- In water organic synthesis: Introducing itaconic acid as a recyclable acidic promoter for efficient and scalable synthesis of quinoxaline derivatives at room temperature
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Substituted quinoxaline derivatives are traditionally synthesized by co-condensation of various starting materials. Herein, we describe a novel environmentally benign in water synthetic route for the synthesis of structurally and electronically diverse ninety quinoxalines with readily available substituted o-phenylenediamine and 1,2-diketones using cheap and biodegradable itaconic acid as a mild acid promotor in 1 hours. The reaction is performed at room temperature, which proceeds through cyclo-condensation reaction followed by obtaining the aforesaid nitrogen-containing heterocyclic adducts without performing the column chromatography up to 96% total yields. The simplicity, high efficiency, and reusable of the catalyst merits this reaction condition as “green synthesis” which enables it to be useful in synthetic transformations upto gram scale level.
- Tamuli, Kashyap J.,Nath, Shyamalendu,Bordoloi, Manobjyoti
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supporting information
p. 983 - 1002
(2021/02/27)
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- Iron-catalyzed one-pot synthesis of quinoxalines: Transfer hydrogenative condensation of 2-nitroanilines with vicinal diols
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Here, we report iron-catalyzed one-pot synthesis of quinoxalines via transfer hydrogenative condensation of 2-nitroanilines with vicinal diols. The tricarbonyl (η4-cyclopentadienone) iron complex, which is well known as the Kn?lker complex, catalyzed the oxidation of alcohols and the reduction of nitroarenes, and the corresponding carbonyl and 1,2-diaminobenzene intermediates were generated in situ. Trimethylamine N-oxide was used to activate the iron complex. Various unsymmetrical and symmetrical vicinal diols were applied for transfer hydrogenation, resulting in quinoxaline derivatives in 49-98% yields. A plausible mechanism was proposed based on a series of control experiments. The major advantages of this protocol are that no external redox reagents or additional base is needed and that water is liberated as the sole byproduct. This journal is
- Chun, Simin,Hong, Junhwa,Hong, Suckchang,Lee, Seok Beom,Oh, Dong-Chan,Putta, Ramachandra Reddy
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p. 18225 - 18230
(2021/06/03)
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- NaOH-Mediated Direct Synthesis of Quinoxalines from o-Nitroanilines and Alcohols via a Hydrogen-Transfer Strategy
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A NaOH-mediated sustainable synthesis of functionalized quinoxalines is disclosed via redox condensation of o-nitroamines with diols and α-hydroxy ketones. Under optimized conditions, various o-nitroamines and alcohols are well tolerated to generate the desired products in 44-99% yields without transition metals and external redox additives.
- Wang, Yan-Bing,Shi, Linlin,Zhang, Xiaojie,Fu, Lian-Rong,Hu, Weinan,Zhang, Wenjing,Zhu, Xinju,Hao, Xin-Qi,Song, Mao-Ping
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p. 947 - 958
(2021/01/14)
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- Application of a reusable Co-based nanocatalyst in alcohol dehydrogenative coupling strategy: Synthesis of quinoxaline and imine scaffolds
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A nitrogen doped carbon supported cobalt catalyzed efficient synthesis of imines and quinoxaline motifs is reported. Co(OAc)2-Phen/Carbon-800 (Co-phen/C-800) showed the superior reactivity compared to other materials prepared at different temperature, in the synthesis of quinoxalines by the coupling between diamines and diols. Moreover, applying the transfer hydrogenation and acceptorless dehydrogenative coupling strategy, imines and quinoxaline derivatives were synthesized from the nitro compounds. The practical applicability of this protocol was demonstrated by the gram-scale synthesis and the reusability of the catalyst upto 8th cycle. Furthermore, several kinetic experiments were carried out to realize the probable mechanism.
