- Pd PEPPSI-IPr-mediated reactions in metal-coated capillaries under MACOS: The synthesis of indoles by sequential aryl amination/heck coupling
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A method has been devised for the microwave-assisted, continuous-flow preparation of indole alkaloids by a two-step aryl amination/cross-coupling sequence of bromoalkenes and 2-bromoanilines. This process requires both the presence of a metal-lined flow tube (a 1180 micron capillary) and the Pd PEPPSI-IPr catalyst; without either, the catalyst or the film, there is zero turnover of this catalytic process. A silver film has been shown to provide some conversion (48-62%), but optimal results (quantitative) across a variety of bromoalkenes and bromoanilines were achieved by using a highly porous palladium film. Possible roles for the Pd film are considered, as is the interplay of the catalyst and the film.
- Shore, Gjergji,Morin, Sylvie,Mallik, Debasis,Organ, Michael G.
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- Tandem Wittig – Reductive annulation decarboxylation approach for the synthesis of indole and 2-substituted indoles
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A simple tandem Wittig reaction-reductive decarboxylation route is established for the synthesis of indoles from commercially available o-nitrobenzaldehydes and a stable phosphorane. The method allows access to indoles in a very fast manner without involving any metal or expensive reagents or inert atmosphere. Also 2-substituted indoles are obtained which forms an important core of many biological active compounds.
- Volvoikar, Prajesh S.,Tilve
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supporting information
p. 1851 - 1854
(2018/04/14)
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- Acceptorless Dehydrogenation of N-Heterocycles and Secondary Alcohols by Ru(II)-NNC Complexes Bearing a Pyrazoyl-indolyl-pyridine Ligand
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Ruthenium(II) hydride complexes bearing a pyrazolyl-(2-indol-1-yl)-pyridine ligand were synthesized and structurally characterized by NMR analysis and X-ray single crystal crystallographic determinations. These complexes efficiently catalyzed acceptorless dehydrogenation of N-heterocycles and secondary alcohols, respectively, exhibiting highly catalytic activity with a broad substrate scope. The present work has established a strategy to construct highly active transition metal complex catalysts and provides an atom-economical and environmentally benign protocol for the synthesis of aromatic N-heterocyclic compounds and ketones.
- Wang, Qingfu,Chai, Huining,Yu, Zhengkun
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p. 584 - 591
(2018/03/08)
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- Synthesis of Indoles by Palladium-Catalyzed Reductive Cyclization of β-Nitrostyrenes with Carbon Monoxide as the Reductant
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An efficient catalytic cyclization of β-nitrostyrenes to indoles was developed. The reaction was applied to the synthesis of 3-arylindoles and 2-alkylindoles. Given that in the latter case the starting β-nitrostyrenes can be easily obtained by a Henry reaction, the present method allows indoles to be obtained in a two-step sequence starting from cheap reactants.
- Ferretti, Francesco,El-Atawy, Mohamed A.,Muto, Stefania,Hagar, Mohamed,Gallo, Emma,Ragaini, Fabio
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supporting information
p. 5712 - 5715
(2015/09/15)
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- 3-(o-Trifluoroacetamidoaryl)-1-propargylic esters: common intermediates for the palladium-catalyzed synthesis of 2-aminomethyl-, 2-vinylic, and 2-alkylindoles
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3-(o-Trifluoroacetamidoaryl)-1-propargylic esters have been used as common synthetic intermediates for the preparation of a variety of 3-unsubstituted 2-substituted indoles. Treating ethyl 3-(o-trifluoroacetamidoaryl)-1-propargylic carbonates unsubstituted or containing an aryl substituent at the propargylic carbon with piperazines and Pd(PPh3)4 in THF at 80 °C affords 2-(piperazin-1-ylmethyl)indoles in excellent yields. Good to excellent yields of 2-aminomethylindoles are also obtained with other secondary amines. Ethyl 3-(o-trifluoroacetamidoaryl)-1-propargylic carbonates bearing an alkyl substituent at the propargylic carbon and ethyl 3-(o-trifluoroacetamidoaryl)-1-propargylic acetates disubstituted at the propargylic carbon give 2-vinylic indoles with the Pd(OAc)2/PPh3 combination and Et3N in THF at 80 °C. Formation of 2-vinylic indoles is quite stereoselective, generating trans vinylic derivatives, at least with the substrates that we have investigated. In the presence of formic acid, Et3N, and Pd(PPh3)4 in MeCN at 80 °C, ethyl 3-(o-trifluoroacetamidoaryl)-1-propargylic carbonates afford 2-alkylindoles in good to excellent yields.
