- Saccharin as an organocatalyst for quinoxalines and pyrido[2,3-b[pyrazines Syntheses
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A room-temperature procedure using saccharin as catalyst has been described for the cyclocondensation of different 1,2-arylenediamines with various 1,2-dicarbonyl compounds, yielding either quinoxalines or pyrido[2,3-b] pyrazines. The reactions proceed in very short reaction times in methanol, and the target heterocycles are isolated in quantitative yields after addition of water, filtration, and drying. Substituted pyrido[2,3-b]pyrazines can also be reached regioselectively by reacting α-ketoaldehydes with 2,3-diaminopyridine. Taylor and Francis Group, LLC.
- Lassagne, Frederic,Chevallier, Floris,Mongin, Florence
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- Gold-catalyzed synthesis of glyoxals by oxidation of terminal alkynes: One-pot synthesis of quinoxalines
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From terminal alkynes to glyoxals: Terminal alkynes can be oxidized under mild conditions by the use of an N-oxide in the presence of a gold catalyst. The intermediate glyoxal derivatives can be transferred in a one-pot procedure to substituted quinoxalines (see scheme). Copyright
- Shi, Shuai,Wang, Tao,Yang, Weibo,Rudolph, Matthias,Hashmi, A. Stephen K.
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- Efficient and inexpensive synthesis of benzimidazoles and quinoxalines
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o-Phenylenediamines were reacted with carbonyl compounds, β-ketoesters, and 1,2-diketones in presence of ammonium salts to give benzimidazoles and quinoxalines in very good yields. Ammonium salts are commercial and environmentally benign catalysts. Copyright Taylor & Francis Group, LLC.
- Raju, B. China,Theja, N. Dharma,Kumar, J. Ashok
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- Hypervalent iodine(iii) sulfonate mediated synthesis of quinoxalines in liquid peg-400
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PEG-400[poly(ethylene glycol-400)] is used as a "green" recyclable solvent in the one-pot synthesis of quinoxalines by reaction with aryl ketones, hypervalent Iodine(III) Sulfonate, and o-phenylenediamines. Significant rate enhancements and improved yields have been observed.
- Lin, Pei-Ying,Hou, Rei-Sheu,Wang, Huey-Min,Kang, Iou-Jiun,Chen, Ling-Ching
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- Efficient and green synthesis of 1,2-disubstituted benzimidazoles and quinoxalines using bronsted acid ionic liquid, [(CH2) 4SO3HMIM][HSO4], in water at room temperature
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1,2-Disubstituted benzimidazoles and quinoxalines have been synthesized in the presence of Brnsted acid ionic liquid, [(CH2)4SO 3HMIM][HSO4], in water at ambient temperature.
- Beheshtiha, Yahya S.,Heravi, Majid M.,Saeedi, Mina,Karimi, Narges,Zakeri, Masumeh,Tavakoli-Hossieni, Niloofar
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- Molecular iodine: A powerful catalyst for the easy and efficient synthesis of quinoxalines
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Various biologically important quinoxaline derivatives were efficiently synthesized in excellent yields using inexpensive, nontoxic, and readily available bench top chemical, iodine in catalytic amount (10 mol %). Besides this, a systematic study was carried out to evaluate parameters such as solvent and catalyst loading. Several aromatic as well as aliphatic 1,2-diketones and aromatic 1,2-diamines, such as substituted phenylene diamines, tetra amines were further subjected to condensation using catalytic amounts of iodine to afford the products in excellent yield.
- More, Shivaji V.,Sastry,Wang, Chieh-Chieh,Yao, Ching-Fa
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- Zirconium tetrakis(dodecyl sulfate) [Zr(DS)4] as an efficient lewis acid-surfactant combined catalyst for the synthesis of quinoxaline derivatives in aqueous media
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Zirconium tetrakis(dodecyl sulfate) [Zr(DS)4] efficiently catalyzes the synthesis of quinoxaline derivatives via the condensation of 1,2-diamines with 1,2-diketones in H2O as a green media at room temperature. Using this method, the title compounds are produced in good to excellent yields and relatively short reaction times. Copyright Taylor & Francis Group, LLC.
- Hasaninejad, Alireza,Zare, Abdolkarim,Zolfigol, Mohammad Ali,Shekouhy, Mohsen
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- A rapid synthesis of quinoxalines starting from ketones
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A fast and general synthesis of quinoxalines, performed in two stages or as a one-pot reaction, starting from ketones via their α-hydroxylimino ketone derivatives, and condensation of the latter with 1,2-diaminobenzene under microwave irradiation, is described.