- Panja, Dibyajyoti,Paul, Bhaskar,Balasubramaniam, Bhuvaneshwari,Gupta, Raju K.,Kundu, Sabuj
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- Nickel-Catalyzed Direct Synthesis of Quinoxalines from 2-Nitroanilines and Vicinal Diols: Identifying Nature of the Active Catalyst
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The inexpensive and simple NiBr2/1,10-phenanthroline system-catalyzed synthesis of a series of quinoxalines from both 2-nitroanilines and 1,2-diamines is demonstrated. The reusability test for this system was performed up to the seventh cycle, which afforded good yields of the desired product without losing its reactivity significantly. Notably, during the catalytic reaction, the formation of the heterogeneous Ni-particle was observed, which was characterized by PXRD, XPS, and TEM techniques.
- Shee, Sujan,Panja, Dibyajyoti,Kundu, Sabuj
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p. 2775 - 2784
(2020/03/13)
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- Cooperative iridium complex-catalyzed synthesis of quinoxalines, benzimidazoles and quinazolines in water
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Herein, an efficient methodology for the synthesis of a diverse class of N-heterocyclic moieties, such as quinoxalines, benzimidazoles and quinazolines, was developed in water using bio-renewable alcohols. The quinoxalines were successfully synthesized from a wide range of diamines and nitroamines with diols in air. Interestingly, benzimidazoles and quinazolines were synthesized with excellent isolated yields without using any external base. Finally, the preparative scale synthesis of various N-heterocycles and pharmaceutically active quinoxalines established the practicability of this protocol. For this iridium system, a metal-ligand cooperative mechanism was proposed based on kinetic and DFT studies.
- Chakrabarti, Kaushik,Maji, Milan,Kundu, Sabuj
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supporting information
p. 1999 - 2004
(2019/04/27)
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- Cobalt complex catalyzed atom-economical synthesis of quinoxaline, quinoline and 2-alkylaminoquinoline derivatives
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A new phosphine-free Co(ii) complex-catalyzed synthesis of various quinoxalines via dehydrogenative coupling of vicinal diols with both o-phenylenediamines and 2-nitroanilines is reported. This complex was also effective for the synthesis of quinolines. The practical aspect of this catalytic system was revealed by the one-pot synthesis of 2-alkylaminoquinolines.
- Shee, Sujan,Ganguli, Kasturi,Jana, Kalipada,Kundu, Sabuj
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supporting information
p. 6883 - 6886
(2018/06/26)
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- Rapid, efficient and eco-friendly procedure for the synthesis of quinoxalines under solvent-free conditions using sulfated polyborate as a recyclable catalyst
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An efficient and inexpensive sulfated polyborate catalyst was applied for the rapid synthesis of quinoxaline derivatives from various substituted o-phenylenediamines and 1,2-diketones/α-hydroxy ketones using sulfated polyborate is described. The catalyst has the advantage of Lewis as well as Bronsted acidity and recyclability without significant loss in catalytic activity. The key advantages of the present method are high yields, short reaction times, solvent-free condition, easy workup, and ability to tolerate a variety of functional groups, which give economical as well as ecological rewards. [Figure not available: see fulltext.]
- Indalkar, Krishna S,Khatri, Chetan K,Chaturbhuj, Ganesh U
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p. 141 - 148
(2017/02/23)
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- Ionic liquid functionalized cellulose as an efficient heterogeneous catalyst for the facile and green synthesis of benzoxazine, pyrazine and quinoxaline derivatives in aqueous media
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Immobilization of acidic ionic liquid, 1-methyl-3-(3-trimethoxysilylpropyl) imidazolium hydrogen sulfate on cellulose (Cell-[pmim]HSO4) as an efficient heterogenous catalyst for the simple and environmentally benign synthesis of benzoxazine, pyrazine and quinoxaline derivatives in aqueous media at room temperature is described. The catalyst was characterized by FTIR spectroscopy and X-ray diffraction pattern. This method provides several advantages such as mild reaction conditions, environmentally friendly catalyst, good to excellent yields and simple work-up procedure.
