve the technical problems of low yield, long reactionperiod, and complicated post-treatment and high operation difficulty of the existing synthesis method of the ketone flavonoid derivative. The method comprises the following steps of: 1, preparing beta-propanedione compounds; 2, preparing flavonoid compound 2-aryl benzopyranones. The method completes esterification and rearrangement in one step, which is simple and practical, reduces intermediate links of reaction, saves separation and purification of intermediate products, improves utilization rate of raw materials, reduces reaction temperature, shortens reaction time under microwave radiation, reduces solvent consumption, the post-treatment is relatively simple, the yield is relatively high and no by-products exist, and can also react in the presence of a small amount of water, the reaction is easy to operate, and the method is suitable for industrial production. The method belongs to the technical field of compound synthesis.
- -
-
Paragraph 0070; 0073; 0074
(2019/04/30)
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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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- Synthesis, antiproliferative and pro-apoptotic effects of nitrostyrenes and related compounds in Burkitt’s lymphoma
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Background: Cancers of the lymphatic cells (lymphomas) account for approximately 12% of malignant diseases worldwide. The nitrostyrene scaffold is identified as a lead target structure for the development of particularly effective compounds targeting Burkitt’s lymphoma (BL). Objectives: The aims of the curent study were to synthesise a panel of nitrostyrene compounds and to evaluate their activity in Burkitt’s lymphoma (BL). Methods: A panel of structurally varied compounds were designed and synthesised using Henry Knoevenagel condensation reactions. Single crystal X-Ray analysis confirmed the E configuration for six examples of these novel structures. A number of nitrostyrene-related compounds were also investigated including 1,3-bis(aryl)-2-nitropropenes together with heterocyclic scaffolds containing the nitrovinyl pharmacophore such as 3-nitro-2-phenyl-2H-chromenes. The antiproliferative activities of the compounds were evaluated using the BL cell lines EBV- MUTU-1 and EBV+ DG-75 (chemoresistant) to establish preliminary structure-activity relationships. Results: Lead compounds with optimized nitrostyrene scaffolds and 3-nitro-2-phenyl-2Hchromene structures were successfully established with typical IC50 values of 0.45 μM and 0.47 μM in MUTU-1 cells and 1.41 μM and 1.92 μM, respectively, in DG-75 cells. The mechanism of cell death was identified as apoptotic and the lead compound was found to elicit comparable apoptotic effects to Taxol in Burkitt’s lymphoma cell lines MUTU-1 and DG-75. Conclusion: This class of pharmaceutically active compounds with potential for the treatment of Burkitt’s lymphoma suggest a potential role for nitrostyrene based agents in chemotherapy.
- Byrne, Andrew J.,Bright, Sandra A.,Fayne, Darren,McKeown, James P.,McCabe, Thomas,Twamley, Brendan,Williams, Clive,Meegan, Mary J.
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p. 181 - 199
(2018/03/13)
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- 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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- 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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- One Pot Synthesis of γ-Benzopyranones via Iron-Catalyzed Aerobic Oxidation and Subsequent 4-Dimethylaminopyridine Catalyzed 6-endo Cyclization
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One-pot synthesis of γ-benzopyranones was realized in decent yields and excellent regioselectivities via iron-catalyzed aerobic oxidation and 4-dimethylaminopyridine-catalyzed cyclization of related propargylic alcohols. Derivatizations to aromatic substituted γ-benzopyranones and synthesis of naturally occurring 3′,4′-dimethoxyflavone have also been realized. (Figure presented.).
- Zhai, Di,Chen, Lingzhu,Jia, Minqiang,Ma, Shengming
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p. 153 - 160
(2017/11/23)
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- One-Pot Allan–Robinson/Friedl?nder Route to Chromen-/Quinolin-4-ones through the Domino Acetylative Cyclisation of 2-Hydroxy-/2-Aminobenzaldehydes
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The domino synthesis of 2-phenyl-4H-chromen-4-ones and quinolin-4-ones through acetylation of 2-hydroxy-/2-aminobenzaldehydes with α-haloketones followed by intramolecular oxa-/azaheterocyclisation is reported. This method represents a new extension of the Allan–Robinson and Friedl?nder reactions, and uses N-heterocyclic-carbene catalysis to construct the target molecules in good to excellent yields: 86–95 % for the chromen-4-ones, and 83–96 % for the quinolin-4-ones. This approach has the advantages of operational simplicity, ambient reaction conditions, and no by-product formation.
