- Star-shaped Keggin-type heteropolytungstate nanostructure as a new catalyst for the preparation of quinoxaline derivatives
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In this work, we report the novel successful preparation of the Keggin-type Cs(CTA)2PW12O40 (CTA = cetyltrimethylammonium cation) nanostructure by a microemulsion method. The microemulsion system included the cationic surfactant CTAB, 1-butanol as co-surfactant, isooctane as oil phase, and an aqueous solution containing CsNO3. The Cs(CTA)2PW12O40 nanostructure was formed by the addition of an aqueous solution of phosphotungstic acid to the microemulsion solution. Characterization of the resultant nanostructure was done using FT-IR spectroscopy, X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray analysis, and CHN elemental analysis. The product was found to be a star-shaped nanostructure composed of some nanorods whose diameter and length are about 100 nm and 500 nm, respectively. The prepared nanostructure was used as a recoverable catalyst for the synthesis of quinoxaline derivatives by the condensation of 1,2-diamines with 1,2-dicarbonyl compounds, which afforded the products in good to high yields in short reaction times.
- Masteri-Farahani, Majid,Ghorbani, Melika,Ezabadi, Ali,Farrokhinia, Niki,Ghaemmaghami, Atekeh-Sadat
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- Zirconium(IV)-modified silica gel: Preparation, characterization and catalytic activity in the synthesis of some biologically important molecules
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Zirconium modified silica gel was prepared by the grafting method and the resulting organic-inorganic hybrid material was found to be a highly effective catalyst for the range of organic transformations such as syntheses of coumarins, quinoxalines and 2,4
- Sharma,Sharma, Chetna
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- Synthesis of a polymer-capped palladium nanoparticles and its application as a reusable catalyst in oxidative coupling reaction of α-hydroxyketones and 1,2-diamines for preparation of pyrazines and quinoxalines
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A novel method for the synthesis of pyrazines and quinoxalines has been developed using α-hydroxyketones and 1,2-diamines in the presence of cross-linked poly(4-vinylpyridine)-stabilized Pd(0) nanoparticles, [P4-VP]-PdNPs. The catalyst was easily prepared and characterized using various techniques such as FT-IR and UV–Vis spectroscopy, AAS, TEM, FESEM, EDX analysis and XRD. The results confirm a good dispersion of palladium nanoparticles on the polymer support. The catalyst displayed good catalytic activity when applied to the synthesis of quinoxalines via condensation of α-hydroxyketones with 1,2-diamines. A few pyrazine derivatives and various quinoxalines are prepared via coupling reaction of α-hydroxyketones and 1,2-diamines in high–excellent yields (81–99%) with short reaction times. The quinoxalines products were characterized by FT-IR, 1H and 13C NMR spectroscopy, and the physical properties were compared to the literature values of known compounds. The advantages of the present method over conventional classical methods are rapid and very simple work-up, and the catalyst is reusable many times without a significant loss in its activity.
- Zarchi, Mohammad Ali Karimi,Abadi, Seyed Shahab Addin Darbandizadeh Mohammad
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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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- Iodine-mediated efficient synthesis of 2,3-dihydro-pyrazines
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The synthesis of 2,3-dihydro-pyrazines has been developed by an efficient protocol of annulations of 1,2-diketones and ethylenediamine. A variety of 2,3-dihydro-pyrazines were prepared in high yields in the presence of a catalytic amount of iodine.
- Dong, Yansheng,Huang, Li,Yi, Fengping
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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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- An Improved Synthesis of Multi-Substituted Pyrazines under Catalyst- and Solvent-Free Conditions
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A one-pot pseudo four-component reaction between a variety of 2-hydroxy-1,2-diarylethanone derivatives and ammonium acetate or amines has been developed to synthesize substituted pyrazines under catalyst-free and solvent-free conditions. This procedure provides a synthetic method to access pyrazine derivatives in excellent yields under green conditions.
