- Selective Cleavage and Tunable Functionalization of the C-C/C-N Bonds of N-Arylpiperidines Promoted by tBuONO
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In this paper, selective cleavage and tunable functionalization of the inert C-C/C-N bonds in N-arylpiperidines promoted by tBuONO under metal-free conditions is presented. To be specific, when the reaction was run in acetonitrile in the presence of molecular sieves, the synthetically useful acyclic N-formyl nitriles are formed. On the other hand, when alcohol was used as the reaction medium, the corresponding reactions afforded N-nitroso chain esters as dominating products via a mechanistically different pathway.
- He, Yan,Zheng, Zhi,Liu, Yajie,Qiao, Jiajie,Zhang, Xinying,Fan, Xuesen
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- Phenyl 4-(2-oxopyrrolidin-1-yl)benzenesulfonates and phenyl 4-(2-oxopyrrolidin-1-yl)benzenesulfonamides as new antimicrotubule agents targeting the colchicine-binding site
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We recently designed and prepared new families of potent antimicrotubule agents designated as N-phenyl 4-(2-oxoimidazolidin-1-yl)benzenesulfonates (PIB–SOs) and phenyl 4-(2-oxoimidazolidin-1-yl)benzenesulfonamides (PIB–SAs). Our previous structure-activity relationship studies (SAR) focused on the aromatic ring B of PIB-SOs and PIB-SAs leaving the impact of the phenylimidazolidin-2-one moiety (ring A) on the binding to the colchicine-binding site (C-BS) poorly studied. Therefore, the aim of the present study was to evaluate the effect of replacing the imidazolidin-2-one (IMZ) group by a pyrrolidin-2-one moiety. To that end, 15 new phenyl 4-(2-oxopyrrolidin-1-yl)benzenesulfonate (PYB–SO) and 15 phenyl 4-(2-oxopyrrolidin-1-yl)benzenesulfonamide (PYB-SA) derivatives were designed, prepared, chemically characterised and biologically evaluated. PYB-SOs and PYB-SAs exhibit antiproliferative activity in the low nanomolar to low micromolar range (0.0087–8.6 μM and 0.056–21 μM, respectively) on human HT-1080, HT-29, M21 and MCF7 cancer cell lines. Moreover, they block cell cycle progression in G2/M phase. Immunofluorescence, tubulin affinity and tubulin polymerisation assays show that they cause microtubule depolymerisation by docking the C-BS. In addition, docking assays with the most potent derivatives show binding affinity toward the C-BS and they also exhibit weak or no toxicity toward chick embryos. Finally, physicochemical properties calculated using the SwissADME algorithm show that PYB-SOs and PYB-SAs are promising new families of antimicrotubule agents.
- Gagné-Boulet, Mathieu,Bouzriba, Chahrazed,Chavez Alvarez, Atziri Corin,Fortin, Sébastien
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- Electroselective and Controlled Reduction of Cyclic Imides to Hydroxylactams and Lactams
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An efficient and practical electrochemical method for selective reduction of cyclic imides has been developed using a simple undivided cell with carbon electrodes at room temperature. The reaction provides a useful strategy for the rapid synthesis of hydroxylactams and lactams in a controllable manner, which is tuned by electric current and reaction time, and exhibits broad substrate scope and high functional group tolerance even to reduction-sensitive moieties. Initial mechanistic studies suggest that the approach heavily relies on the utilization of amines (e.g., i-Pr2NH), which are able to generate α-aminoalkyl radicals. This protocol provides an efficient route for the cleavage of C-O bonds under mild conditions with high chemoselectivity.
- Bai, Ya,Shi, Lingling,Zheng, Lianyou,Ning, Shulin,Che, Xin,Zhang, Zhuoqi,Xiang, Jinbao
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supporting information
p. 2298 - 2302
(2021/04/05)
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- Minimization of Back-Electron Transfer Enables the Elusive sp3 C?H Functionalization of Secondary Anilines
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Anilines are some of the most used class of substrates for application in photoinduced electron transfer. N,N-Dialkyl-derivatives enable radical generation α to the N-atom by oxidation followed by deprotonation. This approach is however elusive to monosubstituted anilines owing to fast back-electron transfer (BET). Here we demonstrate that BET can be minimised by using photoredox catalysis in the presence of an exogenous alkylamine. This approach synergistically aids aniline SET oxidation and then accelerates the following deprotonation. In this way, the generation of α-anilinoalkyl radicals is now possible and these species can be used in a general sense to achieve divergent sp3 C?H functionalization.
- Zhao, Huaibo,Leonori, Daniele
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supporting information
p. 7669 - 7674
(2021/03/08)
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- A ligand-free copper-catalyzed strategy to the N-arylation of indazole using aryl bromides
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A simple and efficient strategy for the C–N cross-coupling of indazole with a variety of substituted aryl bromides is reported. Under the optimized conditions, a broad scope of N-arylated products were obtained in good to excellent yields (up to 87%) under the ligand-free conditions.
- Bai, Di-Xiang,Lim, Rachel Sin-Ee,Ng, Hui-Fen,Teo, Yong-Chua
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supporting information
p. 1398 - 1405
(2021/03/08)
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- Synthesis of Aliphatic Amides through a Photoredox Catalyzed Radical Carbonylation Involving Organosilicates as Alkyl Radical Precursors
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Alkyl radicals, from primary to tertiary, formed by photocatalyzed oxidation of organosilicates, are involved efficiently in radical carbonylation with carbon monoxide (CO), in the presence of various amines and CCl4, leading to a variety of amides in moderate to good yields. (Figure presented.).
- Cartier, Alex,Levernier, Etienne,Dhimane, Anne-Lise,Fukuyama, Takahide,Ollivier, Cyril,Ryu, Ilhyong,Fensterbank, Louis
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p. 2254 - 2259
(2020/05/06)
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- Air- And moisture-stable Xantphos-ligated palladium dialkyl complex as a precatalyst for cross-coupling reactions
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Although xantphos has been employed in a variety of palladium-catalyzed cross-coupling reactions, there has been little progress in developing Xantphos-ligated precatalysts. In this report, we describe a Xantphos-ligated palladium dialkyl complex that acts as a powerful precatalyst for C-N, C-S, and C-C cross-coupling reactions. This precatalyst is air- and moisture stable but can be thermally activated in the absence of external reagents. Additionally, potential catalyst inhibitors are not generated during the precatalyst activation. This complex thus represents a convenient alternative to previously reported classes of Xantphos-ligated precatalysts.
