5782-14-9Relevant academic research and scientific papers
A palladium-catalyzed Barluenga cross-coupling – Reductive cyclization sequence to substituted indoles
Rahman, S. M. Ashikur,S?derberg, Bj?rn C. G.
, (2021/07/20)
A short and flexible synthesis of substituted indoles employing two palladium-catalyzed reactions, a Barluenga cross-coupling of p-tosylhydrazones with 2-nitroarylhalides followed by a palladium–catalyzed, carbon monoxide–mediated reductive cyclization has been developed. A one-pot, two-step methodology was further developed, eliminating isolation and purification of the cross-coupling product. This was accomplished by utilizing the initially added 0.025 equivalents of bis(triphenylphosphine)palladium dichloride, thus serving a dual role in the cross-coupling and the reductive cyclization. It was found that addition of 1,3-bis(diphenylphosphino)propane and carbon monoxide after completion of the Barluenga reaction afforded, in most cases, significantly better overall yields.
Synthesis and antimycobacterial activity of 3-phenyl-1h-indoles
Abbadi, Bruno Lopes,Basso, Luiz Augusto,Bizarro, Cristiano Valim,Dornelles, Maiele,Duarte, Lovaine,Etchart, Renata Jardim,Lourega, Rogério Vescia,Macchi, Fernanda Souza,Machado, Pablo,Neves, Christiano Ev,Perelló, Marcia Alberton,Rambo, Raoní S.,Silva, Fernanda Fries,Sperotto, Nathalia
, (2021/08/31)
Tuberculosis has been described as a global health crisis since the 1990s, with an estimated 1.4 million deaths in the last year. Herein, a series of 20 1H-indoles were synthesized and evaluated as in vitro inhibitors of Mycobacterium tuberculosis (Mtb) g
FeCl3 catalyzed intermolecular reaction between enol ethers and anilines: Access to 2,3-substituted indoles through aryl group migration
Jena, Tapan Kumar,Khan, Faiz Ahmed
supporting information, (2020/11/10)
An intermolecular FeCl3 catalyzed reaction between anilines and enol ethers is described. A variety of enol ethers and aromatic amines undergo a C[sbnd]C bond formation followed by cyclization via C[sbnd]N bond formation to afford the 2,3-disubstituted indoles, involving an unexpected aryl group migration. In this methodology, anilines act as bis-nucleophiles, wherein the initial attack occurs at the α-position of enol ether from the ortho position of aniline followed by the subsequent reaction of the amine moiety of aniline at the β-position, leading to the indole framework. This method is simple, obviates the use of expensive/hazardous transition-metal catalysts, and offers a wide range of substrate scope.
Preparation method of indole compound
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Paragraph 0093-0094, (2020/12/29)
The invention discloses a preparation method of a novel efficient indole compound, which comprises the following steps: by using o-nitroalkylbenzene containing various substituents as a raw material,controlling the reaction temperature to be 70-160 DEG C in an organic solution under the protection of inert gas and the participation of inorganic base, thereby obtaining the indole compound; preparing the novel indole compound containing various substituent groups through a hydrocarbon activation reaction catalyzed by a metal rhodium catalyst. The synthetic method is not reported in literature,the raw materials are easy to synthesize, no reducing agent needs to be added additionally, the method is simple in step, the indole compound containing various substituent groups does not need to beconstructed in one step through a nitroso intermediate, and the yield is high; The method is simple in unit operation, low in equipment requirement and suitable for rapidly synthesizing the indole compounds containing various substituent groups.
Pd-catalyzed C–H bond activation of Indoles for Suzuki reaction
Banerjee, Isita,Ghosh, Keshab Ch,Sinha, Surajit
, (2019/08/22)
Abstract: We present a practical method for Suzuki coupling by which unprotected or N-protected indoles may be selectively arylated in the C2-position through direct C–H bond activation by electrophilic Pd(TFA) 2 catalyst. The protocol is operationally simple as it is carried out in dioxane/water mixture, and air as the sole oxidant at room temperature. Various 2-arylated indoles were obtained in good yields. The protocol works for benzofuran, pyrrole and thiophene also. Graphic abstract: Selective C-2 arylation of heterocycles using Pd(II) catalyst via C–H activation was performed under ambient condition. C3–C2 migration of organopalladium intermediate controls the reaction pathway.[Figure not available: see fulltext.].