- Tamaddon, Fatemeh,Tafti, Arefeh Dehghani,Pooramini, Farzaneh
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- Increasing the triplet lifetime and extending the ground-state absorption of biscyclometalated Ir(III) complexes for reverse saturable absorption and photodynamic therapy applications
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The synthesis, photophysics, reverse saturable absorption, and photodynamic therapeutic effect of six cationic biscyclometalated Ir(iii) complexes (1-6) with extended π-conjugation on the diimine ligand and/or the cyclometalating ligands are reported in this paper. All complexes possess ligand-localized 1π,π? absorption bands below 400 nm and charge-transfer absorption bands above 400 nm. They are all emissive in the 500-800 nm range in deoxygenated solutions at room temperature. All complexes exhibit strong and broad triplet excited-state absorption at 430-800 nm, and thus strong reverse saturable absorption for ns laser pulses at 532 nm. Complexes 1-4 are strong reverse saturable absorbers at 532 nm, while complex 6 could be a good candidate as a broadband reverse saturable absorber at 500-850 nm. The degree of π-conjugation of the diimine ligand mainly influences the 1π,π? transitions in their UV-vis absorption spectra, while the degree of π-conjugation of the cyclometalating ligand primarily affects the nature and energies of the lowest singlet and emitting triplet excited states. However, the lowest-energy triplet excited states for complexes 3-6 that contain the same benzo[i]dipyrido[3,2-a:2′,3′-c]phenazine (dppn) diimine ligand but different cyclometalating ligands remain the same as the dppn ligand-localized 3π,π? state, which gives rise to the long-lived, strong excited-state absorption in the visible to the near-IR region. All of the complexes exhibit a photodynamic therapeutic effect upon visible or red light activation, with complex 6 possessing the largest phototherapeutic index reported to date (>400) for an Ir(iii) complex. Interactions with biological targets such as DNA suggest that a novel mechanism of action may be at play for the photosensitizing effect. These Ir(iii) complexes also produce strong intracellular luminescence that highlights their potential as theranostic agents.
- Wang, Chengzhe,Lystrom, Levi,Yin, Huimin,Hetu, Marc,Kilina, Svetlana,McFarland, Sherri A.,Sun, Wenfang
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- Design and construction of copper(I) complexes based on flexi-dentate cyclic N2-donor Schiff bases via in situ reduction of copper(II) precursors
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Three copper(I) complexes [Cu(μ2-L1)I]n (1), [CuL1(μ-1,1,3-SeCN)]n (2) and [Cu 2(μ2-I)2(L2)2] (3), where L1 = 5,6-diphenyl-2,3-dihydro
- Jana, Subrata,Chattopadhyay, Shouvik
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- H3PW12O40/MCM-41 nanoparticles as efficient and reusable solid acid catalyst for the synthesis of quinoxalines
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The condensation reaction of 1,2-diketones and o-phenylenediamines was investigated in the presence of nano-sized mesoporous silica (MCM-41) supported 12-tungstophosphoric acid (TPA) as solid acid catalyst. Nano-sized MCM-41 was synthesized and the catalysts with different loading amounts of TPA (5-15 wt.%) were prepared and characterized by XRD, FT-IR and SEM techniques. The results confirm good dispersion of TPA on the solid support. The catalyst is reusable many times without loss in its activity.
- Abdollahi-Alibeik, Mohammad,Heidari-Torkabad, Ezzat
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- Synthesis, structures, and DFT study of CuBr based coordination polymers via in situ reduction of copper(II)
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This paper describes the one-pot synthesis of two CuBr based coordination polymers, {[Cu(??2-L1)Br]?·1.87H2O}n (1) and {[Cu(??2-L2)Br]?·C4H10O}n (2), where
- Jana, Subrata,Harms, Klaus,Bauz??, Antonio,Frontera, Antonio,Chattopadhyay, Shouvik
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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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- Preparation and Application of α-Imino Ketones through One-Pot Tandem Reactions Based on Heyns Rearrangement
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α-Imino ketone is a useful building block for the preparation of α-amino ketones and α-amino alcohols. However, its preparation has been seldomly seen. Herein, a metal-free and operationally simple strategy has been developed to generate α-imino ketones with high regioselectivity. Meanwhile, the method allowed for the preparation of various N,O-ketals with high regioselectivities and diastereoselectivities through cascade reactions in one pot.
- Li, Ling,Zhang, Shiqi,Deng, Xiongfei,Li, Guangxun,Tang, Zhuo,Zhao, Gang
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supporting information
p. 6819 - 6824
(2021/09/08)
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- HBTU-catalyzed simple and mild protocol for the synthesis of quinoxaline derivatives
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HBTU-catalyzed, simple, mild, and effective protocol for the synthesis of quinoxalines has been established. The reaction between 1,2-diamines, benzil, and catalytic amount of HBTU in ethanol resulted into quinoxalines. Various aliphatic, aromatic and het
- Bhushan, B. Popatkar,Gangadhar, A. Meshram
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- Dowex 50W: Mild efficient reusable heterogeneous catalyst for synthesis of quinoxaline derivatives in aqueous medium
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An efficient, simple and eco-friendly procedure is reported in presence of heterogeneous Dowex 50W catalyst in aqueous medium under refluxing condition to produce quinoxaline derivatives. Catalyst has participated in condensation reaction between 1,2-diamines and various aromatic 1,2-diketones smoothly with excellent yield of the products in short reaction times. Dowex 50W was used more than five times in this reaction separately and showed an excellent recyclability throughout the reaction.(figure presented).
