- 4-(2,2-dimethyldioxalan-4-yl)-5-(quinoxalin-2-yl)-1,3-dithiol-2-one, a proligand relating to the cofactor of the oxomolybdoenzymes
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The coupling of 2-iodoquinoxaline to 4-(2,2-dimethyl-1,3-dioxolan-4- yl)-5-(tri-n-butylstannyl)-1,3-dithiol-2-one 5 gave 4-(2,2-dimethyl-1,3- dioxolan-4-yl)-5-(quinoxalin-2-yl)-1,3-dithiol-2-one 4.
- Dinsmore, Andrew,Garner, C. David,Joule, John A.
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- Tetrabutylammonium Bromide-Catalyzed Transfer Hydrogenation of Quinoxaline with HBpin as a Hydrogen Source
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A metal-free environmentally benign, simple, and efficient transfer hydrogenation process of quinoxaline has been developed using the HBpin reagent as a hydrogen source. This reaction is compatible with a variety of quinoxalines offering the desired tetrahydroquinoxalines in moderate-to-excellent yields with Bu4NBr as a noncorrosive and low-cost catalyst.
- Guo, Qi,Chen, Jingchao,Shen, Guoli,Lu, Guangfu,Yang, Xuemei,Tang, Yan,Zhu, Yuanbin,Wu, Shiyuan,Fan, Baomin
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p. 540 - 546
(2021/12/27)
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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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- Hydrogen Auto-transfer Synthesis of Quinoxalines from o-Nitroanilines and Biomass-based Diols Catalyzed by MOF-derived N,P Co-doped Cobalt Catalysts
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A Co-based heterogeneous catalyst supported on N,P co-doped porous carbon (Co@NCP) is prepared via a facile in-situ doping-carbonization method. The Co@NCP composite features a large surface area, high pore volume, high-density and strong basic sites. Furthermore, doping of P atoms can regulate the electronic density of Co. Therefore, Co@NCP exhibits good performance for the synthesis of quinoxalines from o-nitroanilines and biomass-derived diols under alkali-free conditions.
- Sun, Kangkang,Li, Dandan,Lu, Guo-Ping,Cai, Chun
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p. 373 - 381
(2020/12/09)
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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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- Manganese(I)-Catalyzed Sustainable Synthesis of Quinoxaline and Quinazoline Derivatives with the Liberation of Dihydrogen
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Direct synthesis of N-heterocycles via the acceptorless dehydrogenative coupling is very challenging and scarcely reported under 3d transition-metal catalysis. Here, we have developed an efficient Mn(I)-catalyzed sustainable synthesis of various quinoxalines from 1,2-diaminobenzenes and 1,2-diols via the acceptorless dehydrogenative coupling reaction. Further, this strategy was successfully applied for the unprecedented synthesis of quinazolines by the reaction of 2-aminobenzyl alcohol with primary amides. The present protocol provides an atom-economical and sustainable route for the synthesis of various quinoxaline and quinazoline derivatives by employing an earth-abundant manganese salt and simple phosphine-free NNN-tridentate ligand.
- Mondal, Akash,Sahoo, Manoj Kumar,Subaramanian, Murugan,Balaraman, Ekambaram
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p. 7181 - 7191
(2020/07/21)
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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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- Synthesis of Pyrazines and Quinoxalines via Acceptorless Dehydrogenative Coupling Routes Catalyzed by Manganese Pincer Complexes
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Base-metal catalyzed dehydrogenative self-coupling of 2-amino alcohols to selectively form functionalized 2,5-substituted pyrazine derivatives is presented. Also, 2-substituted quinoxaline derivatives are synthesized by dehydrogenative coupling of 1,2-diaminobenzene and 1,2-diols. In both cases, water and hydrogen gas are formed as the sole byproducts. The reactions are catalyzed by acridine-based pincer complexes of earth-abundant manganese.
- Daw, Prosenjit,Kumar, Amit,Espinosa-Jalapa, Noel Angel,Diskin-Posner, Yael,Ben-David, Yehoshoa,Milstein, David
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p. 7734 - 7741
(2018/08/03)
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- C-N Bond Formation Catalyzed by Ruthenium Nanoparticles Supported on N-Doped Carbon via Acceptorless Dehydrogenation to Secondary Amines, Imines, Benzimidazoles and Quinoxalines
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Ruthenium nanoparticles (NPs) supported on N-doped carbon (Ru/N?C) were prepared by the pyrolysis of cis-Ru(phen)2Cl2 loaded onto carbon powder (VULCAN XC72R) at 800 °C. Ru/N?C NPs (0.2 mol% Ru) selectively catalyzed either acceptorless dehydrogenation coupling (ADC) or auto-transfer-hydrogen (ATH) reactions of amines with alcohols to imines and secondary amines. Such selectivity could be controlled by the choice of alkali metal ion associated with the base. Under similar catalytic conditions, the ADC cross-coupling of diamines with primary alcohols or diols afforded the corresponding benzimidazoles and quinoxalines in good to excellent yields. This catalytic system displayed good activity, recyclability, and wide applicability to a diverse range of substrates.