- Ambrogio, Ilaria,Cacchi, Sandro,Fabrizi, Giancarlo,Prastaro, Alessandro
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scheme or table
p. 8916 - 8929
(2009/12/07)
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- Process for producing indole compound
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There is provided a novel process for producing an indole derivative which comprises cyclizing 2-nitrobenzylcarbony compound in the presence of a catalyst comprising a Group VIII metal of the Periodic Table, characterized by conducting the cyclization in a gas atmosphere containing carbon monoxide. The process enables an indole compound to be selectively produced in a high yield from 2-nitrobenzylcarbonyl compound, and hardly yields an indoline compound as a reduction by-product that has been a problem in the catalytic hydrogenation method employing a noble metal catalyst. The indole derivative produced by the present process is useful for various fine chemical intermediates including compounds and physiologically active substances such as pharmaceuticals and agrochemicals.
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Page/Page column 7
(2008/06/13)
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- 2-Alkylindoles via palladium-catalyzed reductive cyclization of ethyl 3-(o-trifluoroacetamidophenyl)-1-propargyl carbonates
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The reaction of ethyl 3-(o-trifluoroacetamidophenyl)-1-propargyl carbonates with formate anions in the presence of Pd(PPh3)4 affords 2-alkylindoles in good to excellent yields.
- Ambrogio, Ilaria,Cacchi, Sandro,Fabrizi, Giancarlo
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p. 7721 - 7725
(2008/03/30)
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- Ruthenium-catalyzed heteroannulation of anilines with alkanolammonium chlorides leading to indoles
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Anilines react with alkanolammonium chlorides in an aqueous medium (H2O-dioxane) at 180°C in the presence of a catalytic amount of a ruthenium catalyst together with SnCl2·2H2O to afford the corresponding indoles in moderate to good yields. Especially, when triisopropanolammonium chloride is employed to react with anilines, 2-methylindoles are formed regioselectively. The presence of SnCl2·2H2O is necessary for the effective formation of indoles. A reaction pathway involving alkanol group transfer from alkanolamines to anilines, N-alkylation of anilines by anilinoalkanols and heteroannulation of 1,2-dianilinoalkanes is proposed for this catalytic process.
- Cho, Chan Sik,Kim, Jin Hwang,Kim, Tae-Jeong,Shim, Sang Chul
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p. 3321 - 3329
(2007/10/03)
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- Ruthenium-catalysed synthesis of indoles from anilines and trialkanolamines in the presence of tin(II) chloride dihydrate
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Anilines react with trialkanolamines in dioxane in the presence of a catalytic amount of a ruthenium catalyst together with tin(II) chloride dihydrate to give the corresponding indoles in moderate to good yields.
- Cho, Chan Sik,Lim, Hyo Kyun,Shim, Sang Chul,Kim, Tae Jeong,Choi, Heung-Jin
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p. 995 - 996
(2007/10/03)
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- Unusual acetylation of 2-methyl-1-phenylsulfonylindole
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Acetylation of 2-methyl-1-phenylsulfonylindole with an excess of aluminium chloride and acetic anhydride afforded exclusively 6-acetyl-3-chloro-2-methylindole and 6-acetyl-3-chloro-2-methyl-1-phenylsulfonylindole.
- Merour, Jean-Yves,Malapel, Beatrice,Desarbre, Eric
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p. 3267 - 3276
(2007/10/03)
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- Substituted N-aryl alk-1-enesulfinamides: Preparation, properties and conversion into the corresponding indole compounds [1]
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Reaction of vinylic organometallic derivatives with N-sulfinyl arenamines 2 affords the title sulfinamides 3. On heating their solutions in selected solvents to 80-124 °C, these sulfinamides are converted into the corresponding indoles 6, probably via a [3.3]-sigmatropic rearrangement to intermediates VIII which undergo an intramolecular carbophilic reaction of the nitrogen atom with the neighboring sulfine group, followed by elimination of HSOH. The triethyloxonium tetrafluoroborate- or boron trifluoride etherate catalyzed conversion 3 → 6 can be carried out at a much lower temperature. Elsevier,.
- Baudin, Jean-Bernard,Commenil, Marie-Gabrielle,Julia, Sylvestre A.,Lorne, Robert,Mauclaire, Laurent
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p. 329 - 350
(2007/10/03)
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