- Padmavathy,Nagendrappa, Gopalpur,Geetha
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- Synthesis and application of polyvinylimidazole-based Br?nsted acidic ionic liquid grafted silica as an efficient heterogeneous catalyst in the preparation of quinoxaline derivatives
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Two types of polymer-grafted silica based on polyvinylimidazole Br?nsted acidic ionic liquids were prepared and used as new heterogeneous catalysts for the preparation of pharmaceutically important quinoxaline derivatives. These catalysts were characterized by thermogravimetric analysis, FT-IR spectroscopy, and titration. They could be recycled without considerable loss in their catalytic activity. High efficiency of the catalysts along with short reaction times, high yields, easy purification, recyclability, and simple procedure are among the advantages of these catalytic systems.
- Tamami, Bahman,Sardarian, Alireza,Ataollahi, Elaheh
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- Efficient and green method for the synthesis of 1,5-benzodiazepine and quinoxaline derivatives in water
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Various 1,5-benzodiazepine and quinoxaline derivatives have been synthesized in water with excellent yields using a catalytic amount of indium chloride at room temperature. This synthetic protocol is nontoxic, safe, and environmentally benign. Copyright T
- Hazarika, Parasa,Gogoi, Pranjal,Konwar, Dilip
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- Ligand-Tuneable, Red-Emitting Iridium(III) Complexes for Efficient Triplet–Triplet Annihilation Upconversion Performance
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A series of substituted 2-phenylquinoxaline ligands have been explored to finely tune the visible emission properties of a corresponding set of cationic, cyclometallated iridium(III) complexes. The electronic and redox properties of the complexes were investigated through experimental (including time-resolved luminescence and transient absorption spectroscopy) and theoretical methods. The complexes display absorption and phosphorescent emissions in the visible region that are attributed to metal to ligand charge-transfer transitions. The different substitution patterns of the ligands induce variations in these parameters. Time-dependent DFT studies support these assignments and show that there is likely to be a strong spin-forbidden contribution to the visible absorption bands at λ=500–600 nm. Calculations also reliably predict the magnitude and trends in triplet emitting wavelengths for the series of complexes. The complexes were assessed as potential sensitisers in triplet–triplet annihilation upconversion experiments by using 9,10-diphenylanthracene as the acceptor; the methylated variants performed especially well with impressive upconversion quantum yields of up to 39.3 %.
- Phillips, Kaitlin A.,Stonelake, Thomas M.,Chen, Kepeng,Hou, Yuqi,Zhao, Jianzhang,Coles, Simon J.,Horton, Peter N.,Keane, Shannon J.,Stokes, Emily C.,Fallis, Ian A.,Hallett, Andrew J.,O'Kell, Sean P.,Beames, Joseph M.,Pope, Simon J. A.
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- Efficient, ecofriendly, and practical process for the synthesis of quinoxalines catalyzed by amberlyst-15 in aqueous media
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Amberlyst-15/H2O has been used as an efficient and environmentally friendly catalytic system for the synthesis of quinoxalines. The present methodology offers several advantages, such as excellent yields, short reaction time, and simple workup. Copyright Taylor & Francis Group, LLC.
- Liu, Ju-Yan,Liu, Jing,Wang, Jia-Di,Jiao, De-Quan,Liu, Hai-Wang
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- An effective microwave-induced iodine-catalyzed method for the synthesis of quinoxalines via condensation of 1,2-diamines with 1,2-dicarbonyl compounds
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A microwave-induced iodine-catalyzed simple, rapid and convenient synthesis of different types of quinoxalines via condensation of 1,2-diamines with 1,2-dicarbonyl compounds has been accomplished with an excellent yield.
- Bandyopadhyay, Debasish,Mukherjee, Sanghamitra,Rodriguez, Robert R.,Banik, Bimal K.
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- A Combined Experimental and Theoretical Study of the Ammonium Bifluoride Catalyzed Regioselective Synthesis of Quinoxalines and Pyrido[2,3- b ]pyrazines
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Ammonium bifluoride was efficiently used at a 0.5 mol% loading to catalyze the cyclocondensation of 1,2-arylenediamines with 1,2-dicarbonyl compounds at room temperature in methanol-water to give quinoxalines or pyrido[2,3-b]pyrazines in excellent yields. Importantly, 2,8-disubstituted quinoxalines and 3-substituted pyrido[2,3-b]pyrazines were regioselectively formed by the reaction of arylglyoxals with 3-methylbenzene-1,2-diamine or pyridine-2,3-diamine, respectively. An analysis of the density functional theory reactivity indices explained the catalytic role of ammonium bifluoride.
- Lassagne, Frédéric,Chevallier, Floris,Roisnel, Thierry,Dorcet, Vincent,Mongin, Florence,Domingo, Luis R.
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- Ketones as a new synthon for quinoxaline synthesis
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o-Phenylenediamines react with an array of ketones in PEG-400 at 60 °C under an atmosphere of air in the presence of KOH to afford the corresponding quinoxalines in good yields.