- Takahashi, Rina,Kubota, Koji,Ito, Hajime
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supporting information
p. 407 - 410
(2020/01/13)
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- Highly-chemoselective step-down reduction of carboxylic acids to aromatic hydrocarbons: Via palladium catalysis
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Aryl carboxylic acids are among the most abundant substrates in chemical synthesis and represent a perfect example of a traceless directing group that is central to many processes in the preparation of pharmaceuticals, natural products and polymers. Herein, we describe a highly selective method for the direct step-down reduction of carboxylic acids to arenes, proceeding via well-defined Pd(0)/(ii) catalytic cycle. The method shows a remarkably broad substrate scope, enabling to direct the classical acyl reduction towards selective decarbonylation by a redox-neutral mechanism. The utility of this reaction is highlighted in the direct defunctionalization of pharmaceuticals and natural products, and further emphasized in a range of traceless processes using removable carboxylic acids under mild, redox-neutral conditions orthogonal to protodecarboxylation. Extensive DFT computations were conducted to demonstrate preferred selectivity for the reversible oxidative addition and indicated that a versatile hydrogen atom transfer (HAT) pathway is operable.
- Liu, Chengwei,Qin, Zhi-Xin,Ji, Chong-Lei,Hong, Xin,Szostak, Michal
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p. 5736 - 5742
(2019/06/18)
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- Single-Electron-Transfer-Induced C(sp3)-N Couplings via C-C Bond Cleavage of Cycloketoxime Esters
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A practical single-electron-transfer-induced selective C(sp3)-N coupling of cycloketoximes with anilines via C-C bond cleavage under copper-catalytic and synergetic photoredox/copper-catalytic reaction systems has been uncovered. These two powerful and simple protocols demonstrated excellent selectivity and good functional group compatibility without any base or ligand control. Preliminary mechanistic experiments indicated that a radical-mediated process was involved in these transformations.
- Shi, Zhuangzhi,Wang, Minyan,Zhao, Binlin
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- Ruthenium-catalyzed synthesis of: N -substituted lactams by acceptorless dehydrogenative coupling of diols with primary amines
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Herein, we report the first example of synthesis of N-substituted lactams via an acceptorless dehydrogenative coupling of diols with primary amines in one step, which was enabled by combining Ru3(CO)12 with a hybrid N-heterocyclic carbene-phosphine-phosphine ligand as the catalyst.
- Zheng, Yanling,Nie, Xufeng,Long, Yang,Ji, Li,Fu, Haiyan,Zheng, Xueli,Chen, Hua,Li, Ruixiang
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supporting information
p. 12384 - 12387
(2019/10/19)
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- Catalyst-Free Reductive Coupling of Aromatic and Aliphatic Nitro Compounds with Organohalides
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A rare reductive coupling of nitro compounds with organohalides has been realized. The reaction is initiated by a partial reduction of the nitro group to a nitrenoid intermediate. Therefore, not only aromatic but also aliphatic nitro compounds are efficiently transformed into monoalkylated amines, with organohalides as the alkylating agent. Given the innate reactivity of the nitrenoid, a catalyst is not required, resulting in a high tolerance for aryl halide substituents in both starting materials.
- Rauser, Marian,Eckert, Raphael,Gerbershagen, Max,Niggemann, Meike
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supporting information
p. 6713 - 6717
(2019/04/14)
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- Selective synthesis of pyrrolidin-2-ones and 3-iodopyrroles: Via the ring contraction and deformylative functionalization of piperidine derivatives
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In this paper, a selective synthesis of pyrrolidin-2-ones and 3-iodopyrroles via the cascade reactions of N-substituted piperidines is presented. Mechanistically, the formation of pyrrolidin-2-ones involves a domino process including the in situ formation of pyrrolidine-2-carbaldehyde followed by carboxylic acid formation, decarboxylation and ipso-oxidation. On the other hand, 3-iodopyrroles are believed to be formed via the initial generation of pyrrolidine-2-carbaldehyde followed by carboxylic acid formation, decarboxylation, dehydrogenation, iodination and aromatization. Interestingly, either pyrrolidin-2-ones or 3-iodopyrroles could be obtained selectively from the same substrates, and the selectivity was easily tuned by using a specific oxidant and additive.
- Wang, Fang,Zhang, Xinying,He, Yan,Fan, Xuesen
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p. 156 - 164
(2019/01/08)
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- Pyrrolidone compound synthesis method
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The invention discloses a pyrrolidone compound synthesis method, and belongs to the technical field of organic synthesis. Saturated cyclic tertiary amine 1 is added into solvents, and heating reactionis performed in the presence of oxidizing agent, cupric salt, potassium hydrogen persulfate compound salt (Oxone) and oxygen mixture, additives, elementary iodine or iodated metal salt and the like to obtain pyrrolidone 2. According to the method, a pyrrolidone compound is synthesized by cascade reaction of oxidization retraction, decarbonylation and in-situ oxidization of saturated cyclic tertiary amine compounds, the method has the advantages of simplicity and convenience in operation, mild conditions, wide substrate application range and the like, and an economical, practical, green and environment-friendly novel method is provided for synthesis of the pyrrolidone compound.
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Paragraph 0014-0016; 0017-0018; 0019-0020; 0021-0044
(2019/03/08)
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- Method for catalytically oxidizing amine to be synthesized into amide through dipyridyl-type manganese catalyst
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The invention discloses a methodfor catalytically oxidizing amine to be synthesized into amide througha dipyridyl-type manganese catalyst. According to the method, a dipyridyl manganese complex formedafter coordination of a dipyridyl-type complex and cheap metal manganese serves as the catalyst, clean and environment-friendly hydrogen peroxide serves as an oxidizing agent, oxidation of N ortho-position sp3 C-H bonds catalyzed by the cheap metal manganese is achieved, and the amine is directly oxidized to obtain the amide. Compared with existing methods, the method has the advantages that theadopted catalyst is low in price, the preparing method is simple, raw materials are easy to obtain, the use level of the catalyst is low, the substrate range is wide, the reaction condition is mild, the operation is simple and environmentally friendly, the reaction time is short, the yield is high, the selectivity is high, and the industrialization cost is low.
