- Electro-reductive C-H cyanoalkylation of quinoxalin-2(1H)-ones
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Herein, we report a practical electro-reductive protocol for the direct C–H cyanoalkylation of quinoxalin-2(1H)-ones via iminyl radical-mediated ring opening. These mild reactions proceed under metal-, reductant-, and reagent-free conditions to provide synthetically useful cyanoalkylated quinoxalin-2(1H)-ones.
- Ding, Ling,Liu, Yuxiu,Niu, Kaikai,Wang, Qingmin
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supporting information
(2022/01/24)
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- Photoinitiated Multicomponent Anti-Markovnikov Alkoxylation over Graphene Oxide
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The development of graphene oxide–based heterogeneous materials with an economical and environmentally–friendly manner has the potential to facilitate many important organic transformations but proves to have few relevant reported reactions. Herein, we explore the synergistic role of catalytic systems driven by graphene oxide and visible light that form nucleophilic alkoxyl radical intermediates, which enable an anti-Markovnikov addition exclusively to the terminal alkenes, and then the produced benzyl radicals are subsequently added with N–methylquinoxalones. This photoinduced cascade radical difunctionalization of olefins offers a concise and applicable protocol for constructing alkoxyl–substituted N–methylquinoxalones.
- He, Haiping,Hu, Jian,Huang, Qing,Li, Fan,Liu, Liangxian,Nie, Liang,Peng, Xiangjun,Yang, Ming,Yao, Zhiyang,Zhou, Linyi
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supporting information
(2022/01/20)
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- N, N, N', N'-Tetramethylethylenediamine-Enabled Photoredox-Catalyzed C-H Methylation of N-Heteroarenes
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Aiming at the valuable methylation process, readily available and inexpensive N,N,N′,N′-tetramethylethylenediamine (TMEDA) was first identified as a new methyl source in photoredox-catalyzed transformation in this work. By virtue of this simple methylating reagent, a facile and practical protocol for the direct C-H methylation of N-heteroarenes was developed, featuring mild reaction conditions, broad substrate scope, and scalability. Mechanistic studies disclosed that a sequential photoredox, base-assisted proton shift, fragmentation, and tautomerization process was essentially involved.
- Liu, Fang,Ye, Zhi-Peng,Hu, Yuan-Zhuo,Gao, Jie,Zheng, Lan,Chen, Kai,Xiang, Hao-Yue,Chen, Xiao-Qing,Yang, Hua
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p. 11905 - 11914
(2021/08/24)
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- Visible Light-Promoted Radical Relay Cyclization/C-C Bond Formation of N-Allylbromodifluoroacetamides with Quinoxalin-2(1 H)-ones
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A visible light-promoted radical relay of N-allylbromodifluoroacetamide with quinoxalin-2(1H)-ones was developed in which 5-exo-trig cyclization and C-C bond formation were involved. This protocol was performed under mild conditions to facilely offer a variety of hybrid molecules bearing both quinoxalin-2(1H)-one and 3,3-difluoro-γ-lactam motifs. These prepared novel skeletons would expand the accessible chemical space for structurally complex heterocycles with potential biological activities.
- Ye, Zhi-Peng,Liu, Fang,Duan, Xin-Yu,Gao, Jie,Guan, Jian-Ping,Xiao, Jun-An,Xiang, Hao-Yue,Chen, Kai,Yang, Hua
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p. 17173 - 17183
(2021/11/18)
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- Method for catalytically preparing 3-sulfur substituted quinoxalinone derivative
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The invention relates to a method for catalytically preparing a 3-sulfur substituted quinoxalinone derivative. The method comprises the following steps of: firstly preparing a 3-(thiophenyl) quinoxaline-2 (1H)-ketone derivative, then adding the 3-(thiophenyl) quinoxaline-2 (1H)-ketone derivative, disulfide, an oxidizing agent and a catalyst into a reaction container, adding a solvent, reacting under the light irradiation of a blue lamp, and after the reaction is completed, filtering, extracting, concentrating, separating and purifying to obtain the 3-sulfur substituted quinoxalinone derivative. According to the invention, the problem that a traditional catalyst needs high-temperature reaction is solved, disulfide is used as a raw material, the problem that foul thiophenol and thiol substances are used as raw materials traditionally is solved, and a green and efficient synthesis method is used to promote industrialization of a reaction system; and meanwhile, quinoxalinone compounds with different substituent groups are also efficiently expanded.