- Cho, Chan Sik,Ren, Wen Xiu,Shim, Sang Chul
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- Nitrilotris(Methylenephosphonic Acid) as a New Highly Efficient and Recyclable Br?Nested Acid Catalyst for the Synthesis of Quinoxaline Derivatives under Mild and Green Conditions
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Nitrilotris(methylenephosphonic acid) has been introduced as a novel organocatalyst for the preparation of quinoxalines. It can efficiently catalyze the synthesis of quinoxaline derivatives from 1,2-diamines and 1,2-diketones under mild, efficient, and eco-friendly conditions. Excellent yields, very short reaction times, safety, and recyclability of the catalyst system are other features of the proposed method.
- Fathi, Safoura,Sardarian, Ali Reza
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- Radical chain reactions of α-azido ketones with tributyltin hydride: Reduction vs nitrogen insertion and 1,2-hydrogen shift in the intermediate N-stannylaminyl radicals
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The radical chain reactions of a variety of acyclic and cyclic α-azido ketones with tributyltin hydride have been investigated. The derived N-(tributylstannyl)aminyl radicals normally undergo H-abstraction reaction yielding corresponding amines, and thence symmetrical pyrazines by subsequent self-condensation, in competition with 1,2-H-migration from the α-carbon to nitrogen leading to α-imino ketone decomposition products with loss of the chain-carrying tributyltin radical. The noteworthy occurrence of a quite uncommon radical 1,2-hydrogen-atom shift is considered to be largely due to consequent formation of a highly stable, captodative carbon-centred radical. In contrast with our previous N-stannylaminyl radicals produced from α-azido-β-keto esters, the present aminyl congeners give poor amounts (or even none) of nitrogen-inserted amides/lactams, which are envisaged to arise from intramolecular three-membered cyclisation onto the ketone moiety followed by β-scission of the resultant alkoxyl radical. It is inferred that adequate stabilisation of the eventual ring-opened carbon radical be a major factor for the successful outcome of the regiospecific nitrogen insertion process. Evidence is also presented that chemoselective attack of tris(trimethylsilyl)silyl radical to the ketone oxygen of an α-azido ketone gives rise to deazidation as a likely consequence of β-elimination of azidyl radical by the ensuing α-silyloxyalkyl radical. X-Ray crystal structure analyses of the bromo ketone 5a, the azido ketone 5b, the caprolactam 22, and the pyrazine 26 have been performed.
- Benati, Luisa,Leardini, Rino,Minozzi, Matteo,Nanni, Daniele,Spagnolo, Piero,Strazzari, Samantha,Zanardi, Giuseppe,Calestani, Gianluca
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- Oxidative Sulfonylation of Hydrazones Enabled by Synergistic Copper/Silver Catalysis
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A copper/silver-cocatalyzed protocol for oxidative sulfonylation of hydrazones is demonstrated. A wide range of β-ketosulfones and N-acylsulfonamides are directly synthesized in moderate to good yields. Our work provides a viable method for scalable preparation of β-ketosulfone derivatives that have found wide applications in the pharmaceutical industry.
- Xu, Jun,Shen, Chao,Qin, Xian,Wu, Jie,Zhang, Pengfei,Liu, Xiaogang
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p. 3706 - 3720
(2021/02/05)
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- Iron(II)-Catalyzed Aerobic Biomimetic Oxidation of N-Heterocycles
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Herein, an iron(II)-catalyzed biomimetic oxidation of N-heterocycles under aerobic conditions is described. The dehydrogenation process, involving several electron-transfer steps, is inspired by oxidations occurring in the respiratory chain. An environmentally friendly and inexpensive iron catalyst together with a hydroquinone/cobalt Schiff base hybrid catalyst as electron-transfer mediator were used for the substrate-selective dehydrogenation reaction of various N-heterocycles. The method shows a broad substrate scope and delivers important heterocycles in good-to-excellent yields.
- Manna, Srimanta,Kong, Wei-Jun,B?ckvall, Jan-E.
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supporting information
p. 13725 - 13729
(2021/09/08)
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- Versatile Heteroleptic Cu(I) Complexes Based on Quino(xa)-line-Triazole Ligands: from Visible-Light Absorption and Cooperativity to Luminescence and Photoredox Catalysis
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Four new heteroleptic Cu(I) complexes based on 1, 2, 3-triazolyl-quinoline or quinoxaline and a chelating diphosphine were prepared and fully characterised. The mononuclear derivatives absorb in the visible region, up to 600 nm, while the dinuclear complex has a long-tail absorption up to 800 nm, showing an additional electronic state corroborated by theoretical calculations. Although a methylene group between the triazole and the quino(xa)line moiety increases the bite angle and decreases the luminescence in solution, all complexes emit brightly in the solid-state. Their redox properties in the excited state were determined, proving their ability in serving as photoredox catalysts in atom transfer radical addition successfully.