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Paragraph 0017-0027; 0046-0048
(2019/06/30)
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- C?N Cross-Coupling Reactions Under Mild Conditions Using Singlet Di-Radical Nickel(II)-Complexes as Catalyst: N-Arylation and Quinazoline Synthesis
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Herein we report a cost-effective synthetic approach for C?N cross-coupling reactions of a broad array of nitrogen nucleophiles and aryl halides under mild conditions. These reactions are catalyzed by an inexpensive, air-stable, earth-abundant and easy-to-prepare singlet di-radical nickel(II)-catalyst containing two antiferromagnetically coupled single-electron oxidized diiminosemiquinonato type ligands. This protocol provides an alternative method for C?N cross-coupling reactions avoiding nickel(0)/nickel(II) or nickel(I)/nickel(III) redox processes via cooperative participation of metal and ligand-centered redox events. Besides a wide range of N-arylation reactions, by judicious choice of aryl halides and nitrogen nucleophiles the synthesis of a variety of polysubstituted quinazolines has been achieved in moderate to good yields under relatively mild reaction conditions. Our catalyst has been found to be almost equally effective in quinazoline synthesis via C?N cross-coupling of (i) 2-bromobenzylamine with benzamide, and (ii) 2-bromobenzylbromide with amidine. Control experiments and DFT studies were performed to improve the understanding of the cooperative participation of ligand and metal (nickel)-centered redox events during oxidative addition/reductive elimination processes of the catalytic cycle and to shed light on the plausible mechanistic pathway of the C?N cross-coupling reactions. (Figure presented.).
- Sikari, Rina,Sinha, Suman,Chakraborty, Gargi,Das, Siuli,van Leest, Nicolaas Petrus,Paul, Nanda D.
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supporting information
p. 4342 - 4353
(2019/08/21)
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- Iron-Catalyzed/Mediated C-N Bond Formation: Competition between Substrate Amination and Ligand Amination
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Iron catalyzed carbon-nitrogen bond formation reactions of a wide variety of nucleophiles and aryl halides using well-defined iron-complexes featuring redox noninnocent 2-(arylazo)-1,10-phenanthroline (L1) ligands are reported. Besides substrate centered C-N coupling, C-N bond formation reactions were also observed at the ortho- and para-positions of the phenyl ring of the coordinated azo-aromatic scaffolds affording new tetradentate ligands, 2-N-aryl-(2-arylazo)-1,10-phenanthroline (L2), and tridentate ligands, 4-N-aryl-(2-arylazo)-1,10-phenanthroline (L3), respectively. Control experiments and mechanistic studies reveal that the complex [FeL1Cl2] (1) undergoes in situ reduction during the catalytic reaction to produce the monoanionic complex [1]-, which then acts as the active catalyst. The metal (iron) and the coordinated ligand were found to work in a cooperative manner during the transfer processes involved in the fundamental steps of the catalytic cycle. Detailed experimental and theoretical (DFT) studies were performed to get insight into the competitive substrate versus ligand centered amination reactions.
- Sinha, Suman,Sikari, Rina,Sinha, Vivek,Jash, Upasona,Das, Siuli,Brand?o, Paula,Demeshko, Serhiy,Meyer, Franc,De Bruin, Bas,Paul, Nanda D.
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p. 1935 - 1948
(2019/01/25)
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- Diversity-Oriented Synthesis of Heterocycles: Al(OTf)3-Promoted Cascade Cyclization and Ionic Hydrogenation
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An efficient and facile method has been developed for the diversity-oriented synthesis of heterocycles. Hexahydrophenoxazines, tetrahydroquinolines, indolines, hexahydrocarbazoles, and lactones were conducted via Al(OTf)3-promoted cascade cyclization and ionic hydrogenation. Furthermore, this protocol was utilized to smoothly prepare piracetam and its key intermediate as well.
- Liu, Tianqi,Jia, Wenqiang,Xi, Qiumu,Chen, Yonghui,Wang, Xiaojian,Yin, Dali
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p. 1387 - 1393
(2018/02/10)
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- Copper(I)-USY as a Ligand-Free and Recyclable Catalyst for Ullmann-Type O-, N-, S-, and C-Arylation Reactions: Scope and Application to Total Synthesis
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The copper(I)-doped zeolite CuI-USY proved to be a versatile, efficient, and recyclable catalyst for various Ullmann-type coupling reactions. Easy to prepare and cheap, this catalytic material enables the arylation and heteroarylation of diverse O-, N-, S-, and C-nucleophiles under ligand-free conditions while exhibiting large functional group compatibility. The facility of this catalyst to promote C-O bond formation was further demonstrated with the total synthesis of 3-methylobovatol, a naturally occurring diaryl ether of biological relevance. From a mechanistic viewpoint, two competitive pathways depending on the nature of the nucleophile and consistent with the obtained results have been proposed.
- Garnier, Tony,Danel, Mathieu,Magné, Valentin,Pujol, Anthony,Bénéteau, Valérie,Pale, Patrick,Chassaing, Stefan
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p. 6408 - 6422
(2018/05/31)
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- Ruthenium-Pincer-Catalyzed Hydrogenation of Lactams to Amino Alcohols
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By using the commercially available ruthenium pincer complex (Ru-MACHO-BH) as a catalyst, the challenging direct hydrogenation of lactams and analogues has been successfully accomplished to deliver corresponding value-added amino alcohols in good-to-excellent yields under mild reaction conditions. Remarkably, in addition to N-protected lactams, unprotected ones could also be readily reduced in the presence of a catalytic amount of weak base or even under neutral reaction conditions, which further highlights the broad substrate scope and the protocol efficiency.
- Chen, Jiangbo,Wang, Jiaquan,Tu, Tao
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p. 2559 - 2565
(2018/07/30)
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- Acceleration of Pd-Catalyzed Amide N-Arylations Using Cocatalytic Metal Triflates: Substrate Scope and Mechanistic Study
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The Pd/xantphos-catalyzed cross-coupling of amides and aryl halides is accelerated by cocatalytic metal triflate additives. A survey of nitrogen nucleophiles reveals improved yields for a variety of N-aryl amide products when Al(OTf)3 is employed as a catalytic additive, with some exceptions. Initial rates of catalysis indicate that the Lewis acid acceleration is more pronounced when bromobenzene (PhBr) is used in comparison with iodobenzene (PhI). The observation of an aryl halide dependence on rate and various qualitative kinetic experiments are consistent with a mechanism in which ligand exchange of halide for amide ("transmetalation") is turnover limiting. The mechanism may be different depending on whether PhBr or PhI is used as a coupling partner. Oxidative addition complexes (xantphos)Pd(Ph)(X) (X = Br, I; xantphos = 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene), likely intermediates in catalysis, have been prepared; their differing interactions with Yb(OTf)3 in solution resemble the halide dependence of the catalytic mechanism, which we propose originates from a reversible Lewis acid mediated halide abstraction during catalysis.