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Paragraph 0057; 0059
(2021/11/06)
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- C?H Methylation of Iminoamido Heterocycles with Sulfur Ylides**
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The direct methylation of N-heterocycles is an important transformation for the advancement of pharmaceuticals, agrochemicals, functional materials, and other chemical entities. Herein, the unprecedented C(sp2)-H methylation of iminoamido heterocycles as nucleoside base analogues is described. Notably, trimethylsulfoxonium salt was employed as a methylating agent under aqueous conditions. A wide substrate scope and excellent level of functional-group tolerance were attained. Moreover, this method can be readily applied to the site-selective methylation of azauracil nucleosides. The feasibility of gram-scale reactions and various transformations of the products highlight the synthetic potential of the developed method. Combined deuterium-labeling experiments aided the elucidation of a plausible reaction mechanism.
- Ghosh, Prithwish,Kwon, Na Yeon,Kim, Saegun,Han, Sangil,Lee, Suk Hun,An, Won,Mishra, Neeraj Kumar,Han, Soo Bong,Kim, In Su
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supporting information
p. 191 - 196
(2020/10/29)
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- Visible-Light-Promoted Switchable Synthesis of C-3-Functionalized Quinoxalin-2(1H)-ones
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A visible-light-promoted synthesis of quinoxalin-2(1H)-ones has been developed using 9-mesityl-10-methylacridinium perchlorate as an organo-photocatalyst. The atmosphere-controlled method (Ar/air) enabled the selective synthesis of hydroxyl- and acyl-containing quinoxalin-2(1H)-ones under mild reaction conditions without the use of any metal catalysts or toxic reagents. A fluorescent labelling experiment showed that hydroxyl-containing quinoxalin-2(1H)-ones may have utility in various biological applications as potent fluorophores. (Figure presented.).
- Aganda, Kim Christopher C.,Hong, Boseok,Lee, Anna
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supporting information
p. 1443 - 1448
(2021/01/26)
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- Simple and green synthesis of benzimidazoles and pyrrolo[1,2-: A] quinoxalines via Mamedov heterocycle rearrangement
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A method for the synthesis of coupling compounds of benzimidazoles and pyrrolo[1,2-a]quinoxalines via Mamedov Heterocycle Rearrangement is reported here. This method was conducted at room temperature and only solvent (HOAc) was required. A series of 4-(1H-benzo[d]imidazol-2-yl)pyrrolo[1,2-a]quinoxaline derivatives were obtained in moderate to good yields.
- Li, Shichen,Feng, Lei,Ma, Chen
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supporting information
p. 9320 - 9323
(2021/06/14)
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- Metal-Free Direct Oxidative C?N Bond Coupling of Quinoxalin-2(1H)-ones with Azoles under Mild Conditions
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Direct C3?H amination of quinoxalin-2(1H)-ones with azoles under mild conditions promoted by PIFA has been achieved in good yield in a very fast manner. Mechanistic study revealed that the reaction proceeds through a radical process. In addition, this method could be applied to gram-scale reaction.
- Cai, Yuepiao,Du, Xinyue,Guo, Jingwen,Xia, Qinqin,Zhang, Lina,Zhang, Liting
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supporting information
p. 2230 - 2238
(2021/07/22)
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- K2S2O8-catalyzed highly regioselective amidoalkylation of diverse N-heteroaromatics in water under visible light irradiation
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A K2S2O8-catalyzed versatile C(sp2)-C(sp3) bond formation with N-heteroaromatics and γ-lactams/amides was developed. Quinoxalin-2(1H)-one, quinoline, isoquinoline, phthalazine, and benzothiazole reacted with γ-lactams/amides to give the corresponding C(sp2)-H amidoalkylation products in moderate to good yields with high regioselectivity. This visible-light-induced photocatalyst-free reaction was conducted in H2O at ambient temperature, which comply with the principles of "green chemistry". The new K2S2O8 catalytic mechanism was investigated with control experiments.