- Datta, Arup,Halder, Samiran
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p. 1218 - 1224
(2021/02/09)
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- A general and inexpensive protocol for the nanomagnetic 5-sulfosalicylic acid catalyzed the synthesis of tetrahydrobenzo[b]pyrans and quinoxaline derivatives
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In this study, a novel acid-functionalized magnetic nanoparticles with high loaded multifunctional acidic groups was fabricated by anchoring water-soluble 5-sulfosalicylic acid onto the surface silica-modified Fe3O4. The magnetically recyclable Fe3O4@SiO2@5-SA (20?mg) showed excellent reactivity for greener synthesis of tetrahydrobenzo[b]pyrans via a three-component reaction of different aromatic aldehydes, malononitrile and dimedone in good to excellent yields (70–95percent) in pure water at short reaction times (40–150?min). The method shows eco-friendly synthesis of quinoxaline derivatives from direct condensation of substituted 1,2-diamine with various 1,2-dicarbonyl in ethanol at room temperature to afford the desired quinoxalines with good to excellent yields (60–97percent) at shorter reaction times (120–240?min). The morphology and magnetic properties of MNPs were studied with scanning electron microscopy, X-ray powder diffraction, Fourier translation infrared spectroscopy, vibrating sample magnetometer and thermogravimetric. The results showed that the Fe3O4@SiO2@5-SA catalyst is completely recoverable by an external magnet and retained catalytic activity after five recycles.
- Saboury, Farzaneh,Azizi, Najmedin,Mirjafari, Zohreh,Mahmoudi Hashemi, Mohammad
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p. 2533 - 2543
(2020/05/18)
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- Porous carbons-derived from vegetal biomass in the synthesis of quinoxalines. Mechanistic insights
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We report herein for the first-time acid biomass-derived carbons from vegetal biomass, with high developed porosity, prepared through integrating method comprising pyrolysis and surface phosphonation, able to efficiently catalyze the synthesis of quinoxalines from 1,2-diamines and α-hydroxi ketones, under aerobic conditions. The obtained results indicate that the reaction is mainly driven by a combination of acid function strength and textural properties in terms of conversion and selectivity. Furthermore, our experimental and theoretical observations suggest that the preferred reaction pathway for this transformation, in the presence of the investigated acid carbon catalysts, involves cascade reactions including imination reaction between reactants, successive imine-enamine and keto-enol tautomerisms, heterocyclization followed by dehydration, and aromatization. While the acid sites seem to be a relevant role in each reaction step, the system formed by activated carbon and molecular oxygen could be behind the last oxidative reaction to give the corresponding nitrogen heterocycles.
- Godino-Ojer,Blazquez-García,Matos,Bernardo,Fonseca,Pérez Mayoral
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- BiCl3-modified perlite as an effective catalyst for selective organic transformations: a green protocol
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A new perlite supported Bismuth Chloride (BiCl3) was used as an efficient heterogeneous catalyst for the synthesis of heterocyclic compounds viz., quinoxalines and dihydropyrimidinones. Fourier-transform infrared spectroscopy (FT–IR), scanning
- Brindha, Kannan,Amutha, Parasuraman,Krishnakumar, Balu,do Nascimento Sobral, Abílio José Fraga
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p. 4367 - 4381
(2019/05/15)
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- Method for manufacturing triarylpyrazine derivative
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A novel synthesis method of a triarylpyrazine derivative, in particular, a manufacturing method by which a triarylpyrazine derivative, in specific, a 2,3,5-triarylpyrazine derivative in which an aryl group at a 5-position includes a substituent having an electron-withdrawing property can be synthesized with high yield as compared to a conventional method is provided. By using a synthesis method in which a mixture including a 1-aryl-2-(methylsulfinyl)ethanone derivative, meso-1,2-diarylethylenediamine, and a dehydrogenation agent is irradiated with a microwave to be reacted, the above object is achieved.