- Becica, Joseph,Dobereiner, Graham E.
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p. 5862 - 5870
(2017/09/15)
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- Efficient Synthesis of N-Substituted 2,4-Azepandione Ring System as an Active Intermediate for Heterocyclic Syntheses
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An improved efficient synthesis for 2,4-azepandiones (3, 8, and 14) could be achieved by a careful control of the reaction conditions to cyclize ethyl 4-(N-acetylarylamino) butanoate (1, 7, and 13), respectively. The ethyl 4-arylamino butanoate (9 or 12) was prepared by stirring the ethyl 4-bromobutanoate and substituted anilines at room temperature. Then, they were acetylated with acetyl chloride and triethylamine under the conditions that avoid the formation of 2-pyrrolidinone derivatives 10. Due to the rapid decomposition of the acetylated product (7 or 13) to its starting material (9 or 12), the reaction mixture is directly transferred without workup to the next cyclization step. The azepandione synthesis is favored by using a weak base at low temperature, where it is in a competition with the other modes of ring closure. The structures of the new compounds were supported by correct analytical and spectral data.
- Waly, Mohamed A.,Yossif, Shiam A.,Ibrahim, Ismail T.,Sofan, Mamdouh A.
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p. 1318 - 1326
(2017/03/27)
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- Metal-Free Synthesis of N-Aryl Amides using Organocatalytic Ring-Opening Aminolysis of Lactones
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Catalytic ring-opening of bio-sourced non-strained lactones with aromatic amines can offer a straightforward, 100 % atom-economical, and sustainable pathway towards relevant N-aryl amide scaffolds. Herein, the first general, metal-free, and highly efficient N-aryl amide formation is reported from poorly reactive aromatic amines and non-strained lactones under mild operating conditions using an organic bicyclic guanidine catalyst. This protocol has high application potential as exemplified by the formal syntheses of drug-relevant molecules.
- Guo, Wusheng,Gómez, José Enrique,Martínez-Rodríguez, Luis,Bandeira, Nuno A. G.,Bo, Carles,Kleij, Arjan W.
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p. 1969 - 1975
(2017/05/16)
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- Synthesis of N -Aryl and N -Heteroaryl γ-, δ-, and ?-Lactams Using Deprotometalation-Iodination and N -Arylation, and Properties Thereof
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Xanthone, thioxanthone, fluorenone, benzophenone, 2-benzoylpyridine, dibenzofuran, and dibenzothiophene were deprotonated using a base prepared in situ from MCl 2 ·TMEDA (M = Zn or Cd; TMEDA = N, N, N ′, N ′-tetramethylethylenediamine) and lithium 2,2,6,6-tetramethylpiperidide in a 1:3 ratio, as demonstrated by subsequent iodolysis. The different aryl halides were involved as partners in the N -arylation of pyrrolidin-2-one. In the presence of copper(I) iodide and tripotassium phosphate, and using dimethyl sulfoxide as solvent, the reactions could be performed in yields ranging from 40 to 70%. Most of the products were tested for their antimicrobial, antifungal, antioxidant, and cytotoxic (MCF-7) activity.
- Amara, Rim,Bentabed-Ababsa, Ghenia,Hedidi, Madani,Khoury, Joseph,Awad, Ha?an,Nassar, Ekhlass,Roisnel, Thierry,Dorcet, Vincent,Chevallier, Floris,Fajloun, Ziad,Mongin, Florence
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p. 4500 - 4516
(2017/09/26)
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- Discovery of (S)-3′-hydroxyblebbistatin and (S)-3′-aminoblebbistatin: polar myosin II inhibitors with superior research tool properties
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In search of myosin II inhibitors with superior research tool properties, a chemical optimization campaign of the blebbistatin scaffold was conducted in this paper. (S)-Blebbistatin is the best known small-molecule inhibitor of myosin II ATPase activity. Unfortunately, as a research tool this compound has several deficiencies: it is photolabile and (photo)toxic, has low water solubility, and its (fluorescent) precipitates interfere in (fluorescence) readouts. In view of obtaining tool compounds with improved properties, both enantiomers of a series of D-ring modified polar analogs were prepared. We identified (S)-3′-hydroxyblebbistatin (S)-2 and (S)-3′-aminoblebbistatin (S)-3 as two myosin II inhibitors with a 30-fold higher water solubility than (S)-blebbistatin. These molecules furthermore do not cause interference in (fluorescence) readouts. (S)-2 and (S)-3 thus are superior alternatives to (S)-blebbistatin as research tools to study myosin II.
- Verhasselt, Sigrid,Roman, Bart I.,De Wever, Olivier,Van Hecke, Kristof,Van Deun, Rik,Bracke, Marc E.,Stevens, Christian V.
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supporting information
p. 2104 - 2118
(2017/03/11)
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- An Annulative Synthetic Strategy for Building Triphenylene Frameworks by Multiple C?H Bond Activations
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C?H activation is a versatile tool for appending aryl groups to aromatic systems. However, heavy demands on multiple catalytic cycle operations and site-selectivity have limited its use for graphene segment synthesis. A Pd-catal- yzed one-step synthesis of functionalized triphenylene frameworks is disclosed, which proceeds by 2- or 4-fold C?H arylation of unactivated benzene derivatives. A Pd2(dibenzylideneacetone)3 catalytic system, using cyclic diaryliodonium salts as π-extending agents, leads to site-selective inter- and intramolecular tandem arylation sequences. Moreover, N-substituted triphenylenes are applied to a field-effect transistor sensor for rapid, sensitive, and reversible alcohol vapor detection.