- Chen, Zhi,Li, Jianjun,Ren, Quanlei,Song, Shengjie,Wang, Chaodong,Xu, Ning,Zhou, Jiadi
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supporting information
p. 5753 - 5758
(2021/08/23)
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- Direct functionalization of quinoxalin-2(1H)-one with alkanes: C(sp2)-H/C(sp3)-H cross coupling in transition metal-free mode
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Considering the significance of pharmaceutically important heterocycles, efficient and highly versatile protocols for the functionalization of diverse heterocycles with easily accessible feedstock are crucial. Here, we have reported selective alkylation of quinoxalin-2(1H)-one with a broad class of hydrocarbons having different C(sp3)-H bonds with varying bond strengths using di-tert-butyl peroxide (DTBP) as an alkoxyl radical mediator for hydrogen atom transfer (HAT). This dehydrogenative coupling approach utilizes feedstock chemicals such as cycloalkanes, cyclic ethers and alkyl arenes as coupling partners. This protocol exhibits good functional group compatibility and selectivity regarding both heterocycles and unactivated alkanes. Moreover, this methodology allows functionalization of relatively strong C-H bonds of adamantane and exclusive selectivity towards 3° C(sp3)-H bonds is observed. We also illustrate the applicability of this C(sp2)-H/C(sp3)-H cross-coupling for practical access to bioactive pharmaceuticals.
- Dagar, Neha,Raha Roy, Sudipta,Singh, Swati
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p. 5383 - 5394
(2021/06/28)
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- Direct photoexcitation of benzothiazolines: Acyl radical generation and application to access heterocycles
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An acyl radical generation and functionalization strategy through direct photoexcitation of benzothiazolines has been developed. The formed acyl radical species can either be trapped by quinoxalin-2-ones to realize their C(3)-H functionalization or trigger a cascade radical cyclization with isonitriles to synthesise biologically important phenanthridines. The synthetic value of this protocol can be further illustrated by the modification of quinoxalin-2-ones, containing important natural products and drug-based complex molecules.
- He, Xiang-Kui,Li, Lei,Lu, Juan,Xuan, Jun,Ye, Hai-Bing
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- Light-driven selective aerobic oxidation of (iso)quinoliniums and related heterocycles
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Selective C1-H/C4-H carbonylation of N-methylene iminium salts, catalyzed by visible-light photoredox and oxygen in the air, has been reported. A ruthenium complex acts as a chemical switch to conduct two different reaction pathways and to afford two diff
- Zhou, Meimei,Yu, Keyang,Liu, Jianxin,Shi, Weimei,Pan, Yingming,Tang, Haitao,Peng, Xiangjun,Liu, Qian,Wang, Hengshan
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p. 16246 - 16251
(2021/05/19)
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- Rapid alkenylation of quinoxalin-2(1H)-ones enabled by the sequential Mannich-type reaction and solar photocatalysis
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Herein, a rapid alkenylation of quinoxalin-2(1H)-ones enabled by a combination of Mannich-type reaction and solar photocatalysis is demonstrated. A wide range of functional groups are compatible, affording the corresponding products in moderate-to-good yields. Control experiments illustrate that the in situ generated 1O2 plays a central role in this reaction. This green and efficient strategy provides a practical solution for the synthesis of potentially bioactive compounds that containing a 3,4-dihydroquinoxalin-2(1H)-one structure.
- Huang, Lin,Xu, Jun,He, Lei,Liang, Chenfeng,Ouyang, Yani,Yu, Yongping,Li, Wanmei,Zhang, Pengfei
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p. 3627 - 3631
(2021/05/03)
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- Electro-oxidative C-H azolation of quinoxalin-2(1H)-ones
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We have developed a practical, general protocol for direct C-H azolation reactions of quinoxalin-2(1H)-ones by electro-oxidative cross-coupling. These mild reactions proceed under metal-, oxidant-, and reagent-free conditions to provide synthetically useful azolated quinoxalin-2(1H)-ones. Furthermore, the reactions can be carried out with a pencil lead as an electrode and a 3 V battery as a power source, revealing the remarkable flexibility of this protocol.