- Rai, Vijai K.,Verma, Fooleswar,Sahu, Ganeshwar P.,Singh, Manorama,Rai, Ankita
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p. 537 - 544
(2018/02/09)
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- 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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- Metal-free oxidative nitration of α-carbon of carbonyls leads to one-pot synthesis of thiohydroximic acids from acetophenones
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A metal-free nitration of the α-C-H to carbonyl in propiophenones was achieved with I2/NaNO2 in the presence of an oxidant in dimethyl sulfoxide (DMSO) as the medium. Conversely under similar conditions, reaction of acetophenones produced thiohydroximic acids via a radical-based cascade event which involves oxidative nitration of the α-carbon to a carbonyl followed by Michael addition of the thiomethyl group from DMSO and subsequent rearrangement. Besides DMSO, the scope of the reaction encompasses other symmetrical and unsymmetrical dialkylsulfoxides.
- Dighe, Shashikant U.,Mukhopadhyay, Sushobhan,Priyanka, Kumari,Batra, Sanjay
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supporting information
p. 4190 - 4193
(2016/09/09)
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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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- A 7 - methoxy flavone preparation method (by machine translation)
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The invention discloses a 7 - methoxy flavone preparation method, which belongs to the field of chemical synthesis, the method comprising: in order to Paeonia suffruticosa Andr. (tree peony bark) phenol and benzoyl chloride as the raw material, in the presence of triethylamine base to carry out the esterification reaction, the reaction mixture after the reaction is finished by carrying out simple suction filtering to eliminate triethylamine hydrochloride, potassium tertiary butanol filtrate directly the reaction at room temperature, after the reaction is finished adding dibutyl tin oxide and to the reaction mixture liquid to heating reflux dehydration, to obtain 7 - methoxy flavone. The technical route has the route is short, simple and convenient operation, pollution-free, the dehydrating agent can be used in circulation, and easy for industrial production characteristics, is a very economic, simple preparation of 7 - methoxy flavone method. (by machine translation)
- -
-
Paragraph 0030; 0031
(2017/02/02)
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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.
- -
-
Paragraph 0100; 0101; 0102
(2016/10/08)
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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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- 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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- A versatile approach to flavones via a one-pot Pd(II)-catalyzed dehydrogenation/oxidative boron-Heck coupling sequence of chromanones
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A variety of flavones were expediently synthesized from readily accessible chromanones via a one-pot sequence involving Pd(ii)-catalyzed dehydrogenation and oxidative boron-Heck coupling with arylboronic acid pinacol esters. In particular, the use of arylboronic acid pinacol esters was found to significantly improve the yield of the reaction.
- Lee, Jun,Yu, Jihyun,Son, Seung Hwan,Heo, Jinyuk,Kim, Taelim,An, Ji-Young,Inn, Kyung-Soo,Kim, Nam-Jung
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p. 777 - 784
(2016/01/12)
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- Pd(OAc)2/S=PPh3 accelerated activation of gem-dichloroalkenes for the construction of 3-arylchromones
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The Pd-catalyzed regioselective intramolecular nucleophilic substitution of gem-dichloroalkene derivatives with salicylaldehydes leading to the synthesis of 3-arylchromones has been developed. Pd(OAc)2/S=PPh3 could activate gem-dichloroalkenes and undergo nucleophilic substitution by salicylaldehydes with the aid of a base.
