- 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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- Method for synthesizing quinoxaline compound under visible light induced iron catalysis condition
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The invention belongs to the technical field of compound synthesis, and particularly relates to a method for synthesizing quinoxaline compounds under visible light induced iron catalysis conditions. The method comprises the following steps: by taking non-activated aliphatic amine and o-phenylenediamine as raw materials, under the action of a photosensitizer, under the illumination of visible light, reacting in a solvent at room temperature and under oxygen conditions to generate the quinoxaline compound. The method has better substrate universality and relatively mild reaction conditions, not only realizes synthesis of the quinoxaline compound for the first time, but also widens the field of organic synthesis.
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Paragraph 0042-0047
(2021/07/10)
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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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- Nickel(ii)-catalyzed addition of aryl-, alkenyl-, and alkylboronic acids to alkenylazaarenes
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A nickel(II)-catalyzed addition of aryl-, alkenyl-, and alkylboronic acids to alkenylazaarenes was presented. This reaction exhibited high efficiency (up to 93% yield), a broad substrate scope (seven types of heterocycles), and good functional group compatibility. The resulting products can be further transformed to many useful building blocks. Finally, the preliminary studies suggested that the adjacent N atom of the heterocycles was essential for the high reactivity.
- Liu, Xing-Yu,Tan, Yun-Xuan,Wang, Xin,Xu, Hao,Wang, Yu-Hui,Tian, Ping,Lin, Guo-Qiang
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supporting information
p. 4038 - 4042
(2020/05/18)
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- Radical C?H Acylation of Nitrogen Heterocycles Induced by an Aerobic Oxidation of Aldehydes
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An aerobic radical approach for the synthesis of unsymmetrical heteroaryl ketones is described herein. The reaction involves cross-dehydrogenative coupling between aldehydes and heteroaromatic bases with molecular oxygen (O2). The key aspect of the method is the generation of reactive acyl radical via homolytic activation of aldehyde C?H bond using O2 as the sole oxidant. The reaction has a good substrate scope with respect to aldehydes and functionalized nitrogen heterocycles. Based on our mechanistic studies, a radical chain pathway is suggested for the reaction. A synthetic application of the method is demonstrated in the formal synthesis of natural alkaloid (±) angustureine.
- Paul, Subhasis,Bhakat, Manotosh,Guin, Joyram
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supporting information
p. 3154 - 3160
(2019/08/30)
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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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- 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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- Two New Furans from the Brown Alga Acrocarpia paniculata: the Use of 4-Phenyl-4H-1,2,4-triazoline-3,5-dione to Determine the Substitution Pattern of a Furan
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The dichloromethane-soluble extract of the brown alga Acrocarpia paniculata has yielded two homologous branched chain lipids containing a furan ring.Reaction of a substituted furan with 4-phenyl-4H-1,2,4-triazoline-3,5-dione to yield an alkyl 2-ene-1,4-dione was used to determine the orientation of substituents on a 2,3,5-substituted furan
- Kazlauskas, Rymantas,Murphy, Peter T.,Wells, Robert J.,Gregson, Richard P.
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p. 165 - 170
(2007/10/02)
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