- Ding, Ling,Hao, Yanke,Liu, Yuxiu,Niu, Kaikai,Song, Hongjian,Wang, Qingmin,Zhou, Pan
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p. 3246 - 3249
(2021/05/21)
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- Electrochemical decarboxylative C3 alkylation of quinoxalin-2(1: H)-ones with N -hydroxyphthalimide esters
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We have developed a protocol for electrochemical decarboxylative C3 alkylation of a wide range of quinoxalin-2(1H)-ones under metal- and additive-free conditions. N-Hydroxyphthalimide esters derived from chain, cyclic, primary, secondary, and tertiary carboxylic acids with a broad scope proved to be suitable substrates. This operationally simple protocol performed in an undivided cell under constant-current conditions is suitable for late-stage functionalization of quinoxalin-2(1H)-ones. The reactions can even be carried out with a 3 V battery as a power source, which demonstrates that organic electrosynthesis can be accomplished without the need for specialized equipment.
- Niu, Kaikai,Song, Lingyun,Hao, Yanke,Liu, Yuxiu,Wang, Qingmin
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supporting information
p. 11673 - 11676
(2020/10/20)
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- Palladium-catalyzed direct Hiyama arylation of quinoxalin-2(1H)-ones with aryl siloxanes in water
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An efficient method for palladium-catalyzed direct Hiyama coupling of various quinoxalin-2(1H)-ones with aryl siloxanes has been developed. The protocol provides a convenient access to a variety of useful C3-arylated 1-methylquinoxalin-2(1H)-one derivatives in reasonable yields by using low cost water as a solvent and oxygen as an oxidant.
- Liu, Xinya,Liu, Zhenwei,Xue, Yingying,Li, Jingya,Zou, Dapeng,Wu, Yangjie,Wu, Yusheng
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- Metal-free C3-H acylation of quinoxalin-2(1: H)-ones with α-oxo-carboxylic acids
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Direct C3-H acylation of quinoxalin-2(1H)-ones with α-oxocarboxylic acids under thermo conditions promoted by PIDA has been achieved in a moderate to good yield in a very fast manner. Mechanistic study revealed that the reaction proceeds via a radical pro
- Li, Yu,Ni, Hangcheng,Shi, Xingzi,Zhang, Xiaoning,Zhao, Fei,Zhao, Jingwei
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supporting information
p. 6558 - 6563
(2020/09/04)
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- Visible-light induced phosphonation of quinoxalines and quinoxalin-2(1H)-ones under aerobic metal-free conditions
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Phosphonation of quinoxalines and quinoxalin-2(1H)-ones utilizing aerobic oxygen as green oxidant under visible light conditions at room temperature has been described. Both quinoxalines and quinoxalin-2(1H)-ones are compatible with alkyl or aryl phosphonates and provided good yields of products through regioselective C-P bond formation under base/ligand-free conditions. Competitive experiments showed quinoxalin-2(1H)-ones are more reactive than quinoxalines under the present conditions, and the control experiments revealed the present transformation proceeds through a radical mechanism.
- Kumar, Rahul,Rawat, Deepa,Subbarayappa, Adimurthy
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p. 6170 - 6175
(2020/10/18)
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- Construction of C(sp2)?C(sp3) Bond between Quinoxalin-2(1H)-ones and N-Hydroxyphthalimide Esters via Photocatalytic Decarboxylative Coupling
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A novel visible-light-driven decarboxylative coupling of alkyl N-hydroxyphthalimide esters (NHP esters) with quinoxalin-2(1H)-ones has been developed. This C(sp2)?C(sp3) bond-forming transformation exhibits excellent substrate generality with respect to both the coupling partners. Of note, a series of 3-primary alkyl-substituted quinoxalin-2(1H)-ones that were difficult to synthesize by previous methods could be obtained in moderate to excellent yields. Additionally, the mild conditions, easy availability of substrates, wide functional group tolerance and operational simplicity make this protocol practical in the synthesis of 3-alkylated quinoxalin-2(1H)-ones.