- Moghaddam, Sevil Vaghefi,Valizadeh, Hassan
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p. 1517 - 1524
(2016/07/06)
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- A zirconium Schiff base complex immobilized on starch-coated maghemite nanoparticles catalyzes heterogeneous condensation of 1,2-diamines with 1,2-dicarbonyl compounds
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A magnetically separable zirconium Schiff base nanocatalyst was synthesized under ultrasonic agitation. TEM images revealed a uniform spherical particle shape with average size of 10-14 nm for the as-prepared catalyst. The catalytic performance of ZrOL2@SMNP in the heterogeneous condensation of various 1,2-diamines and 1,2-dicarbonyls for the synthesis of heterocyclic compounds in ethanol has been explored.
- Jafarpour, Maasoumeh,Rezaeifard, Abdolreza
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p. 205 - 211
(2016/02/20)
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- Efficient solvent-free synthesis of pyridopyrazine and quinoxaline derivatives using copper-DiAmSar complex anchored on SBA-15 as a reusable catalyst
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A catalytic system comprising mesoporous silica functionalized with Cu(II)-DiAmSar was synthesized. This was demonstrated as an efficient heterogeneous catalyst for the synthesis of biologically useful pyridopyrazine and quinoxaline heterocycles under solvent-free conditions. X-ray diffraction, transmission electron microscopy, N2 adsorption-desorption, Fourtier transformation infrared spectroscopy, and thermogravimetric analysis were used to characterize the catalyst and investigate the texture of SBA-15 during the grafting process.
- Mohammadi, Marzieh,Bardajee, Ghasem Rezanejade,Pesyan, Nader Noroozi
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p. 1379 - 1386
(2015/09/01)
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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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p. 1471 - 1478
(2015/09/01)
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- Nano SbCl5.SiO2: An efficient catalyst for the synthesis of quinoxaline derivatives at room temperature under solventless condition
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Nano SbCl5.SiO2 as an eco-friendly and efficient nanocatalyst was applied for quinoxaline derivatives preparation with improved yield. In this protocol, α-diketones and 1,2-diamines were condensed in the presence of nanocatalyst at room temperature under solventless conditions. The method gave good yields of quinoxaline derivatives in short reaction times in comparison with earlier methods. Using nontoxic and inexpensive materials, simple work-up, short reaction times and high yields of the products are the advantages of this method.
- Bamoniri, Abdolhamid,Mirjalili, Bibi Fatemeh,Karbasizadeh, Hassan
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p. 2851 - 2856
(2015/06/02)
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- One-pot synthesis of quinoxalines from reductive coupling of 2-nitroanilines and 1,2-diketones using indium
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The one-pot reduction-cyclization of 2-nitroanilines and 1,2-diketones to give quinoxalines was investigated. Using indium and an appropriate acid such as acetic acid or indium(III) chloride, various quinoxaline derivatives including 2,3-dialkylquinoxalines, 2,3-diphenylquinoxalines, 2,3-di-2-thiophenylquinoxalines, 2,3-di(pyridin-2-yl)quinoxalines, and dibenzo[a,c]phenazines were synthesized in moderate to excellent yield.
- Go, Ahra,Lee, Geunsoo,Kim, Jaeho,Bae, Seolhee,Lee, Byung Min,Kim, Byeong Hyo
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p. 1215 - 1226
(2015/03/04)
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- Zirconium schiff-base complex modified mesoporous silica as an efficient catalyst for the synthesis of nitrogen containing pyrazine based heterocycles
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Zirconium Schiff-base complex modified SBA-15 was synthesized and characterized by powder X-ray diffraction (XRD), BET nitrogen adsorption-desorption methods, IR spectroscopy and thermogravimetric analysis. The XRD and BET analyses show that textural properties of SBA-15 were retained during the grafting procedure. The modified SBA was successfully applied as a heterogeneous catalyst for the synthesis of a library of nitrogen containing pyrazine based heterocycles in good to excellent yields in water media.
- Malakooti, Reihaneh,Bardajee, Ghasem Rezanejade,Mahmoudi, Hesamaldin,Kakavand, Nahale
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p. 853 - 861
(2013/08/23)
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- Poly(N,N ′-dibromo-N-ethyl-benzene-1,3-disulphonamide) and N,N,N ′,N ′-tetrabromobenzene-1,3- disulphonamide as novel catalysts for synthesis of quinoxaline derivatives
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Poly(N,N ′ -dibromo-N-ethyl-benzene-1,3-disulphonamide) [PBBS] and N,N,N ′,N ′ -tetrabromobenzene-1,3- disulphonamide [TBBDA] were used as efficient catalysts for the synthesis of quinoxaline derivatives in excellent yields from 1,2-diamines and 1,2-dicarbonyls under aqueous and solvent-free conditions. [Figure not available: see fulltext.]