- Mathew, Bijoy P.,Yang, Hyun Ji,Kim, Joohee,Lee, Jae Bin,Kim, Yun-Tae,Lee, Sungmin,Lee, Chang Young,Choe, Wonyoung,Myung, Kyungjae,Park, Jang-Ung,Hong, Sung You
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supporting information
p. 5007 - 5011
(2017/04/24)
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- Copper-Mediated C-N Coupling of Arylsilanes with Nitrogen Nucleophiles
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A method for the oxidative coupling of arylsilanes with nitrogen nucleophiles is reported. This method occurs with a broad range of heptamethyltrisiloxylarenes and nitrogen nucleophiles, proceeds with the arylsilane as limiting reagent, and does not require a fluoride activator with electron-poor arylsilanes. The combination of this method with C-H silylation generates arylamines from unactivated arenes with site selectivity controlled by steric effects. This combination of steps gives direct access to many compounds that cannot be accessed via alternative C-H functionalization methods, including direct C-H amination or the combination of C-H borylation and amination.
- Morstein, Johannes,Kalkman, Eric D.,Cheng, Chen,Hartwig, John F.
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supporting information
p. 5244 - 5247
(2016/11/02)
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- Visible-Light Photoredox-Catalyzed Giese Reaction: Decarboxylative Addition of Amino Acid Derived α-Amino Radicals to Electron-Deficient Olefins
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A tin- and halide-free, visible-light photoredox-catalyzed Giese reaction was developed. Primary and secondary α-amino radicals were generated readily from amino acids in the presence of catalytic amounts of an iridium photocatalyst. The reactivity of the α-amino radicals has been evaluated for the functionalization of a variety of activated olefins.
- Millet, Anthony,Lefebvre, Quentin,Rueping, Magnus
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supporting information
p. 13464 - 13468
(2016/09/13)
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- Cyclization of N-arylcyclopropanecarboxamides into N-arylpyrrolidin-2-ones under electron ionization and in the condensed phase
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Rationale: Mass spectrometry is known as an excellent method to predict the behavior of organic compounds in solution. The behavior of organic compounds in the gas phase inside the ion source of a mass spectrometer allows their intrinsic properties to be defined, avoiding the influence of intermolecular interactions, counter ions and solvent effects. Methods: Arylpyrrolidin-2-ones were obtained by condensed-phase synthesis from the corresponding N-arylcyclopropanecarboxamides. Electron ionization (EI) with accurate mass measurements by high-resolution time-of-flight mass-spectrometry and quantum chemical calculations were used to understand the behavior of the molecular radical cations of N-arylcyclopropanecarboxamides and N-arylpyrrolidin-2-ones in the ion source of a mass spectrometer. The geometries of the molecules, transition states, and intermediates were fully optimized using DFT-PBE calculations. Results: Fragmentation schemes, ion structures, and possible mechanisms of primary isomerisation were proposed for isomeric N-arylcyclopropanecarboxamides and N-arylpyrrolidin-2-ones. Based on the fragmentation pattern of the N-arylcyclopropanecarboxamides, isomerisation of the original M+? ions into the M+? ions of the N-arylpyrrolidin-2-ones was shown to be only a minor process. In contrast, this cyclization proceeds easily in the condensed phase in the presence of Br?nsted acids. Conclusions: Based on the experimental data and quantum chemical calculations the principal mechanism of decomposition of the molecular ions of N-arylcyclopropanecarboxamides involves their direct fragmentation without any rearrangements. An alternative mechanism is responsible for the isomerisation of a small portion of the higher energy molecular ions into the corresponding N-arylpyrrolidin-2-one ions. Copyright
- Lebedev, A. T.,Mazur, D. M.,Kudelin, A. I.,Fedotov, A. N.,Gloriozov, I. P.,Ustynyuk, Yu. A.,Artaev, V. B.
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p. 2416 - 2422
(2016/10/22)
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- Green alternative solvents for the copper-catalysed arylation of phenols and amides
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Investigation of the use of green organic solvents for the Cu-catalysed arylation of phenols and amides is reported. Alkyl acetates proved to be efficient solvents in the catalytic processes, and therefore excellent alternatives to the typical non-green solvents used for Cu-catalysed arylation reactions. Solvents such as isosorbide dimethyl ether (DMI) and diethyl carbonate also appear to be viable possibilities for the arylation of phenols. Finally, a novel copper catalysed acyl transfer process is reported.
- Sambiagio, Carlo,Munday, Rachel H.,John Blacker,Marsden, Stephen P.,McGowan, Patrick C.
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p. 70025 - 70032
(2016/08/06)
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- Highly efficient and recyclable copper based ionic liquid catalysts for amide synthesis
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A series of Cu based ionic liquids was synthesized by the reaction of 1-butyl-3-methylimidazolium salts and copper(ii) salts. These ionic liquids were investigated as catalysts in the synthesis of amides (primary, secondary and tertiary amides). For easy separation and recycling, the Cu based ionic liquids were decorated on nanocrystalline silicalite. The materials were characterized using powder X-ray diffraction, nitrogen adsorption, scanning and transmission electron microscopy, thermogravimetric analysis, and nuclear magnetic resonance, Fourier transform infrared and UV-visible spectroscopy. The Cu based ionic liquids decorated on nanocrystalline silicalite were found to be efficient and recyclable catalysts for the amide synthesis. The catalysts were found to be stable and show negligible loss of the activity even after five cycles.
- Rani, Poonam,Srivastava, Rajendra
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p. 7162 - 7170
(2016/08/09)
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- Ullmann reaction through ecocatalysis: Insights from bioresource and synthetic potential
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We report the elaboration of novel bio-sourced ecocatalysts for the Ullmann coupling reaction. Ecocatalysis is based on the recycling of metals issued from phytoremediation or rehabilitation, and an innovative chemical valorization of the subsequent biomass in the field of catalysis. Here, we describe efficient copper accumulation by plants via phytoextraction and rhizofiltration. These phytotechnologies were revisited to demonstrate a novel potential of these natural resources for green chemistry. Taking advantage of the remarkable ability of the selected plants to accumulate Cu(ii) species into their roots or leaves, the latter can be directly used for the preparation of ecocatalysts, called Eco-Cu. The formed Eco-Cu catalysts are thoroughly characterized via ICP-MS, IR studies of pyridine sorption/desorption, TEM, XRD, SM and model reactions, in order to elucidate the chemical composition and catalytic activity of these new materials. Significant differences of properties and activities were observed between Eco-Cu and conventional Cu catalysts. Eco-Cu are highly active catalysts in Ullmann coupling reactions with lower Cu quantities compared to known copper catalysts.