- Yan, Zhiyang,Sun, Bin,Zhang, Xun,Zhuang, Xiaohui,Yang, Jin,Su, Weike,Jin, Can
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p. 3344 - 3349
(2019/09/06)
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- Nickel-catalyzed electrochemical reductive decarboxylative coupling of: N -hydroxyphthalimide esters with quinoxalinones
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Herein the first example of electrochemically enabled, NiCl2-catalyzed reductive decarboxylative coupling of N-hydroxyphthalimide (NHP) esters with quinoxalinones is reported. A range of primary, secondary, tertiary aliphatic carboxylic acids and amino acid-derived esters were tolerated well. This decarboxylative coupling allows access to structurally diverse 3-alkylated quinoxalinones in up to 91% yields.
- Lian, Fei,Xu, Kun,Meng, Wei,Zhang, Haonan,Tan, Zhoumei,Zeng, Chengchu
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supporting information
p. 14685 - 14688
(2019/12/11)
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- Electrochemical Cross-Coupling of C(sp2)?H with Aryldiazonium Salts via a Paired Electrolysis: an Alternative to Visible Light Photoredox-Based Approach
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Photoredox-based C?H bond functionalization constitutes one of the most powerful and atom-economical approaches to organic syntheses. During this type of reaction, single electron transfer takes place between the photocatalyst (PC) and redox- active substrates. Electrosynthesis also involves electron transfer between substrates and electrodes. In this paper, we focus upon electrochemical cross-coupling of C(sp2)?H with aryldiazonium salts and have developed an efficient electrochemical approach to the Minisci-type arylation reaction. The constant current paired electrosynthesis proceeds in a simple undivided cell without external supporting electrolyte, features a wide range of substrates and is easy to scale-up. These results demonstrate that photoredox-based cross-coupling of C(sp2)?H with aryldiazonium salts can also proceed successfully under paired electrolysis conditions, thereby contributing to understanding of the parallels between photosynthesis and electrosynthesis. (Figure presented.).
- Jiang, Yang-ye,Dou, Gui-yuan,Zhang, Luo-sha,Xu, Kun,Little, R. Daniel,Zeng, Cheng-chu
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p. 5170 - 5175
(2019/11/13)
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- Persulfate-promoted oxidative C-N bond coupling of quinoxalinones and: NH -sulfoximines
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The persulfate-meditated oxidative C-N bond coupling of the C-H bond of quinoxalinones and the N-H bond of NH-sulfoximines is reported. The reaction proceeds smoothly under transition metal-free conditions and provides good to excellent yields of sulfoximidoyl-functionalized quinoxalinone products under mild conditions. The optimized conditions were found to be suitable for a range of sulfoximine and quinoxalinone substrates. This reaction offers a new and convenient strategy to directly install the sulfoximine moiety into the C3 position of quinoxalinone.
- Sumunnee, Ladawan,Pimpasri, Chaleena,Noikham, Medena,Yotphan, Sirilata
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supporting information
p. 2697 - 2704
(2018/04/27)
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- Iodine-Catalyzed Oxidative Cross-Dehydrogenative Coupling of Quinoxalinones and Indoles: Synthesis of 3-(Indol-2-yl)quinoxalin-2-one under Mild and Ambient Conditions
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A highly efficient iodine-catalyzed oxidative cross-dehydrogenative coupling reaction of quinoxalinones and indoles has been developed. Without the requirement of peroxide and acid, this reaction utilizes a catalytic amount of molecular iodine to facilitate the C-C bond formation under ambient air. This simple and easy-to-handle protocol represents an interesting synthetic alternative with a good scope and functional group compatibility.