- Ghorbani-Vaghei, Ramin,Hajinazari, Somaye
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p. 353 - 358
(2013/07/26)
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- A reusable zirconium(IV) Schiff base complex catalyzes highly efficient synthesis of quinoxalines under mild conditions
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A zirconium(IV) complex of a bidentate Schiff base (ZrL2Cl 2) has been synthesized by the reaction of (z)-N-benzylidene-2- hydroxypropane-1-amine (HL) and ZrCl4. Spectroscopic data and elemental analyses are consistent with a monomeric complex with a ligand:Zr ratio of 2:1. The catalytic activity of ZrL2Cl2 has been investigated for the efficient synthesis of a wide variety of quinoxaline derivatives under mild conditions. The employment of ethanol as an environmentally benign solvent in this high yield method, along with high turnover numbers and reusability of the catalyst providing ready scalability, makes it appropriate for practical applications.
- Jafarpour, Maasoumeh,Rezaeifard, Abdolreza,Haddad, Reza,Gazkar, Somayeh
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- Microwave-assisted synthesis of quinoxaline derivatives using glycerol as a green solvent
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A rapid, efficient, and reliable catalyst-free procedure for the synthesis of quinoxaline derivatives in glycerol under focused microwave irradiation was developed. The reaction proceeded in glycerol without any catalyst making this methodology valuable from both economic and environmental viewpoints.
- Zhou,Zhang,Sun,Wang,Wang,Bai
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p. 1244 - 1247
(2014/03/21)
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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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- Polystyrene-supported AlCl3 as a highly active and reusable heterogeneous lewis acid catalyst for the one-pot synthesis of quinoxalines
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A new and environmentally benign protocol for the synthesis of quinoxaline derivatives through the condensation reactions of 1,2-diketones and 1,2-phenylenediamines using cross-linked polystyrene-supported aluminum chloride (PS/AlCl3) as a highly active and reusable heterogeneous Lewis acid catalyst is described. This polymeric catalyst is stable and can be easily recovered and reused without appreciable change in its efficiency. Copyright
- Rahmatpour, Ali
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p. 472 - 477
(2012/10/29)
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- Glycerin and CeCl3 7H2O: A new and efficient recyclable reaction medium for the synthesis of quinoxalines
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An efficient and environmentally benign process for the synthesis of quinoxalines has been developed using glycerine-cerium chloride as a reaction medium. This method is applicable to a variety of diketones and 1,2-phenylenediamines to afford the corresponding quinoxaline derivatives in excellent yields. The reaction medium was recovered and reused for further reactions without any problem. Taylor & Francis Group, LLC.
- Venkat Narsaiah,Kranthi Kumar
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experimental part
p. 883 - 892
(2012/03/11)
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- Sustainable approach to tandem catalysis: Expedient access to quinoxalines and pyrido[2,3-b]pyrazines from α-hydroxyketones via microwave-induced [(NH4)6Mo7O24·4H 2O - PEG 300] polar paste catalyst system
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[(NH4)6Mo7O24·4H 2O-PEG 300] is introduced as a polar paste catalyst system for tandem synthesis of quinoxalines and pyrido[2,3-b]pyrazines under open-vessel focused microwave irradiation. Low conversions were obtained when catalyst or PEG was used individually. Accordingly, a convenient combination of catalyst and PEG mostly led to quantitative yield of products within 15 min microwave irradiation with good turnover frequency values (11-20 h-1) taking a tandem process into consideration. The salient features of this environmentally benign method are fast conversions, high product selectivity and the use of a low-cost, readily available, nontoxic, catalyst and medium.