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Paragraph 0137-0140; 0142
(2016/11/17)
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- Fe3O4@SiO2-imid-PMAn magnetic porous nanosphere as recyclable catalyst for the green synthesis of quinoxaline derivatives at room temperature and study of their antifungal activities
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An efficient, simple, and green procedure for the synthesis of quinoxaline derivatives catalyzed by Fe3O4@SiO2-imid-PMAn nanoparticles at room temperature is described. This environmentally benign method provides several advantages such as mild reaction conditions, good to excellent yields, short reaction times, simple work-up and catalyst stability, easy preparation, heterogeneous nature and easy separation of the catalyst. Also, nanocatalyst can be easily recovered by a magnetic field and reused for the next reactions for at least 6 times without distinct deterioration in catalytic activity. SEM, BET, DLS and leaching of catalyst after each reaction cycle were investigated. Furthermore, antifungal activity of various derivatives against three phytopathogenic fungi (Alternaria alternata, Pyricularia oryzae, and Alternaria brassicae) was investigated.
- Javidi, Jaber,Esmaeilpour, Mohsen
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p. 409 - 422
(2015/10/28)
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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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- 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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p. 422 - 433
(2016/07/06)
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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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- Aqueous hydrofluoric acid catalyzed facile synthesis of 2,3,6-substituted quinoxalines
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A versatile synthetic route for the preparation of 2,3,6-trisubstituted quinoxalines in excellent yield is developed from θ-diamines and 1,2-dicarbonyl compounds in which aqueous hydrofluoric acid was employed as the medium and catalyst. Other salient features of this protocol include milder conditions, absence of coupling agents, and easy workup procedures.
- Chandra Shekhar,Ravi Kumar,Sathaiah,Raju,Srinivas,Shanthan Rao,Narsaiah
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p. 1504 - 1508
(2015/04/27)
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- Copper-catalyzed synthesis of valuable heterocyclic compounds using a tandem oxidation process approach
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The synthesis of quinoxalines via a tandem oxidation process using a copper acetate monohydrate/2,2,6,6-tetramethylpiperidine N-oxyl (TEMPO) oxidative system has been described. Using this approach, a series of quinoxaline derivatives were formed in good yields within short reaction times under microwave irradiation. The oxidative system was also extended to the selective synthesis of dihydropyrazines and pyrazines.
- Jeena, Vineet,Sithebe, Siphamandla,Robinson, Ross S.
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supporting information
p. 1484 - 1491
(2015/05/20)
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- An iron Schiff base complex loaded mesoporous silica nanoreactor as a catalyst for the synthesis of pyrazine-based heterocycles
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An iron Schiff base complex was encapsulated in SBA-15 mesoporous silica to afford a Fe(III)-Schiff base/SBA-15 heterogeneous nanocatalyst for the synthesis of pyridopyrazine and quinoxaline heterocycles. These reactions proceeded in water with excellent yields. The catalyst was characterized by physico-chemical and spectroscopic methods and found to retain the characteristic channel structures of the SBA-15, allowing good accessibility of the encapsulated metal complex.
- Malakooti, Reihaneh,Bardajee, Ghasem Rezanejade,Hadizadeh, Somayyeh,Atashin, Hassan,Khanjari, Hadiseh
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- Pentafluorophenylammonium triflate: A highly efficient catalyst for the synthesis of quinoxaline derivatives in water
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A simple, inexpensive, environmentally friendly and efficient route for the rapid and efficient synthesis of quinoxaline derivatives using pentafluorophenylammonium triflate (PFPAT) as a catalyst is described. Various quinoxaline derivatives were synthesi
- Khaksar, Samad,Radpeyma, Hanieh
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p. 1023 - 1027
(2014/12/10)
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- A highly efficient procedure for the synthesis of quinoxaline derivatives using polyvinylpolypyrrolidone supported triflic acid catalyst (PVPP·OTf)
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A polyvinylpolypyrrolidone supported triflic acid was shown to be useful as a recyclable heterogeneous catalyst for the rapid and efficient synthesis of quinoxaline derivatives in good-to-excellent yields. The catalyst is easily prepared, air-stable, reus
- Khaksar, Samad,Tajbakhsh, Mahmoud,Gholami, Milad,Rostamnezhad, Fariba
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p. 1287 - 1290
(2014/10/15)
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- An environmentally friendly, cost effective synthesis of quinoxalines: The influence of microwave reaction conditions
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A convenient, environmentally friendly and novel synthesis of quinoxalines using silica gel as the catalyst is described. The choice of microwave conditions has been shown to have a substantial impact on the reaction outcome with closed-vessel microwave irradiation resulting in the formation of quinoxalines in high yields and short reaction times. Preliminary mechanistic investigations have indicated that a slight build-up in pressure has a major impact on the reaction outcome.