- Noikham, Medena,Kittikool, Tanakorn,Yotphan, Sirilata
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p. 2337 - 2346
(2018/04/16)
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- Preparation method of quinoxalin-2-one derivative and product purification method
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The invention discloses a preparation method of a quinoxalin-2-one derivative and a product purification method. The preparation method comprises the following steps: using N-methyl-N-phenyltrifluoropropionamide or its derivative as a substrate, adding tert-butyl nitrite into the substrate, using an acetonitrile solution as a solvent, and heating to carry out a reaction in the environment of a buffer solution prepared from a 4 Angstrom molecular sieve, cesium carbonate and acetic acid so as to prepare a crude product. Then, the crude product undergoes purification. The purification method comprises the following steps: filtering the crude product and removing acid to obtain residue; carrying out silica-gel column chromatography on the residue, leaching with an eluate and collecting an eluant; merging product-containing eluants; condensing the merged eluant to remove the solvent; and finally carrying out vacuum drying to obtain a target product. The invention has advantages of simple technological process, low cost and high yield.
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Paragraph 0062; 0063
(2016/10/10)
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- Palladium(II)-catalyzed oxidative arylation of quinoxalin-2(1 H)-ones with arylboronic acids
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A straightforward palladium-catalyzed oxidative C-3 arylation of quinoxalin-2(1H)-ones with arylboronic acids is reported. This protocol is compatible with a wide range of functional groups and allows construction of various biologically important quinoxalin-2(1H)-one backbones.
- Carrer, Amandine,Brion, Jean-Daniel,Messaoudi, Samir,Alami, Mouad
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p. 5606 - 5609
(2013/11/19)
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- Preparation of N-alkyl 2-pyridones via a lithium iodide promoted oto N-alkyl migration: Scope and mechanism
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An efficient and inexpensive LiI-promoted O- to N-alkyl migration of 2-benzyloxy-, 2-allyloxy-, and 2-propargyloxypyridines and heterocycles is reported. The reaction produces the corresponding N-alkyl 2-pyridones and analogues under green, solvent-free conditions in good to excellent yields (30 examples, 20-97% yield). This method has been shown to be intermolecular and requires heat and lithium cation to occur.
- Tasker, Sarah Z.,Bosscher, Michael A.,Shandro, Christina A.,Ryu, Keun Ah,Snapper, Gregory S.,Utter, Jarrad M.,Anderson, Carolyn E.,Lanni, Erica L.,Ellsworth, Bruce A.
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p. 8220 - 8230,11
(2020/10/15)
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- Copper-catalyzed cascade syntheses of 2 H -benzo[ b ][1,4]thiazin-3(4 H)-ones and quinoxalin-2(1 H)-ones through capturing S and N atom respectively from AcSH and TsNH2
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A copper-catalyzed cascade method has been developed to synthesize the 2H-benzo[b][1,4]thiazin-3(4H)-ones from 2-halo-N-(2-halophenyl)-acetamides 1 and AcSH via the SN2/deacetylation/coupling process, and to synthesize the quinoxalin-2(1H)-ones from 1 and TsNH2 via the S N2/coupling/desulfonation process. The target products were obtained with diversity at three positions on their scaffolds.
- Chen, Dingben,Wang, Zhi-Jing,Bao, Weiliang
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supporting information; experimental part
p. 5768 - 5771
(2010/10/03)
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- An efficient domino synthesis of quinoxalin-2(1H)-ones via an S NAr/coupling/demesylation reaction catalyzed by copper(I) as key step
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An efficient copper-catalyzed method for the synthesis of quinoxalin-2(1H)-ones derivatives via domino SNAr/coupling/ demesylation reaction of N-(2-halophenyl)methylsulfonamides with 2-halo amides has been developed. Various quinoxalinones with
- Chen, Dingben,Bao, Weiliang
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supporting information; experimental part
p. 955 - 960
(2010/06/15)
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- Synthesis of substituted N-benzyl pyridones via an O- To N-alkyl migration
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(Chemical Equation Presented) A new LiI-promoted O- to N-alkyl migration has been developed for the conversion of O-alkylated 2-hydroxy pyridines, quinolines, and pyrimidines to the corresponding N-alkylated heterocycles in good to excellent yields (57-99%). This method serves as an efficient means for the preparation of N-benzyl pyridones, quinolones, and pyrimidones.
- Lanni, Erica L.,Bosscher, Michael A.,Ooms, Bartel D.,Shandro, Christina A.,Ellsworth, Bruce A.,Anderson, Carolyn E.
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p. 6425 - 6428
(2008/12/21)
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