- Guo, Bin,Li, Hong-Xi,Zhang, Shi-Qi,Young, David James,Lang, Jian-Ping
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p. 5627 - 5636
(2018/12/04)
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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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- The synthesis of benzimidazoles and quinoxalines from aromatic diamines and alcohols by iridium-catalyzed acceptorless dehydrogenative alkylation
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Benzimidazoles and quinoxalines are important N-heteroaromatics with many applications in pharmaceutical and chemical industry. Here, the synthesis of both classes of compounds starting from aromatic diamines and alcohols (benzimidazoles) or diols (quinoxalines) is reported. The reactions proceed through acceptorless dehydrogenative condensation steps. Water and two equivalents of hydrogen are liberated in the course of the reactions. An Ir complex stabilized by the tridentate P^N^P ligand N2,N 6-bis(di-isopropylphosphino)pyridine-2,6-diamine revealed the highest catalytic activity for both reactions. Aromatic diamines were reacted with alcohols and diols to form benzimidazoles or quinoxalines, respectively (see scheme). In the course of the reactions, water and two equivalents of hydrogen gas were eliminated/liberated. An Ir complex stabilized by a tridentate PNP ligand was found to be an efficient catalyst in these reactions.
- Hille, Toni,Irrgang, Torsten,Kempe, Rhett
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supporting information
p. 5569 - 5572
(2014/05/20)
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- Biomass into chemicals: One-pot two- and three-step synthesis of quinoxalines from biomass-derived glycols and 1,2-dinitrobenzene derivatives using supported gold nanoparticles as catalysts
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An efficient and selective one-pot two-step method, for the synthesis of quinoxalines by oxidative coupling of vicinal diols with 1,2-phenylenediamine derivatives, has been developed by using gold nanoparticles supported on nanoparticulated ceria (Au/CeO2) or hydrotalcite (Au/HT) as catalysts and air as oxidant, in the absence of any homogeneous base. Reaction kinetics shows that the reaction controlling step is the oxidation of the diol to α-hydroxycarbonyl compound. Furthermore, a one-pot three-step synthesis of 2-methylquinoxaline starting from 1,2-dinitrobenzene and 1,2-propanediol has been successfully carried out with 98% conversion and 83% global yield to the final product.
- Climent,Corma,Hernandez,Hungria,Iborra,Martinez-Silvestre
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p. 118 - 129
(2012/10/08)
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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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- Asymmetric hydrogenation of quinoxalines catalyzed by iridium/PipPhos
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A catalyst made in situ from the (cyclooctadiene)iridium chloride dimer, [Ir(COD)Cl]2, and the monodentate phosphoramidite ligand (S)-PipPhos was used in the enantioselective hydrogenation of 2- and 2,6-substituted quinoxalines. In the presence
- Mrsic, Natasa,Jerphagnon, Thomas,Minnaard, Adriaan J.,Feringa, Ben L.,De Vries, Johannes G.
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experimental part
p. 2549 - 2552
(2009/12/27)
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- Inhibitors of cholesteryl ester transfer protein
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This invention relates to inhibitors of CETP and methods for producing these inhibitors. The invention also provides pharmaceutical compositions comprising the inhibitors of the invention and methods of utilizing the inhibitors and pharmaceutical compositions in the treatment and prevention of various disorders mediated by CETP.
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Page/Page column 16-17
(2010/02/15)
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- v-Triazolines. Part 34. Thermal Behavior of 1-(2-Aminophenyl)-4,5-dihydro-5-morpholino-1,2,3-triazoles: New Synthesis of 2-Alkylquinoxalines
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4,5-Dihydro-5-morpholino-1-(2-nitrophenyl)-1,2,3-triazoles 4 are prepared by reaction of an aldehyde with morpholine and the appropriate aryl azide.On reduction 1-(2-aminophenyl)-4,5-dihydro-5-morpholino-1,2,3-triazoles 5 are formed.Thermal rearrangement of compounds 5 affords unstable 2-alkyl-3-amino-1,2,3,4-tetrahydroquinoxalines 7, which undergo deamination to 2-alkyl-1,2-dihydroquinoxalines 8.Oxidation of these affords 2-alkylquinoxalines 10.The mechanism of thermal the rearrangement of triazoles 5 is investigated and discussed.
- Battistini, Maurizio,Erba, Emanuela,Pocar, Donato
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p. 339 - 342
(2007/10/02)
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- ALKYLATION OF HETEROARYL ALKYL METALS BY BISTRIALKYLSILYLPEROXIDES
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Heteroaryl alkyl metals 3 undergo methylation and ethylation upon treatment with bistrimethylsilylperoxide 1a and bistriethylsilylperoxide 1b.Benzothiazolylderivatives 3c-d and 3h-j react with 1a giving trimethylsilyloxylation other than methylation products.The reaction of 3a-b with 1a leads also to the trimethylsilylation product 5.The reaction of 3g, 3c and 3k with 1b provides the ethylated derivatives 2h, 2d and 2n respectively.No reaction occurred when 3c was treated with 1c.
- Epifani, Erbana,Florio, Saverio,Troisi, Luigino
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p. 4031 - 4038
(2007/10/02)
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