- Aghapoor, Kioumars,Mohsenzadeh, Farshid,Mohebi Morad, Mina,Darabi, Hossein Reza
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p. 764 - 767
(2012/10/29)
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- FeCl3 and morpholine as efficient cocatalysts for the one-step synthesis of quinoxalines from α-hydroxyketones and 1,2-diamines
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One-step conversion including intramolecular hydrogen bond decomposition, aerobic oxidation, and condensation from α-hydroxyketones and 1,2-diamines into quinoxalines is reported using FeCl3 and morpholine as cocatalysts. Taylor & Francis Group, LLC.
- Liu, Peng,Lei, Min,You, Hanyun,Chen, Xubing,Chen, Hu,Ma, Lei,Hu, Lihong
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experimental part
p. 236 - 245
(2011/11/06)
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- Heterogeneous SnCl2/SiO2 versus homogeneous SnCl 2 acid catalysis in the benzo[N,N]-heterocyclic condensation
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The scope of homogeneous Lewis acid-catalyzed benzo[N,N]-heterocyclic condensation was expanded to include the use of various metal salts not reported in the literature and SnCl2·2H2O was finally selected. Among various solid supports activated with SnCl2, heterogeneous SnCl2/SiO2 proved to be the most effective and significantly higher conversions were achieved compared to SnCl 2·2H2O itself. The results of TG-DTA and BET indicated that dispersed SnCl2 coordinates with surface hydroxyl groups of silica leading to formation of stable Lewis acid sites. Low catalyst loading, operational simplicity, practicability and applicability to various substrates render this eco-friendly approach as an interesting alternative to previously applied procedures.
- Darabi, Hossein Reza,Aghapoor, Kioumars,Mohsenzadeh, Farshid,Jalali, Mohammad Reza,Talebian, Shiva,Ebadi-Nia, Leila,Khatamifar, Ehsan,Aghaee, Ali
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experimental part
p. 213 - 218
(2011/11/06)
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- Microwave-assisted synthesis of quinoxalines in peg-400
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A rapid and efficient procedure for the synthesis of quinoxaline derivatives has been achieved by condensation of aryl-1,2-diamines with 1,2-dicarbonyl compounds catalyzed by polyethylene glycol under CEM-focused microwave-irradiation conditions. Copyright
- Zhang, Xia-Zhong,Wang, Jin-Xian,Bai, Lin
-
experimental part
p. 2053 - 2063
(2011/07/07)
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- Asymmetric hydrogenation of 2-and 2,3-substituted ouinoxalines with chiral cationic ruthenium diamine catalysts
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The enantioselective hydrogenation of 2-alkyl- and 2-aryl-subsituted quinoxalines and 2,3-disubstituted quinoxalines was developed by using the cationic Ru(η6-cymene)(monosulfonylated diamine)(BArF) system in high yields with up to 99% ee. The counteranion was found to be critically important for the high enantioselectivity and/or diastereoselectivity.
- Qin, Jie,Chen, Fei,Ding, Ziyuan,He, Yan-Mei,Xu, Lijin,Fan, Qing-Hua
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supporting information; experimental part
p. 6568 - 6571
(2012/02/13)
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- A new catalytic method for eco-friendly synthesis of quinoxalines by zirconium (IV) oxide chloride octahydrate under mild conditions
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An environmentally benign catalytic method for efficient synthesis of quinoxaline derivatives via the condensation reaction of 1,2-diamines and 1,2-dicarbonyl compounds using ZrOCl2.8H2O in EtOH as a standard green solvent under mild conditions has been developed. The reusability of the catalyst has been successfully examined without any noticeable loss of its catalytic activity.
- Jafarpour, Maasoumeh,Rezaeifard, Abdolreza,Heidari, Mahdieh
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experimental part
p. 202 - 209
(2012/04/04)
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- Easy access to quinoxaline derivatives using alumina as an effective and reusable catalyst under solvent-free conditions
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Alumina as a cheap, heterogeneous and reusable catalyst can provide environmentally friendly alternatives for synthesis of quinoxaline derivatives via condensation of 1,2-diamines and 1,2-dicarbonyl compounds under solvent-free conditions. The products could be separated simply from catalyst by filtration and the catalyst could be recycled and reused for several times without noticeably decreasing in catalytic activity.