- Bruschi, Cecilia,Gui, Xin,Salaeh-arae, Nasrin,Barchi, Tobia,Fuhr, Olaf,Lebedkin, Sergei,Klopper, Wim,Bizzarri, Claudia
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p. 4074 - 4084
(2021/08/27)
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- NH2OH-HCl-Mediated Umpolung α-Methylsulfonylation of α-Sulfonyl Ketones with Methylsulfoxides: Synthesis of α,β-Bis-sulfonyl Arylketones
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In this paper, a novel and efficient route for the synthesis of α,β-bis-sulfonyl arylketones via an NH2OH-HCl-mediated intermolecular umpolung α-methylsulfonylation of α-sulfonyl ketones with methylsulfoxides is described. A plausible mechanism is proposed and discussed. Various reaction conditions for this efficient, one-pot, environmentally friendly transformation were investigated.
- Chang, Meng-Yang,Chen, Han-Yu,Tsai, Yu-Lin
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p. 1832 - 1836
(2019/03/07)
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- Discovery of 3-arylquinoxaline derivatives as potential anti-dengue virus agents
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We designed and synthesized a series of novel 3-arylquinoxaline derivatives and evaluated their biological activities as potential dengue virus (DENV) replication inhibitors. Among them, [3-(4-methoxyphenyl)quinoxalin-2-yl](phenyl)methanol (19a), [6,7-dic
- Tseng, Chih-Hua,Han, Cheng-Ruei,Tang, Kai-Wei
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- Halogen-bonded iodonium ion catalysis: A route to α-hydroxy ketones: Via domino oxidations of secondary alcohols and aliphatic C-H bonds with high selectivity and control
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A domino synthesis of α-hydroxy ketones has been developed from benzylic secondary alcohols employing catalytic iodonium ions stabilized by DMSO. The reaction proceeds through an unprecedented sequential oxidation of alcohols to ketone and its α-hydroxylation in a controlled manner. The spectroscopic evidence establishes the possibility of formation of a stable halogen-bonded adduct between DMSO and iodonium ions.
- Guha, Somraj,Kazi, Imran,Mukherjee, Pranamita,Sekar, Govindasamy
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p. 10942 - 10945
(2017/10/13)
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- Copper-Catalyzed Cascade Cycloamination of α-Csp3-H Bond of N-Aryl Ketimines with Azides: Access to Quinoxalines
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A copper-catalyzed cycloamination of α-Csp3-H bond of N-aryl ketimines with sodium azide has been developed. This methodology provides an efficient access to quinoxalines and features mild reaction conditions and readily available ketimines with diverse functional group tolerance.
- Chen, Tengfei,Chen, Xun,Wei, Jun,Lin, Dongen,Xie, Ying,Zeng, Wei
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p. 2078 - 2081
(2016/06/01)
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- Metal free C-H functionalization of diazines and related heteroarenes with organoboron species and its application in the synthesis of a CDK inhibitor, meriolin 1
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Here, we report a metal-free cross-coupling reaction of diazines and related heteroarenes with organoboron species via C-H functionalization. The optimized conditions represent a metal-free method for the activation of aryl/heteroarylboronic acids, which undergo coupling with diazines and related heteroarenes. Optimized conditions also find application in the synthesis of a pyrimidine-based potent CDK inhibitor, meriolin1.
- Thatikonda, Thanusha,Singh, Umed,Ambala, Srinivas,Vishwakarma, Ram A.,Singh, Parvinder Pal
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p. 4312 - 4320
(2016/05/24)
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- Investigation and Application of Amphoteric α-Amino Aldehyde: An in Situ Generated Species Based on Heyns Rearrangement
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In situ generation of the reactive amphoteric α-amino aldehyde with simple α-hydroxy ketones and phenylamine via Heyns rearrangement was proven to be feasible. Metal-free domino reactions based on this reactive intermediate were effectively used to afford important N-heterocycles including polysubstituted pyrroles, indoles, and quinoxalines conveniently. A simple starting material, water as the only byproduct, and diversity of the useful products will make this method greatly attractive for pharmaceutics.
- Li, Guangxun,Tang, Ling,Liu, Hongxin,Wang, Yingwei,Zhao, Gang,Tang, Zhuo
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p. 4526 - 4529
(2016/09/28)
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- One-step approach for the synthesis of functionalized quinoxalines mediated by T3P-DMSO or T3P: Via a tandem oxidation-condensation or condensation reaction
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An easy and efficient propylphosphonic anhydride (T3P)-DMSO or T3P mediated oxidation-condensation or condensation reaction for the synthesis of quinoxalines derived from the interaction of different arrays of condensing partners with ortho-phenylene diamines (o-PDs) under simple and mild reaction conditions in one step has been reported for the first time.
- Harsha, Kachigere B.,Rangappa, Kanchugarkoppal S.