- Liu, Jianming,Song, Weiwei,Yue, Yuanyuan,Liu, Ren,Yi, Hong,Zhuo, Kelei,Lei, Aiwen
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supporting information
p. 17576 - 17579
(2015/12/08)
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- Gold Nanoparticles Supported on a Layered Double Hydroxide as Efficient Catalysts for the One-Pot Synthesis of Flavones
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Flavones are a class of natural products with diverse biological activities and have frequently been synthesized by step-by-step procedures using stoichiometric amounts of reagents. Herein, a catalytic one-pot procedure for the synthesis of flavone and its derivatives is developed. In the presence of gold nanoparticles supported on a Mg-Al layered double hydroxide (Au/LDH), various kinds of flavones can be synthesized starting from 2′-hydroxyacetophenones and benzaldehydes (or benzyl alcohols). The present one-pot procedure consists of a sequence of several reactions, and Au/LDH can catalyze all these different types of reactions. The catalysis is shown to be truly heterogeneous, and Au/LDH can be readily recovered and reused. Go for gold: In the presence of gold nanoparticles supported on a Mg-Al layered double hydroxide (Au/LDH), various flavones were obtained from the corresponding 2′-hydroxyacetophenones and benzaldehydes (or benzyl alcohols). All three (four) steps of this one-pot process are catalyzed by Au/LDH in a truly heterogeneous fashion.
- Yatabe, Takafumi,Jin, Xiongjie,Yamaguchi, Kazuya,Mizuno, Noritaka
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supporting information
p. 13302 - 13306
(2015/11/09)
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- Single and double intramolecular proton transfers in the electronically excited state of flavone derivatives
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In an attempt to create a flavone derivative able to take part in Excited State Intramolecular Double Proton Transfer (ESIDPT), we synthesized two carbonyl derivatives of 3,7-dihydroxyflavone, both containing two different proton-transfer sites as well as related carbonyl derivatives of 3-hydroxyflavone and 7-hydroxyflavone. All the examined hydroxyflavones were found to participate in the Excited State Intramolecular Proton Transfer (ESIPT). ESIPT which involves 3-hydroxyl and 4-carbonyl groups was found to have a higher barrier compared to ESIPT involving 7-hydroxyl and 6/8-carbonyl fragments. According to the data presented, 3,7-dihydroxy-2-phenyl-6-(3-phenylpropanoyl)-4H-chromen-4-one undergoes a two-stage ESIDPT with formation of an intermediate tautomer. This kind of ESIDPT leads to a tautomeric form with an abnormally low rate of radiative deactivation of the excited state, which conditions low fluorescence quantum yield. The behavior of 3,7-dihydroxy-4-oxo-2-phenyl-4H-chromene-8-carbaldehyde in the electronically excited state is similar to 3-hydroxyflavone derivatives, thus we conclude the occurrence of a single ESIPT in this compound.
- Serdiuk,Roshal
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p. 102191 - 102203
(2015/12/11)
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- Steroid Sulfatase Inhibitors Based on Phosphate and Thiophosphate Flavone Analogs
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Preclinical Research A series of phosphate and thiophosphate flavone derivatives were synthesized and biologically evaluated in vitro for inhibition of steroid sulfatase (STS) activity. The described synthesis includes the straightforward preparation of 7-hydroxy-2-phenyl-4H-chromen-4-one 3a, 2-(4-fluorophenyl)-7-hydroxy-4H-chromen-4-one 3b, 7-hydroxy-2-(4-(trifluoromethyl)phenyl)-4H-chromen-4-one 3c, 7-hydroxy-2-(p-tolyl)-4H-chromen-4-one 3d modified with different phosphate or thiophosphate moieties. The inhibitory properties of the synthesized compounds were tested against human placenta STS. Some of the novel STS inhibitors had good activities against STS. In particular, the bis-(4-oxo-2-(p-tolyl)-4H-chromen-7-yl) hydrogenthiophosphate, 6i had the most potent inhibitory effect with an IC50 value of 3.25 μM as compared to an IC50 value of 8.50 μM for the 2-(4-trifluoromethylphenyl)-chromen-4-one-7-O-sulfamate used as a reference. Drug Dev Res 76: 450-462, 2015.
- Kozak, Witold,Dako, Mateusz,Maslyk, Maciej,Kubiski, Konrad,Rachon, Janusz,Demkowicz, Sebastian
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p. 450 - 462
(2016/01/28)
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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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- Pyrrolidine and iodine catalyzed domino aldol-Michael-dehydrogenative synthesis of flavones
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A one pot synthesis of flavones is established from 2′- hydroxyacetophenones and substituted aromatic aldehydes. The method uses domino aldol-Michael-oxidation reaction catalyzed by pyrrolidine as a base and iodine as an oxidant in dimethyl sulfoxide.