- Jafarpour, Maasoumeh,Rezaeifard, Abdolreza,Danehchin, Maryam
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experimental part
p. 48 - 51
(2011/12/16)
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- Vitamin B1 as a metal-ion-free natural catalyst for sustainable quinoxaline ring condensation under sonochemical conditions
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The role of vitamin B1 as a catalyst is investigated for the quinoxaline ring condensation under various mild reaction conditions. The results revealed that the combination of vitamin B1 and ultrasonic irradiation promotes the reaction more efficiently. The salient features of this environmentally benign method are fast conversions, excellent yields for a wide range of substrates, and the use of a low-cost, readily available, nontoxic, and metal-ion-free natural catalyst. The wide range of turnover frequency values (6-400 h-1) shows that the reaction rate is highly dependent on the nature of the functional groups on the aromatic ring of substrates. Moreover, a plausible mechanism for the catalytic action of vitamin B1 has been introduced.
- Aghapoor, Kioumars,Mohsenzadeh, Farshid,Talebian, Shiva,Tehrani, Mohammad Jafar,Balavar, Yadollah,Khanalizadeh, Golriz,Darabi, Hossein Reza
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experimental part
p. 619 - 624
(2012/01/15)
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- Nano-TiO2: An eco-friendly alternative for the synthesis of quinoxalines
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Nano-TiO2 as an eco-friendly and efficient nanocatalyst was applied for quinoxaline preparation with improved yield. In this protocol, diketones and 1,2-diamines were condensed in the presence of catalyst at room temperature.
- Mirjalili, Bi Bi Fatemeh,Akbari, Ali
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experimental part
p. 753 - 756
(2012/01/05)
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- Synthesis of quinoxalines in presence of zinc triflate
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A simple and efficient method for the synthesis of quinoxaline derivatives has been developed. The reactions were carried out in presence of zinc triflate in acetonitrile reflux. The method is applicable to a variety of diketones and 1,2-phenylenediamines to afford the corresponding derivatives in excellent yields.
- Subrahmanyam, C. Siva,Narayanan
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experimental part
p. 1331 - 1333
(2011/12/21)
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- Zirconium(IV) chloride as versatile catalyst for the expeditious synthesis of quinoxalines and pyrido[2,3-b]pyrazines under ambient conditions
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Among the various transition metal chlorides, zirconium(IV) chloride was found to be an efficient catalyst for the rapid synthesis of a wide range of 2,3-dialkyl- and 2,3-diaryl-quinoxaline and pyrido[2,3-b]pyrazine derivatives in excellent yields at room temperature. The remarkable features of this catalytic process are the mild reaction conditions, quantitative yields, short reaction times, high conversions, tolerability of various functional groups, clean reaction profiles, and operational simplicity. Graphical Abstract: Among the various transition metal chlorides, zirconium(IV) chloride was found to be an efficient catalyst for the rapid synthesis of a wide range of 2,3-dialkyl- and 2,3-diaryl-quinoxaline and pyrido[2,3-b]pyrazine derivatives in excellent yields at room temperature. The remarkable features of this catalytic process are the mild reaction conditions, quantitative yields, short reaction times, high conversions, tolerability of various functional groups, clean reaction profiles, and operational simplicity.
- Aghapoor, Kioumars,Darabi, Hossein Reza,Mohsenzadeh, Farshid,Balavar, Yadollah,Daneshyar, Hesam
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experimental part
p. 49 - 53
(2011/12/14)
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- Magnetic Fe3O4 nanoparticles as new, efficient, and reusable catalysts for the synthesis of quinoxalines in water
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A novel, environmentally friendly procedure has been developed for the synthesis of quinoxaline derivatives in the presence of magnetic Fe 3O4 nanoparticles. The reaction between 1,2-diamines and 1,2-dicarbonyl compounds was carried out in water to afford quinoxaline derivatives in high yield. The catalyst can be recovered by the use of an external magnet and reused for five cycles with almost consistent activity. CSIRO 2010.