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p. 57154 - 57162
(2016/07/07)
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- Graphene oxide (GO) or reduced graphene oxide (rGO): Efficient catalysts for one-pot metal-free synthesis of quinoxalines from 2-nitroaniline
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A straightforward one-pot preparation of library of quinoxalines from 2-nitroanilines under entirely metal-free conditions is described. Initial reduction of nitroaniline with hydrazine hydrate is efficiently catalyzed by graphene oxide (GO) or reduced graphene oxide (rGO), and further one-pot tandem reactions with 1,2-dicarbonyl compounds or with α-hydroxy ketones afford quinoxalines in excellent yields. The catalyst is recovered, characterized, and found to be recyclable for consecutive four runs examined with appreciable conversions.
- Roy, Babli,Ghosh, Sujit,Ghosh, Pranab,Basu, Basudeb
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p. 6762 - 6767
(2016/01/30)
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- A highly cis-selective and enantioselective metal-free hydrogenation of 2,3-disubstituted quinoxalines
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A wide range of 2,3-disubstituted quinoxalines have been successfully hydrogenated with H2 using borane catalysts to produce the desired tetrahydroquinoxalines in 80-99% yields with excellent cis selectivity. Significantly, the asymmetric reaction employing chiral borane catalysts generated by the in situ hydroboration of chiral dienes with HB(C6F5)2 under mild reaction conditions has also been achieved with up to 96% ee, and represents the first catalytic asymmetric system to furnish optically active cis-2,3-disubstituted 1,2,3,4-tetrahydroquinoxalines.
- Zhang, Zhenhua,Du, Haifeng
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supporting information
p. 623 - 626
(2015/03/04)
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- Chemoselective synthesis of quinoxalines and benzimidazoles by silica gel catalysis
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Treatment of nitroolefins and o-phenylenediamine with silica gel catalyst produced quinoxalines mainly in THF, but gave benzimidazoles efficiently in water. Such a solvent-dependent chemoselective reaction has prominent features of affording two cyclized products selectively with the same substrate, short reaction time, operational simplicity, as well as available starting materials and nontoxic catalysts. In addition, the scope and limitations were explored and a plausible reaction mechanism is proposed.
- Li, Chunmei,Zhang, Furen,Yang, Zhen,Qi, Chenze
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supporting information
p. 5430 - 5433
(2014/12/11)
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- α-nitro epoxides in organic synthesis: Development of a one-pot organocatalytic strategy for the synthesis of quinoxalines
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A new strategy for the synthesis of biologically active quinoxalines by using versatile α-nitro epoxides as starting compounds has been developed. In addition, the in situ organocatalytic epoxidation of electron-poor nitro olefins followed by condensation with 1,2-phenylenediamines to provide quinoxalines in one pot has been demonstrated. The reaction of easily accessible nitro olefins with the tBuOOH/1,8-diazabicycloundec-7-ene (TBHP/DBU) organocatalytic system gives rise to the corresponding α-nitro epoxides, which are suitable for subsequent reaction with 1,2-phenylenediamines under mild conditions to give quinoxaline heterocycles in up to 82 % yield. Copyright
- Ibrahim, Mohammad M.,Grau, Dominik,Hampel, Frank,Tsogoeva, Svetlana B.
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p. 1401 - 1405
(2014/03/21)
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- α-Nitro Epoxides in Organic Synthesis: Development of a One-Pot Organocatalytic Strategy for the Synthesis of Quinoxalines
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A new strategy for the synthesis of biologically active quinoxalines by using versatile α-nitro epoxides as starting compounds has been developed. In addition, the in situ organocatalytic epoxidation of electron-poor nitro olefins followed by condensation with 1,2-phenylenediamines to provide quinoxalines in one pot has been demonstrated.
- Ibrahim, Mohammad M.,Grau, Dominik,Hampel, Frank,Tsogoeva, Svetlana B.
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p. 1401 - 1405
(2015/10/05)
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- Nitroepoxides as versatile precursors to 1,4-diamino heterocycles
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Nitroepoxides are easily transformed into 1,4-diamino heterocycles such as quinoxalines and pyrazines by treatment with 1,2-benzenediamines and ammonia, respectively. Additionally, related saturated heterocycles, such as piperazines and tetrahydroquinoxalines, can be accessed by treatment with 1,2-diamines and a reducing agent. These transformations are efficient, provide access privileged, bioactive structures, and produce minimal waste.
- Vidal-Albalat, Andreu,Rodriguez, Santiago,Gonzalez, Florenci V.