- Naik, Mayuri M.,Tilve, Santosh G.,Kamat, Vijayendra P.
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p. 3340 - 3343
(2014/06/09)
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- 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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- 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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- 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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- Assessment of antiplatelet activity of 2-aminopyrimidines
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A series of 4,6-diaryl-2-aminopyrimidines was developed as antiplatelet agents and their potency was evaluated by in vitro assay. Compound 14k was found to be two times more potent than aspirin. These encouraging results could be helpful for the development of new antiplatelet compounds.
- Giridhar, Rajani,Tamboli, Riyaj S.,Ramajayam,Prajapati, Dhaval G.,Yadav
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scheme or table
p. 428 - 432
(2012/07/03)
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- A concise synthesis of 3-aroylflavones via Lewis base 9-azajulolidine- catalyzed tandem acyl transfer-cyclization
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Lewis base-catalyzed tandem acyl transfer-cyclization of acylated o-alkynoylphenols leading to 3-aroylflavones was developed. 9-Azajulolidine smoothly promoted the reaction of the aroyl derivatives at ambient temperature, and the structure-diversed synthesis of 3-aroylflavones with distinct substituents was achieved in moderate to excellent yields.
- Yoshida, Masahito,Saito, Koya,Fujino, Yuta,Doi, Takayuki
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p. 11796 - 11798,3
(2020/10/15)
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- Palladium-catalyzed dehydrogenation/oxidative cross-coupling sequence of β-heteroatom-substituted ketones
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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
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supporting information
p. 11333 - 11336,4
(2012/12/12)
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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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- Palladium-catalyzed carbonylation reaction of aryl bromides with 2-hydroxyacetophenones to form flavones
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Flavone of the month: A general and efficient method for the palladium-catalyzed carbonylative synthesis of flavones has been developed (see scheme). Starting from aryl bromides and 2-hydroxyacetophenones, the corresponding flavones have been isolated in good yields. Copyright
- Wu, Xiao-Feng,Neumann, Helfried,Beller, Matthias
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supporting information
p. 12595 - 12598
(2012/11/07)
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- Synthetic approach to flavanones and flavones via ligand-free palladium(ii)-catalyzed conjugate addition of arylboronic acids to chromones
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The remarkable catalytic effects of Fe(OTf)3 in the context of the Pd(ii)-catalyzed conjugate addition of arylboronic acids to chromones were observed to yield a variety of flavanones under mild conditions. The addition of catalytic amounts of DDQ and KNO2 to the reactions exclusively yielded flavone analogs. The reaction scope for the transformation was fairly broad, affording good yields of a wide range of flavanones and flavones, which are privileged structures in many biologically active compounds.
- Kim, Donghee,Ham, Kyungrok,Hong, Sungwoo
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experimental part
p. 7305 - 7312
(2012/09/22)
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- A facile route to flavone and neoflavone backbones via a regioselective palladium catalyzed oxidative Heck reaction
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A straightforward and atom-economical base-free palladium-catalyzed regioselective direct arylation of coumarins and chromenones is devised. This protocol is compatible with a wide variety of electron-donating and -withdrawing substituents and allows construction of various biologically important flavone and neoflavone backbones.
- Khoobi, Mehdi,Alipour, Masoumeh,Zarei, Samaneh,Jafarpour, Farnaz,Shafiee, Abbas
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p. 2985 - 2987
(2012/04/04)
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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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- Oxidative cyclisation of 2′-hydroxychalcones using sodium tellurite: Synthesis of flavones
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A simple and very efficient method for the oxidative cyclisation of 2′-hydroxychalcones with sodium tellurite in dimethylsulphoxide has been developed which could provide a simple route for the synthesis of flavones and also the required compound obtained as the sole product in a very high yield.
- Kumar, Surender,Sharma, Dinesh
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experimental part
p. 761 - 763
(2012/04/04)
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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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- A new series of flavones, thioflavones, and flavanones as selective monoamine oxidase-B inhibitors
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A new series of synthetic flavones, thioflavones, and flavanones has been synthesized and evaluated as potential inhibitors of monoamine oxidase isoforms (MAO-A and -B). The most active series is the flavanone one with higher selective inhibitory activity against MAO-B. Some of these flavanones (mainly the most effective) have been separated and tested as single enantiomers. In order to investigate the MAOs recognition of the most active and selective compounds, a molecular modeling study has been performed using available Protein Data Bank (PDB) structures as receptor models for docking experiments.