- Lue, Hong-Yan,Yang, Shu-Hong,Deng, Jia,Zhang, Zhan-Hui
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experimental part
p. 1290 - 1296
(2011/04/15)
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- Synthesis of quinoxaline derivatives catalyzed by PEG-400
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Polyethylene glycol (PEG) was found to be an effective catalyst for the condensation of 1,2-diamines with 1,2-dicarbonyl compounds to afford the corresponding quinoxaline derivatives in excellent yields under mild reaction conditions.
- Zhang, Xia Zhong,Wang, Jin Xian,Sun, Yong Jun,Zhan, Hong Wen
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experimental part
p. 395 - 398
(2010/12/24)
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- Room temperature facile synthesis of quinoxalines catalyzed by amidosulfonic acid
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(Chemical Equation Presented) Amidosulfonic acid NH2-SO 3H catalyzed direct condensations of o-phenylenediamines with α-diketones at room temperature in organic solvents to afford quinoxalines in excellent yields. The amidosulfonic acid as a solid acid catalyst in this preparation was efficient and recoverable.
- Li, Zhenjiang,Li, Weisi,Sun, Yingjie,Huang, He,Ouyang, Pingkai
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p. 285 - 288
(2008/09/19)
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- Efficient route to quinoxalines catalyzed by sulfamic acid in tap water suspension
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Quinoxalines were synthesized via direct condensations of o-phenylenediamines with α-diketones promoted by sulfamic acid at room temperature in tap water suspension in high yields and by simple work-up.
- Li, Zhenjiang,Li, Weisi,Ren, Xinghua,Sun, Yingjie,Shi, Yuhu,Ouyang, Pingkai
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p. 125 - 130
(2008/02/12)
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- Photoinduced Nitro-Nitrite Rearrangement of 5-Nitroquinoxalines
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Unlike known o-nitro methyl derivatives of aromatic compounds, 6-methyl-5-nitro-, 2,3,6-trimethyl-5-nitro-, and 7-methyl-6-nitroquinoxaline and 1,6-dimethyl-5-nitroquinoxalinium perchlorate do not exhibit photochromism in aqueous-ethanolic solutions under conditions of flash photolysis with a time resolution of 50 μs. Under conditions of continuous photolysis, these 5-nitromethylquinoxaline derivatives and also 5-nitroquinoxaline undergo nitro-nitrite rearrangement to give 5-quinoxalinol derivatives with quantum yields ranging from 1 × 10-4 to 3 × 10-3; the efficiency of the photochemical reaction increases when irradiation is performed with a shorter-wave light. 6-Nitro derivatives do not form stable products of photochemical transformations under the same conditions.
- El'tsov,Selitrenikov,Rtishchev
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p. 285 - 294
(2007/10/03)
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- 13C Nuclear Magnetic Resonance Spectra of Quinoxaline Derivatives
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The 13C n.m.r. spectra of a series of 5-, 6-, and 2-substituted quinoxalines have been analysed by consideration of their 1H coupled spectra.Typical values of the coupling constants are: C(2,3), 1JCH 181.9, 2JCH 11.4, C(5,8), 1JCH 162.6, 3JCH 6.5, C(6.7), 1JCH 159.4, 3JCH 9.1; C(9), 3JCH(2) = 3JCH(7) = 10.0, 3JCH(5) 5.4; C(10), 3JCH(3) = 3JCH(6) = 10.0, 3JCH(8) 5.4 Hz.The magnitudes of the coupling constants in the benzenoid ring are similar to these for the corresponding positions in naphthalene, but application of naphthalene chemical shift substitutions effects leads in some cases to the wrong peak sequence in the related quinoxalines.Within the quinoxaline series itself, however, acceptable additivity of substituent effects is found (+/- 0.8 p.p.m.), provided that the reference compounds are carefully chosen.Analysis of mixtures of quinoxalines from substituted o-phenylenediamines and α-oxo-aldehydes is possible by consideration of the multiplicity of the ring-junction quaternary carbon signals in the fully coupled spectra.
- McNab, Hamish
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p. 357 - 364
(2007/10/02)
-