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p. 1752 - 1755
(2014/04/17)
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- AgNO2-mediated direct nitration of the quinoxaline tertiary benzylic C-H bond and direct conversion of 2-methyl quinoxalines into related nitriles
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A unique method for AgNO2-mediated direct nitration of the quinoxaline tertiary C-H bond and direct conversion of 2-methyl quinoxalines into 2-quinoxaline nitriles under oxidative conditions has been developed. This protocol provides an efficient way to access quinoxaline containing nitroalkanes and nitriles depending on different substrate selection. the Partner Organisations 2014.
- Wu, Degui,Zhang, Jian,Cui, Jianhai,Zhang, Wei,Liu, Yunkui
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supporting information
p. 10857 - 10860
(2014/09/30)
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- An iodobenzene-catalysed domino route toward quinoxaline derivatives from simple ketones and o-phenylenediamines in one pot
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An iodobenzene-catalysed domino route to quinoxalines from ketones and o-phenylenediamines in one pot has been developed. This transformation consisted of the generation of Koser's generation, α-tosyloxylation of ketones, nucleophilic substitution and intramolecular dehydration with o-phenylenediamines, and dehydrogenation. Website
- Li, Xiaoqing,Zhou, Can,Hu, Zhiyan,Xu, Xiangsheng
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p. 579 - 581
(2013/10/22)
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- Acceptorless dehydrogenation of nitrogen heterocycles with a versatile iridium catalyst
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Gas up: A cyclometalated iridium complex is found to catalyze the dehydrogenation of various benzofused N-heterocycles, thus releasing H 2. Driven by as low as 0.1 mol % catalyst, the reaction affords quinolines, indoles, quinoxalines, isoquinolines, and β-carbolines in high yields. Copyright
- Wu, Jianjun,Talwar, Dinesh,Johnston, Steven,Yan, Ming,Xiao, Jianliang
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supporting information
p. 6983 - 6987
(2013/07/26)
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- Cu(II)-catalyzed synthesis of quinoxalines from o-phenylenediamines and nitroolefins
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An easy and efficient copper-catalyzed reaction for the synthesis of quinoxalines from o-phenylenediamines and nitroolefins is developed. This reaction could proceed well without additional base and be applied to various available substrates with a one-step synthetic procedure in moderate to good yields.
- Chen, Yongxin,Li, Kangning,Zhao, Mingming,Li, Yuanjiao,Chen, Baohua
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supporting information
p. 1627 - 1630
(2013/03/28)
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- A new facile, efficient synthesis and structure peculiarity of quinoxaline derivatives with two benzimidazole fragments
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A highly efficient and versatile method for the synthesis of quinoxaline derivatives with two benzimidazole fragments have been developed on the basis of the ring contraction of 3-(benzimidazo-2-yl)quinoxalin-2(1H)-one with 1,2-diaminobenzene and its various types of substituted and condensed derivatives. Owing to the inter- and intramolecular processes, involving self association, proton exchange, conformational, and/or tautomeric exchanges between several forms for most of the bis-benzimidazolylquinoxalines signals of bridged and neighboring carbon atoms and the hydrogen atoms of the neighboring carbon atoms of benzimidazole fragments in the NMR spectra are broadened. The conjugation between the benzimidazole fragments and the quinoxaline core of the molecules is increased from the quinoxaline derivative (10c) to its thiadiazol[f]- (17) and pyrrolo[a]-(19) annulated derivatives, resulting in a greater planarity of the molecule as a whole.
- Mamedov, Vakhid A.,Zhukova, Nataliya A.,Syakaev, Victor V.,Gubaidullin, Aidar T.,Beschastnova, Tat'Yana N.,Adgamova, Dil'Bar I.,Samigullina, Aida I.,Latypov, Shamil K.
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supporting information
p. 1403 - 1416
(2013/02/23)
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- Surfactant micelles as microreactors for the synthesis of quinoxalines in water: Scope and limitations of surfactant catalysis
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The scope and limitations of surfactants as catalysts for the synthesis of quinoxalines using microreactors made of the surfactants in water has been assessed. The catalytic potential followed the order: non-ionic surfactants > anionic surfactants > Bronsted acid surfactants > cationic surfactants. The non-ionic surfactant, Tween 40, is the most effective catalyst affording excellent yields within a short reaction time at room temperature and is compatible with different variations of the 1,2-diketones and 1,2-diamines. The reaction medium (spent water) containing the catalyst, as well as the catalyst itself (recovered Tween 40) can be reused for five consecutive reactions. The better catalytic efficiency of the surfactant (Tween 40) compared to the various Lewis/Bronsted acids, as well as the surfactant combined Lewis acid, suggests that surfactants, which generate microreactor assemblies at the interface, are better suited as catalytic aids to promote organic reactions in water. The inferior results obtained in organic solvents, which provide a homogeneous reaction mixture compared to those obtained in water, indicate the specific role of water. This has been depicted as a synergistic dual activation through the hydrogen bond mediated formation of supramolecular assemblies involving a water dimer and the reactants. The catalytic assistance of the surfactant could be ascribed to the ability of the surfactant molecule to undergo hydrophobic and hydrogen bond forming interactions with water and the reactants in orienting the reactants at the water interface and encapsulating inside the microreactors to facilitate the cyclocondensation. The Royal Society of Chemistry 2013.