- Chimenti, Franco,Fioravanti, Rossella,Bolasco, Adriana,Chimenti, Paola,Secci, Daniela,Rossi, Francesca,Yá?ez, Matilde,Orallo, Francisco,Ortuso, Francesco,Alcaro, Stefano,Cirilli, Roberto,Ferretti, Rosella,Sanna, M. Luisa
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experimental part
p. 1273 - 1279
(2010/04/24)
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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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- Enantioselective synthesis of chromanes by iridium-catalyzed asymmetric hydrogenation of 4H-chromenes
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Iridium complexes of chiral oxazoline-based P,N-ligands proved to be efficient catalysts for the enantioselective hydrogenation of 2-aryl- and 2-alkyl-4H-chromenes. The best results were obtained with a ligand derived from threonine (ThrePHOX), which induced ee values of 95% to >99% in the hydrogenation of 2-methyl-, 2-cyclohexyl- and various 2-aryl-substituted chromenes. Georg Thieme Verlag Stuttgart.
- Valla, Carine,Baeza, Alejandro,Menges, Frederik,Pfaltz, Andreas
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scheme or table
p. 3167 - 3171
(2009/06/17)
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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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- Microbial metabolism. Part 6. Metabolites of 3- and 7-hydroxyflavones
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Fermentation of 3-hydroxyflavone (1) with Beauveria bassiana (ATCC 13144) yielded 3,4′-dihdroxyflavone (3), flavone 3-O-β-D-4-O- methylglucopyranoside (4) and two minor metabolites. 7-Hydroxyflavone (2) was transformed by Nocardia species (NRRL 5646) to 7-methoxyflavone (5) whilst Aspergillus alliaceus (ATCC 10060) converted it to 4′,7-dihydroxyflavone (6). Flavone 7-O-β-D-4-O-metylglucopyranoside (7) and 4′- hydroxyflavone 7-O-β-D-4-O-methylglucopyranoside (8) were the metabolic products of 7-hydroxyflavone (2) when fermented with Beauveria bassiana (ATCC 7159). One of the minor metabolites of 3-hydroxyflavone (1) was tentatively assigned a β′-chalcanol structure (9). Compounds 4, 7 and 8 are reported as new compounds. Structure elucidation of the metabolites was based on spectroscopic data.
- Herath, Wimal,Mikell, Julie Rakel,Hale, Amber Lynn,Ferreira, Daneel,Khan, Ikhlas Ahmad
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p. 320 - 324
(2007/10/03)
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- A selective transformation of flavanones to 3-bromoflavones and flavones under microwave irradiation
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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
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- Transcription factor modulating compounds and methods of use thereof
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Substituted benzoimidazole compounds useful as anti-infectives that decrease resistance, virulence, or growth of microbes are provided. Methods of making and using substituted benzoimidazole compounds, as well as pharmaceutical preparations thereof, in, e.g., reducing antibiotic resistance and inhibiting biofilms.
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Page/Page column 75
(2008/06/13)
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- Transcription factor modulating compounds and methods of use thereof
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Substituted benzoimidazole compounds useful as anti-infectives that decrease resistance, virulence, or growth of microbes are provided. Methods of making and using substituted benzoimidazole compounds, as well as pharmaceutical preparations thereof, in, e.g., reducing antibiotic resistance and inhibiting biofilms.
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- Formation of the unexpected 3-alkylated flavonoids in the alkylation of B-ring substituted 5,7-dihydroxy flavones
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Treatment of B-ring substituted 5,7-dihydroxy flavones with alkyl halides in the presence of potassium carbonate gave unexpected 3-alkylated flavonoids. Related experiments were carried out to explain the formation of 3-alkylated flavonoids and a ring opening followed by alkylation and ring closure mechanism was proposed.
- Wang, Cai-Ling,Zheng, Xing,Meng, Wei-Dong,Li, Hong-Qi,Qing, Feng-Ling
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p. 5399 - 5402
(2007/10/03)
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