- Clavé, Guillaume,Garel, Claire,Poullain, Cyril,Renard, Brice-Lo?c,Olszewski, Tomasz K.,Lange, Bastien,Shutcha, Mylor,Faucon, Michel-Pierre,Grison, Claude
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p. 59550 - 59564
(2016/07/06)
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- Orthogonal Discrimination among Functional Groups in Ullmann-Type C-O and C-N Couplings
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The copper-catalyzed arylation of nucleophiles has been established as an efficient methodology for the formation of C-C and C-heteroatom bonds. Considering the advances during the last two decades, the ligand choice plays a key role in such transformations and can strongly influence the catalytic efficiency. The applicability of these Ullmann-type coupling reactions regarding the orthogonal selectivity of different functional groups constitutes a challenging subject for current synthetic strategies. Herein, we report a useful toolkit of Cu-based catalysts for the chemoselective arylation of a wide-range of nucleophiles in competitive reactions using aryl iodides and bromides. We show in this work that the arylation of all kinds of amides can be orthogonal to that of amines (aliphatic or aromatic) and phenol derivatives. This high chemoselectivity can be governed by the use of different ligands, yielding the desired coupling products under mild conditions. The selectivity trends are maintained for electronically biased iodobenzene and bromobenzene electrophiles. Radical clock experiments discard the occurrence of radical-based mechanisms.
- Rovira, Mireia,Soler, Marta,Güell, Imma,Wang, Ming-Zheng,Gómez, Laura,Ribas, Xavi
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supporting information
p. 7315 - 7325
(2016/09/09)
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- Selective copper-catalyzed N-arylation of lactams with arylboronic acids under base- and ligand-free conditions
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An oxidative copper-catalyzed cross-coupling of arylboronic acids with various ring-size lactams has been developed. The N-arylated lactams were obtained in moderate to excellent yields without any additional bases, ligands, or additives. This reaction shows complete selectivity for N-arylation of lactams in the presence of a hydroxyl group.
- Bathini, Thulasiram,Rawat, Vikas Singh,Sreedhar, Bojja
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supporting information
p. 1348 - 1351
(2015/06/16)
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- Cycloaddition of Enamine and Iminium Ion Intermediates Formed in the Reaction of N -Arylpyrrolidines with T-HYDRO
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The reaction of N-arylpyrrolidine derivatives with 70% aqueous tert-butyl hydroperoxide (T-HYDRO) in the presence of NaOAc·3H2O gives tetracyclic amines in 59-78% yields via cycloaddition of the corresponding iminium ion and enamine intermediates formed in situ in cyclohexane solvent. The iminium ion intermediate reacts with t-BuOK in methanol to give the corresponding cyclic amides in 85-88% yields or undergoes alkylation to give the corresponding nitromethyl product in 74-79% yields using t-BuOK and nitromethane in methanol.
- Rao, Gunda Ananda,Periasamy, Mariappan
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p. 2231 - 2236
(2015/09/28)
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- Nickel-Copper-Catalyzed C(sp2)- N Cross-Coupling of Cyclic and Bridged Amides: An Access to Cyclic Enamides and Alkenyl Vince Lactams
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An efficient C(sp2)- N cross-coupling of styrenyl and vinyl halides with cyclic and bridged amides catalyzed by nickel acetonylacetonate [Ni(acac)2] and copper(I) iodide (CuI) in the absence of any ligand has been developed. The reaction conditions are optimized to give the maximum yield of products using cesium carbonate (Cs2CO3) (2.0 equiv.) in N-methyl-2-pyrrolidinone (NMP) at 110 C under argon in the presence of Ni(acac)2/CuI (10 mol% each). A series of alkenyl derivatives of Vince lactams (bridged amides) and cyclic amides are obtained by this procedure. Halogen-containing styrenyl bromides also underwent coupling with amides to provide the products. The coupling is highly chemoselective as during the reactions the halogens (Br, Cl, F) on the aromatic ring remained intact and these can be used for further functionalization to make these enamides more useful. Although the (E)-styrenyl halides produced the corresponding (E)-styrenyl enamides, reactions with (Z)-styrenyl halides produced 1,3-di-ynes instead of (Z)-styrenyl enamides. This may be explained by the possibility of E2 type elimination of (Z)-styrenyl halides in the presence of a strong base like cesium carbonate followed by homocoupling. This catalyst system works efficiently for the N-arylation too along with N-styrenylation and vinylation. The bridged as well as cyclic amides successfully coupled with substituted aryl halides to provide the corresponding products. In general, the reactions are clean and high yielding. The operations are very simple and the products are obtained pure by standard column chromatography. The reaction is compatible with variety of amides and alkenyl bromides. The roles of nickel acetonylacetonate and copper(I) iodide in this reaction have been established and a possible reaction pathway has been outlined. The significant feature of this protocol is the alkenylation of Vince lactams via C(sp2)- N cross-coupling, which has not been reported so far and these products may have much potential in the pharmaceutical industry.
- Maity, Pintu,Kundu, Debasish,Ranu, Brindaban C.
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p. 3617 - 3626
(2016/01/25)
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- Mild and Efficient Cobalt-Catalyzed Cross-Coupling of Aliphatic Amides and Aryl Iodides in Water
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A convenient protocol for the C-N cross-coupling of aliphatic amides and iodobenzene is demonstrated using a simple and inexpensive Co(C2O4)·2H2O/N,N′-dimethylethylenediamine (DMEDA) catalytic system in water. Good yields of N-arylated products were isolated (up to 85%) and the protocol has been successfully applied to the synthesis of the anticancer drug, flutamide.