- Kumar, Dinesh,Seth, Kapileswar,Kommi, Damodara N.,Bhagat, Srikant,Chakraborti, Asit K.
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p. 15157 - 15168
(2013/09/02)
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- A green synthesis of quinoxalines and 2,3-dihydropyrazines
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Quinoxaline and dihydropyrazine derivatives were obtained in high yields by simple addition of 1,2-diamines and 1,2-dicarbonyl compounds in water. In some cases, the products spontaneously precipitated from the reaction mixture, making it possible to recover and reuse the mother liquor for further condensations. The very mild reaction conditions, the high yields of the products, and the absence of any catalyst make this methodology an efficient and green route to quinoxalines and dihydropyrazines. Georg Thieme Verlag Stuttgart New York.
- Delpivo, Camilla,Micheletti, Gabriele,Boga, Carla
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p. 1546 - 1552
(2013/06/27)
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- Near room temperature cross-coupling reactions of arene boronic acids with a quinoxaline 1,4-dioxide benzylsulfanyl derivative
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A new quinoxaline 1,4-dioxide benzylsulfanyl derivative was tested under mild conditions in copper-mediated Liebeskind-Srogl (LS) cross-coupling reactions with arene boronic acids. These first organometallic cross-coupling reactions performed on a quinoxaline 1,4-dioxide derivative open new perspectives in medicinal chemistry. They represent also the first LS cross-couplings run with an electrophile equipped with an aryl N-oxide moiety. A mild an efficient protocol was developed to prepare quinoxaline 1,4-dioxide derivatives. A benzylsulfanyl quinoxaline 1,4-dioxide derivative was engaged as an electrophilic partner in copper-mediated Liebeskind-Srogl cross-coupling reactions with a wide range of arene boronic acids. These experiments represent the first organometallic coupling reactions on quinoxaline 1,4-dioxide derivatives. Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.
- Dahbi, Samir,Bisseret, Philippe
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supporting information; experimental part
p. 3759 - 3763
(2012/09/25)
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- Logic design and synthesis of quinoxalines via the integration of iodination/oxidation/cyclization sequences from ketones and 1,2-diamines
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A novel protocol for the synthesis of quinoxalines has been developed from simple ketones and 1,2-diamines. This process underwent a logic approach to bis-substituted quinoxalines via a consecutive iodination/Kornblum oxidation/cyclization in the presence of I2/CuO/DMSO and to mono-substituted quinoxalines via an iodination/cyclization/aromatization in the presence of I2/CuO/K3PO4·3H 2O.
- Lian, Mi,Li, Qi,Zhu, Yanping,Yin, Guodong,Wu, Anxin
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p. 9598 - 9605
(2012/11/07)
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- La(OTf)3 catalyzed synthesis of quinoxalines
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Lanthanum trifluoromethanesulfonate is found to be an efficient and highly effective catalyst for the synthesis of quinoxalines 3a-l by the condensation of aromatic 1,2-diamines 1 with 1,2-diketones 2 under ambient conditions. The method is simple and eff
- Raju, B. China,Ramachandra
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experimental part
p. 756 - 759
(2012/06/30)
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- Pyrrolo[1,2-a]quinoxalines: Novel synthesis via annulation of 2-alkylquinoxalines
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In an attempt to synthesize a novel homoleptic complex 3 from 2-methyl-3-phenylquinoxaline 1 and Ir(acac)3 for application as a triplet emitter in OLEDs (organic light-emitting diodes) no cyclometalation was observed. Instead, an annulation to 1-methyl-4-phenylpyrrolo[1,2-a]quinoxaline 2 was observed. Since pyrroloquinoxalines are potentially bioactive and few paths for their synthesis are known, selected reactions and conditions were investigated, suggesting Ir(acac)3 as catalyst and proving glycerol to be a reactant.
- Ammermann, Sven,Hrib, Christian,Jones, Peter G.,Du Mont, Wolf-Walther,Kowalsky, Wolfgang,Johannes, Hans-Hermann
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supporting information
p. 5090 - 5093
(2013/01/15)
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- Gold-catalyzed oxidation of arylallenes: Synthesis of quinoxalines and benzimidazoles
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A gold-catalyzed oxidation of arylallenes to form α-diketones and aldehydes in good yields is presented. Further directed synthesis of quinoxalines and benzimidazoles, via the condensation of the resulting α-diketones and aldehydes with benzene-1,2-diamine, was achieved in high yields.