Aqueous Titanium Trichloride Promoted Reductive Cyclization of o-Nitrostyrenes to Indoles: Development and Application to the Synthesis of Rizatriptan and Aspidospermidine
Tong, Shuo,Xu, Zhengren,Mamboury, Mathias,Wang, Qian,Zhu, Jieping
supporting information, p. 11809 - 11812 (2015/10/05)
Treatment of o-nitrostyrenes with aqueous TiCl3 solution at room temperature afforded indoles through a formal reductive C(sp2)-H amination process. A range of functions such as halides (Cl, Br), carbonyl (ester, carbamate), cyano, hydroxy, and amino groups were tolerated. From β,β-disubstituted o-nitrostyrenes, 2,3-disubstituted indoles were formed by a domino reduction/cyclization/migration process. Mild conditions, simple experimental procedure, ready accessibility of the starting materials and good to excellent yields characterize the present transformation. The methodology was used as a key step in a concise synthesis of rizatriptan and a formal total synthesis of aspidospermidine. Mild and efficient treatment of o-nitrostyrenes with aqueous TiCl3 solution at room temperature afforded indoles through a formal reductive C(sp2)-Hamination process. A concise synthesis of a marketed drug (rizatriptan) and a formal total synthesis of aspidospermidine featuring this novel N-heterocyclization process are reported.
Metal-free direct arylations of indoles and pyrroles with diaryliodonium salts
Ackermann, Lutz,Dellacqua, Monica,Fenner, Sabine,Vicente, Ruben,Sandmann, Rene
supporting information; experimental part, p. 2358 - 2360 (2011/06/25)
Chemical equations presented. Direct arylations of indoles and pyrroles with differently substituted diaryliodonium salts were shown to efficiently proceed in the absence of metal catalysts.
Direct palladium-catalyzed C-3 arylation of free (NH)-indoles with aryl bromides under ligandless conditions
Bellina, Fabio,Benelli, Francesca,Rossi, Renzo
, p. 5529 - 5535 (2008/12/20)
(Chemical Equation Presented) A new method for the efficient, practical, and highly regioselective direct palladium-catalyzed C-3 arylation of free (NH)-indole and its electron-rich 1-unsubstituted derivatives under ligandless conditions is described. The reactions, which are run outside a glovebox without purification of solvent and reagents, involve treatment of free (NH)-indoles with activated, unactivated, and deactivated aryl bromides in refluxing toluene in the presence of K2CO3 as the base and a catalyst system consisting of a combination of Pd(OAc)2 and benzyl(tributyl)ammonium chloride. The experimental results are consistent with a catalytic cycle based on an electrophilic palladation pathway at the 3-position of 1-indolyl potassium salts.
The Neber route to substituted indoles
Taber, Douglass F.,Tian, Weiwei
, p. 1058 - 1059 (2007/10/03)
Two complementary procedures have been developed for the conversion of the oximes of α-aryl ketones to azirines. On heating, the azirines rearrange smoothly to the corresponding indoles. The overall transformation offers a versatile route to indoles, complementary to the Fischer indole synthesis. Copyright
2-Substituted-3-acylindoles through the palladium-catalysed carbonylative cyclization of 2-alkynyltrifluoroacetanilides with aryl halides and vinyl triflates
Arcadi,Cacchi,Carnicelli,Marinelli
, p. 437 - 452 (2007/10/02)
The palladium-catalysed reaction of readily accessible 2- alkynyltrifluoroacetanilides with aryl halides and vinyl triflates under a carbon monoxide atmosphere (1 or 7 atm) and in the presence of potassium carbonate produces 2-substituted-3-acyl indoles in fair to good yield. The acidity of the nitrogen-hydrogen bond proved to be of primary importance for the success of the reaction. The methodology has been applied to the synthesis of pravadoline, a drug that shows analgesic activity against postoperative pain in man.