- Jeena, Vineet,Robinson, Ross S.
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supporting information
p. 642 - 645
(2014/01/23)
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- YbCl3-catalyzed one-pot synthesis of dihydropyrazines, piperazines, and pyrazines
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A simple and efficient synthetic approach to dihydropyrazines via YbCl 3-catalyzed reaction of α-hydroxyketones with diamines under mild conditions was developed. The corresponding 2,3-subsitituted piperazines and pyrazines were obtained through tandem conversion of dihydropyrazines with good yields.
- Fan, Liyan,Chen, Wen,Qian, Changtao
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p. 231 - 234
(2013/02/23)
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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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- ZrOCl2.8H2O in water: An efficient catalyst for rapid one-pot synthesis of pyridopyrazines, pyrazines and 2,3-disubstituted quinoxalines
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Zirconium(IV) oxide chloride was found to be a rapid and efficient catalyst for the synthesis of pyrazines and 2,3-disubstituted quinoxalines in water. A variety of pyridopyrazine and 2,3-disubstituted quinoxaline derivatives are readily prepared in high yields under green conditions by cyclocondensation of the desired 1,2-diamine and 1,2-diketone using a catalytic amount of zirconium(IV) oxide chloride in water. Less active diamines, such as 2,3- and 3,4-diaminopyridines took part in this protocol to provide the desired products in good to excellent yields.
- Bardajee, Ghasem Rezanejade
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p. 872 - 877
(2013/10/22)
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- Graphite catalyzed green synthesis of quinoxalines
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A new simple approach using environmentally benign, cheap, and easily recyclable graphite as a heterogeneous catalyst for the synthesis of quinoxalines is described. A library of pharmacologically interesting diphenylquinoxalines is prepared by the double condensation of substituted benzils, phenanthrene-9,10-dione, and benzoin with aromatic diamines in 71-93% yields at room temperature in ethanol. Aliphatic diamines gave corresponding dihydropyrazines from substituted benzils in 72-92% yields.
- Kadam, Hari K.,Khan, Salman,Kunkalkar, Rupesh A.,Tilve, Santosh G.
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p. 1003 - 1007
(2013/02/25)
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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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- Covalent anchoring of copper-Schiff base complex into SBA-15 as a heterogeneous catalyst for the synthesis of pyridopyrazine and quinoxaline derivatives
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The ordered mesoporous silica SBA-15 was covalently anchored with copper (II) Schiff base complex to afford Cu(II)-Schiff base/SBA-15 catalyst. Powder X-ray diffraction, nitrogen adsorption-desorption analyses and TEM image confirm not only the retaining of support properties after anchoring but also the existence of void space in nanometer scale which result in good catalytic activity in the synthesis of pyridopyrazine and quinoxaline derivatives.
- Bardajee, Ghasem Rezanejade,Malakooti, Reihaneh,Jami, Fereshteh,Parsaei, Zeinab,Atashin, Hassan
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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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- 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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- A recyclable solid acid catalyst sulfated titania for easy synthesis of quinoxaline and dipyridophenazine derivatives under microwave irradiation
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TiO2SO42, prepared by solgel method has been used for the synthesis of quinoxaline and dipyridophenizine derivatives under microwave irradiation. High-resolution transmission electron microscope (HR-TEM) and atomic force m
- Krishnakumar, Balu,Swaminathan, Meenakshisundaram
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experimental part
p. 1261 - 1266
(2012/01/31)
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- Polyethylene glycol in water: A simple, efficient and green protocol for the synthesis of quinoxalines
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A variety of biologically important quinoxaline derivatives has been efficiently synthesized in excellent yields under extremely mild conditions using PEG-600 and water. This inexpensive, non-toxic, ecofriendly and readily available system efficiently condensed several aromatic as well as aliphatic 1,2-diketones with aromatic and aliphatic 1,2-diamines to afford the products in excellent yield. Polyethylene glycol (PEG) can be recovered and recycled. Indian Academy of Sciences.
- Chavan, Hemant V.,Adsul, Laxman K.,Bandgar, Babasaheb P.