- Cui, Dong-Mei,Zhuang, Dan-Wen,Chen, Ying,Zhang, Chen
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experimental part
p. 860 - 865
(2011/08/05)
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- CeCl3·7H2O-catalyzed synthesis of quinoxaline derivatives in liquid PEG-400
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A mild and efficient route for the synthesis of quinoxaline derivatives utilizing cerium chloride heptahydrate (CeCl3·7H2O) as a novel catalyst in poly(ethylene glycol) (PEG-400) under mild conditions was described.
- Wu, Fang-Wen,Hou, Rei-Sheu,Wang, Huey-Min,Kang, Iou-Jiun,Chen, Ling-Ching
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experimental part
p. 2313 - 2320
(2011/11/06)
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- Niobium pentachloride as a highly efficient catalyst for the synthesis of quinoxaline derivatives
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Niobium pentachloride is found to be an efficient catalyst for the synthesis of quinoxaline derivatives via the condensation of aromatic 1,2-dicarbonyl compounds (or unsymmetrical 1,2-diketones or α-hydroxy ketones) with 1,2-diamines. All the reactions were performed at room temperature while using acetonitrile as solvent. The present methodology offers several advantages such as excellent yields, short reaction time and environmentally benign milder reaction conditions.
- Kidwai, Mazaahir,Mishra, Neeraj Kumar,Bhatnagar, Divya,Jahan, Anwar
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experimental part
p. 5051 - 5054
(2012/07/03)
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- Elemental iodine or diphenyl diselenide in the [bis(trifluoroacetoxy)iodo] benzene-mediated conversion of alkynes into 1,2-diketones
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Both elemental iodine and diphenyl diselenides, in the presence of [bis(trifluoroacetoxy)iodo]benzene (PIFA), promote the transformation of internal alkynes into the corresponding 1,2-diketones. The reactions carried out in the presence of iodine unfortunately did not proceed with complete conversion of the starting alkynes. On the other hand, diphenyl diselenide was more efficient and gave satisfactory transformation of the starting alkynes into 1,2-diketones in better yields. The structure of the vicinal dicarbonyl compounds were confirmed by applying a subsequent condensation reaction to construct the corresponding quinoxaline derivatives. Both elemental iodine and diphenyl diselenide in the presence of [bis(trifluoroacetoxy)iodo]benzene (PIFA) promote the transformation of internal alkynes into 1,2-diketones. The structure of the products were confirmed by transformation into the corresponding quinoxaline derivatives, two of which were studied by X-ray analysis. Copyright
- Tingoli, Marco,Mazzella, Mauro,Panunzi, Barbara,Tuzi, Angela
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experimental part
p. 399 - 404
(2011/02/28)
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- Synthesis of quinoxalines catalysed by cetyltrimethyl ammonium bromide (CTAB) in aqueous media
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A facile and simple method has been developed for the condensation of 1,2-diaminobenzenes with α-bromoketones to form quinoxalines with good yields using cetyltrimethyl ammonium bromide (CTAB) in aqueous media. The efficiency of this reaction was demonstrated by the compatibility with nitro, methyl, methoxy, fluoro chloro bromo and furanyl groups. The important features of the methodology are broad substrate scope, simple workup, and no requirement for metal catalysts.
- Huang, Tieqiang,Zhang, Qaing,Chen, Jiuxi,Gao, Wenxia,Ding, Jinchang,Wu, Huayue
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experimental part
p. 761 - 765
(2010/03/24)
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- A recyclable copper catalysis in quinoxaline synthesis from α-hydroxyketones and o-phenylenediamines
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o-Phenylenediamines react with α-hydroxyketones in toluene at 100 °C in the presence of a catalytic amount of a copper catalyst along with MS 4A under O2 atmosphere to afford the corresponding quinoxalines in high yields. The catalytic system c
- Cho, Chan Sik,Ren, Wen Xiu
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experimental part
p. 3215 - 3217
(2010/01/06)
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- PHENAZINE AND QUINOXALINE SUBSTITUTED AMINO ACIDS AND POLYPEPTIDES
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Disclosed herein are non-natural amino acids and polypeptides that include at least one non-natural amino acid, and methods for making such non-natural amino acids and polypeptides. The non-natural amino acids, by themselves or as a part of a polypeptide, can include a phenazine or quinoxaline substituent. Also disclosed herein are non-natural amino acid polypeptides that are further modified post-translationally, methods for effecting such modifications, and methods for purifying such polypeptides.
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Page/Page column 173
(2008/12/07)
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- ORGANOMETALLIC COMPLEX, AND LIGHT-EMITTING ELEMENT AND LIGHT-EMITTING DEVICE USING THE ORGANOMETALLIC COMPLEX
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A material which can emit phosphorescence is disclosed. Further, a light-emitting element having good chromaticity is disclosed. An embodiment of the present invention is an organometallic complex including a structure as represented by the general formul
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Page/Page column 55-56
(2010/11/08)
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