- Tan, Bryan Yong-Hao,Teo, Yong-Chua
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supporting information
p. 1697 - 1701
(2015/07/20)
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- Br?nsted Acid-Catalyzed Intramolecular Nucleophilic Substitution of the Hydroxyl Group in Stereogenic Alcohols with Chirality Transfer
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The hydroxyl group of enantioenriched benzyl, propargyl, allyl, and alkyl alcohols has been intramolecularly displaced by uncharged O-, N-, and S-centered nucleophiles to yield enantioenriched tetrahydrofuran, pyrrolidine, and tetrahydrothiophene derivatives with phosphinic acid catalysis. The five-membered heterocyclic products are generated in good to excellent yields, with high degree of chirality transfer, and water as the only side-product. Racemization experiments show that phosphinic acid does not promote SN1 reactivity. Density functional theory calculations corroborate a reaction pathway where the phosphinic acid operates as a bifunctional catalyst in the intramolecular substitution reaction. In this mechanism, the acidic proton of the phosphinic acid protonates the hydroxyl group, enhancing the leaving group ability. Simultaneously, the oxo group of phosphinic acid operates as a base abstracting the nucleophilic proton and thus enhancing the nucleophilicity. This reaction will open up new atom efficient techniques that enable alcohols to be used as nucleofuges in substitution reactions in the future.
- Bunrit, Anon,Dahlstrand, Christian,Olsson, Sandra K.,Srifa, Pemikar,Huang, Genping,Orthaber, Andreas,Sj?berg, Per J. R.,Biswas, Srijit,Himo, Fahmi,Samec, Joseph S. M.
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supporting information
p. 4646 - 4649
(2015/04/27)
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- A copper-based metal-organic framework as an efficient and reusable heterogeneous catalyst for ullmann and goldberg type C-N coupling reactions
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A highly porous metal-organic framework (Cu-TDPAT), constructed from a paddle-wheel type dinuclear copper cluster and 2,4,6-tris(3,5-dicarboxylphenylamino)-1,3,5-triazine (H6TDPAT), has been tested in Ullmann and Goldberg type C-N coupling reactions of a wide range of primary and secondary amines with halobenzenes, affording the corresponding N-arylation compounds in moderate to excellent yields. The Cu-TDPAT catalyst could be easily separated from the reaction mixtures by simple filtration, and could be reused at least five times without any significant degradation in catalytic activity.
- Long, Wei,Qiu, Wenge,Guo, Chongwei,Li, Chuanqiang,Song, Liyun,Bai, Guangmei,Zhang, Guizhen,He, Hong,Kuznetsov, Maxim L.
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p. 21178 - 21192
(2016/01/25)
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- Selective formation of α,ω-ester amides from the aminocarbonylation of castor oil derived methyl 10-undecenoate and other unsaturated substrates
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The reaction of long chain alkenes with CO and aniline in the presence of palladium complexes of 1,2-bis-(ditertbutylphosphinomethyl)benzene produces amides with high linear selectivity, with much higher rates and catalyst stability when 2-naphthol and sodium or potassium iodide are added. Unsaturated esters including methyl 10-undecenoate from castor oil give α,ω- ester amides, whilst reactions in THF give N-phenylpyrrolidine.
- Jimenez-Rodriguez, Cristina,Nunez-Magro, Angel A.,Seidensticker, Thomas,Eastham, Graham R.,Furst, Marc R. L.,Cole-Hamilton, David J.
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p. 2332 - 2339
(2014/07/22)
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- Nanoparticle mediated organic synthesis (NAMO-synthesis): CuI-NP catalyzed ligand free amidation of aryl halides
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The first CuI-nanoparticle catalyzed ligand free synthesis of N-aryl amides from aryl halides and arylamides/cyclic amides has been developed. This methodology is further extended for the synthesis of nitrogen heterocycles such as benzimidazole, and quinazolinone via intermolecular amidation reaction followed by cyclization. TEM images of the CuI-NP catalyst showed spherical, well-dispersed particles which provide large surface area for reactivity and have good recyclability. This journal is
- Kumar, Atul,Bishnoi, Ajay Kumar
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p. 41631 - 41635
(2015/05/20)
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- Copper-catalyzed arylation of nitrogen heterocycles from anilines under ligand-free conditions
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The arylation of pyrazole and derivatives can be achieved by coupling arenediazonium species (formed in situ from anilines) by using a catalytic system that employs low-toxicity and inexpensive copper metal under very mild and ligand-free conditions (T = 20 ° C). From other nitrogen heterocycles, the presence of an additive (NBu4I) significantly improves the efficiency of the catalytic system. These results represent the first examples of C-N bond formation from arenediazonium species.
- Toummini, Dounia,Tlili, Anis,Bergs, Julien,Ouazzani, Fouad,Taillefer, Marc
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supporting information
p. 14619 - 14623
(2015/01/09)
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- Synthesis of nitrogen heterocycles via α-aminoalkyl radicals generated from α-silyl secondary amines under visible light irradiation
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We have succeeded in the visible light-mediated synthetic use of α-aminoalkyl radicals derived from α-silyl secondary amines toward addition to α,β-unsaturated carbonyl compounds. The resulting γ-aminocarbonyl compounds are converted into γ-lactams and pyrroles in a one-pot process. This journal is the Partner Organisations 2014.
- Nakajima, Kazunari,Kitagawa, Mai,Ashida, Yuya,Miyake, Yoshihiro,Nishibayashi, Yoshiaki
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supporting information
p. 8900 - 8903
(2014/08/05)
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- CATALYSTS AND PROCESSES FOR THE HYDROGENATION OF AMIDES
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There is provided a process for the reduction of one or more amide moieties in a compound comprising contacting the compound with hydrogen gas and a transition metal catalyst in the presence or absence of a base under conditions for the reduction an amide bond. The presently described processes can be performed at low catalyst loading using relatively mild temperature and pressures, and optionally, in the presence or absence of a base or high catalyst loadings using low temperatures and pressures and high loadings of base to effect dynamic kinetic resolution of achiral amides.