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experimental part
p. 477 - 483
(2012/03/26)
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- Solvent free synthesis of quinoxalines, dipyridophenazines and chalcones under microwave irradiation with sulfated Degussa titania as a novel solid acid catalyst
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Sulfated TiO2-P25 (Degussa titania) has been prepared by sol-gel method using H2SO4 and characterized by FT-IR, XRD, FE-SEM, EDS, HR-TEM, XPS, DRS and BET surface area measurements. Sulfate loading by H2SO4 increases the Lewis acidity of Degussa tiatania. This catalyst gives an excellent yield with less reaction time and is an inexpensive and easily recyclable solid acid catalyst for the synthesis of quinaxalines, dipyridophenazines and chalcones under microwave irradiation.
- Krishnakumar,Swaminathan
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experimental part
p. 16 - 25
(2011/12/14)
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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
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experimental part
p. 2053 - 2063
(2011/07/07)
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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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experimental part
p. 2047 - 2056
(2010/08/13)
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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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- A recyclable and highly effective sulfated TiO2-P25 for the synthesis of quinoxaline and dipyridophenazine derivatives at room temperature
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Sulfated TiO2-P25 has been prepared using H2SO 4 and used for the synthesis of quinoxaline and dipyridophenazine derivatives. Sulfate loading by H2SO4 increases the Lewis acidity of TiO2-P2
- Krishnakumar,Swaminathan
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experimental part
p. 2572 - 2577
(2010/11/18)
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- Application of metalloporphyrins as new catalysts for the efficient, mild and regioselective synthesis of quinoxaline derivatives
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A simple, highly efficient and green procedure for the condensation of aryl and alkyl 1,2-diamines with α-diketones in the presence of catalytic amounts of metalloporphyrins at room temperature is described. Using this method, quinoxaline derivatives as biologically interesting compounds are produced in high to excellent yields and short reaction times. In this report, the effects of central metal in porphyrin core and substituents on tetraphenylporphyrin skeleton have been studied.
- Mohammadi, Khosro,Hasaninejad, Alireza,Niad, Mahmud,Najmi, Mojtaba
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experimental part
p. 1052 - 1058
(2011/11/14)
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- Reactions of 1,2,5-thiadiazole 1,1-dioxide derivatives with nitrogen nucleophiles. Part IV. Addition of α-diamines
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α-diamines, such as ethylendiamine and o-phenylendiamine, add to 3,4-aryl-disubstituted 1,2,5-thiadiazole 1,1-dioxides to give dihydropyrazines or quinoxalines, respectively and sulfamide. The new compound acenaphtho [5,6-b]-2,3-dihydropyrazine was synthesized and characterized. The addition of ethylendiamine to 3,4-diphenyl-1,2,5-thiadiazoline 1,1-dioxide gives 3,4-disubstituted thiadiazolidlne 1,1-dioxide, dihydropyrazines, or pyrazines, depending on the reaction condition used. The reactions were followed by cyclic voltammetry and NMR spectroscopy which, in some cases, allowed the detection of the thiadiazolidine intermediate. Copyright
- Mirifico, Maria Virginia,Caram, Jose Alberto,Vasini, Enrique Julio,Piro, Osear Enrique,Castellano, Eduardo E.
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experimental part
p. 163 - 169
(2010/04/30)
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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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experimental part
p. 569 - 579
(2009/09/05)
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- Novel orange-red light-emitting polymers with cyclometaled iridium complex grafted in alkyl chain
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Novel poly(fluorene-alt-carbazole) (PFCz) based copolymers with 3,6-carbazole-N-alkyl grafted iridium complex using 2,3-diphenylpyrazine as ligand (IrBpz) were synthesized by Suzuki polycondensation. The emission of host polymer, PFCz, was completely quen
- Ying, Lei,Zou, Jianhua,Zhang, Anqi,Chen, Bing,Yang, Wei,Cao, Yong
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experimental part
p. 2727 - 2734
(2009/12/06)
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- Organometallic complex and light emitting element, light emitting device, and electronic device using the organometallic complex
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To provide an organometallic complex by which red-color light emission can be obtained. In addition, to provide an organometallic complex with high light emission efficiency. Further, to provide an organometallic complex by which red-color light emission with high luminous efficiency can be obtained. An organometallic complex having a structure represented by the following general formula (G1) is provided. (In the formula, A represents an aromatic hydrocarbon group having 6 to 25 carbon atoms. Further, Z represents any one of hydrogen, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or an aryl group having 6 to 25 carbon atoms. In addition, Ar1 represents an aryl group having 6 to 25 carbon atoms. R1 represents any one of hydrogen, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms. Further, M is a central metal and represents an element belonging to Group 9 or Group 10.)
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