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Paragraph 0183; 0184
(2014/06/24)
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- Ligand-free Ullmann-type C-heteroatom couplings under practical conditions
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A new practical ligand-free protocol for copper-catalyzed C-heteroatom cross-coupling reactions (Ullmann-type) is described. The use of dimethyl sulfoxide (DMSO) as the solvent overcomes the need to use organic auxiliary ligands; thus, DMSO is revealed as a nontoxic and superior solvent for Ullmann-type coupling reactions. This method allows the arylation of a wide range of amides, alcohols, and amines under practical conditions with bromobenzene and iodobenzene derivatives and will likely find direct application in current organic synthesis. The competitive reactivity among different functional groups is reported and rationalized, and the possibility to achieve selective arylation reactions is demonstrated. Copyright
- Gueell, Imma,Ribas, Xavi
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p. 3188 - 3195
(2014/06/09)
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- Nanoparticle mediated organic synthesis (NAMO-synthesis): CuI-NP catalyzed ligand free amidation of aryl halides
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The first CuI-nanoparticle catalyzed ligand free synthesis of N-aryl amides from aryl halides and arylamides/cyclic amides has been developed. This methodology is further extended for the synthesis of nitrogen heterocycles such as benzimidazole, and quinazolinone via intermolecular amidation reaction followed by cyclization. TEM images of the CuI-NP catalyst showed spherical, well-dispersed particles which provide large surface area for reactivity and have good recyclability. This journal is
- Kumar, Atul,Bishnoi, Ajay Kumar
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p. 41631 - 41635
(2014/12/10)
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- Gold nanoparticles assisted formation of cobalt species for intermolecular hydroaminomethylation and intramolecular cyclocarbonylation of olefins
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The intermolecular hydroaminomethylation and the intramolecular cyclocarbonylation efficiently proceeded on cobalt oxide supported gold nanoparticles. The intermolecular reaction employing terminal olefins and N-isopropylaniline afforded hydroaminomethylated products as a mixture of regioisomers via a common reaction path consisting of hydroformylation, imine formation, and hydrogenation. In contrast, indolinone derivatives were exclusively obtained in the case of 2-alkenylanilines based on the intramolecular cyclocarbonylation mechanism. Both of these reactions were catalyzed by cobalt species derived from cobalt oxide. The active cobalt species were formed via reduction of the oxide support promoted by deposited gold nanoparticles. Characterization of the catalysts before and after the reaction was also performed.
- Liu, Xiaohao,Hamasaki, Akiyuki,Yamane, Yoshihiro,Aikawa, Shohei,Ishida, Tamao,Haruta, Masatake,Tokunaga, Makoto
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p. 3000 - 3006
(2013/11/06)
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- Heterogeneous CuII-catalysed solvent-controlled selective N-arylation of cyclic amides and amines with bromo-iodoarenes
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A selective N-arylation of cyclic amides and amines in DMF and water, respectively, catalysed by CuII/Al2O3 has been achieved. This protocol has been employed for the synthesis of a library of arenes bearing a cyclic amide and an amine moiety at two ends, including a few scaffolds of therapeutic importance. The mechanism has been established based on detailed electron paramagnetic resonance (EPR) spectroscopy, X-ray photoelectron spectroscopy (XPS), UV diffuse reflectance spectroscopy (DRS) and inductively coupled plasma-mass spectrometry (ICP-MS) studies of the catalyst at different stages of the reaction. The CuII/Al2O 3 catalyst was recovered and recycled for subsequent reactions. One over the other: A selective N-arylation of cyclic amides and amines in DMF and water, respectively, catalyzed by CuII/Al2O3 has been achieved (see scheme). This protocol has been employed for the synthesis of a library of arenes bearing cyclic amide and amine moieties at two ends including a few scaffolds of therapeutic importance. The mechanism has been established based on detailed spectroscopic studies (FG=functional group). Copyright
- Kundu, Debasish,Bhadra, Sukalyan,Mukherjee, Nirmalya,Sreedhar, Bojja,Ranu, Brindaban C.
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p. 15759 - 15768
(2013/11/19)
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- Copper(I) complexes with trispyrazolylmethane ligands: Synthesis, characterization, and catalytic activity in cross-coupling reactions
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Three novel Cu(I) complexes bearing tris(pyrazolyl)methane ligands, Tpmx, have been prepared from reactions of equimolar amounts of CuI and the ligands Tpm, (HC(pz)3), Tpm, (HC(3,5-Me2-pz) 3), and TpmMs, (HC(3-Ms-pz)3). X-ray diffraction studies have shown that the Tpm and TpmMs derivatives exhibit a 2:1 Cu:ligand ratio, whereas the Tpm* complex is a mononuclear species in nature. The latter has been employed as a precatalyst in the arylation of amides and aromatic thiols with good activity. The synthesis of a TpmCu(I)-phthalimidate, a feasible intermediate in this catalytic process, has also been performed. Low temperature 1H NMR studies in CDCl 3 have indicated that this complex exists in solution as a mixture of two, neutral and ionic forms. Conductivity measurements have reinforced this proposal, the ionic form predominating in a very polar solvent such as DMSO. The reaction of TpmCu(I)-phthalimidate with iodobenzene afforded the expected C-N coupling product in 76% yield accounting for its role as an intermediate in this transformation.
- Haldon, Estela,Alvarez, Eleuterio,Nicasio, M. Carmen,Perez, Pedro J.
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experimental part
p. 8298 - 8306
(2012/09/22)
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- Palladium-catalyzed amidation of aryl halides using 2-dialkylphosphino- 2′-alkoxyl-1,1′-binaphthyl as ligands
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Palladium-catalyzed intermolecular C-N bond-forming reactions between aryl halides and amides are described using 2-dialkylphosphino-2′-alkoxyl-1, 1′-binaphthyl, which is both bulky and electron-rich, as the ligand. A variety of amides, including aliphatic and aromatic primary amides, lactams, and carbamates, were viable substrates for the amidation, which exhibited good functional group compatibility. By tuning the substituents at the 2,2′-position of 1,1′-binaphthyl of the ligand, the palladium-catalyzed amidation of bulky aryl halides was realized and this coupling reaction was used to synthesize 2-amino-2′-methoxy-1,1′- binaphthyl in high yield.
- Ma, Fangfang,Xie, Xiaomin,Zhang, Lei,Peng, Zhiyong,Ding, Lina,Fu, Lei,Zhang, Zhaoguo
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experimental part
p. 5279 - 5285
(2012/08/07)
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- New synthetic routes for N-substituted 1,n-diamines. II. Synthesis of selectively N-substituted tetra- and pentamethylenediamines from ω-alkanoic acid derivatives
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A new approach for the synthesis of selectively N-substituted tetra- and pentamethylenediamines 1 (n = 4,5) is described. The method uses N-substituted ω-haloalkanamides 2 as precursors and involves the microwave-promoted conversion into ω-azidocarboxamides 3 and later the reduction of both azido and carboxamide groups with diborane.
- Ramírez, María A.,Corona, María V.,Ortiz, Gisela,Salerno, Alejandra,Perillo, Isabel A.,Blanco, María M.
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supporting information; experimental part
p. 1466 - 1468
(2011/06/10)
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