cas 3469-20-3, 2,3-Diphenylindole | Articles data

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The first regioselective palladium-catalyzed indolization of 2-bromo- or 2-chloroanilines with internal alkynes: A new approach to 2,3-disubstituted indoles
(Chemical Equation Presented) The first practical and economical process for synthesis of 2,3-disubstituted indole compounds has been developed with high regioselectivity by palladium-catalyzed indolization of 2-bromo- or chloroanilines and their derivatives with internal alkynes.
Shen, Ming,Li, Guisheng,Lu, Bruce Z.,Hossain, Azad,Roschangar, Frank,Farina, Vittorio,Senanayake, Chris H.
p. 4129 - 4132
(2004)
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2,3-Disubstituted indoles through the palladium-catalyzed reaction of aryl chlorides with o-alkynyltrifluoroacetanilides
2,3-Disubstituted indoles can be prepared in moderate to excellent yields by reacting readily available o-alkynyltrifluoroacetanilides with aryl chlorides in MeCN at 120°C in the presence of Pd2(dba)3 and Xphos.
Cacchi, Sandro,Fabrizi, Giancarlo,Goggiamani, Antonella
p. 1301 - 1305
(2006)
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Rhodium(I)-catalyzed Addition of Tolane to Azobenzene: A New Route to Indole Derivatives
RhCl(PPh3)3 catalyzes the formation of N-anilino-2,3-diphenylindole (1) and small amounts of 2,3-diphenylindole (2) from azobenzene and diphenylacetylene.Weak acids or silica gel accelerate the reaction and induce an almost quantitative conversion to 1.Other rhodium(I) complexes are less active while rhodium(III) compounds inhibit the reaction.A preliminary reaction mechanism of the homogeneous catalysis is proposed and the structure of two key intermediates is substantiated by ab initio MO calculations. - Keywords: Azobenzene; Diphenylacetylene; Indoles; Rhodium(I)-catalysis; Silica gel supported catalysis.
Reisser, P.,Wakatsuki, Y.,Kisch, H.
p. 1 - 12
(1995)
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Annulation of internal alkynes through a hydroamination/aza-Heck reaction sequence for the regioselective synthesis of indoles
Highly regioselective annulation reactions of unsymmetrically substituted alkynes by primary 2-bromo or 2-chloroanilines are achieved with an efficient one-pot protocol, which relies on a regioselective TiCl4-catalyzed intermolecular hydroamination and a subsequent palladium-catalyzed intramolecular aza-Heck reaction. The use of unsymmetrically substituted alkynes in this strategy enables the synthesis of diversely functionalized indoles, with a regioselectivity that is complementary to the one obtained when employing Larock's annulation reaction.
Ackermann, Lutz,Sandmann, René,Villar, Amparo,Kaspar, Ludwig T.
p. 769 - 777
(2008)
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Synthesis of indolo[2,1-a]isoquinolines via a triazene-directed C-H annulation cascade
(Chemical Equation Presented) Indole-containing polyaromatic scaffolds are widely found in natural products, pharmaceutical agents, and π-conjugated functional materials. Often, the synthesis of these highly valuable molecules requires a multistep sequence. Therefore, a simple, one-step protocol to access libraries of polyaromatic indole scaffolds is highly desirable. Herein we describe the direct synthesis of polysubstituted indolo[2,1-a]isoquinoline analogues via a double C-H annulation cascade using triazene as an internally cleavable directing group. Evidence from HRMS and theoretical calculations suggests that an unprecedented 1,2-alkyl migration might be responsible for the in situ cleavage of the directing group. Both kinetic isotope effects and DFT calculations suggested that the alkyne insertion step is rate-limiting for the second C,N annulation reaction.
Sun, Huan,Wang, Chengming,Yang, Yun-Fang,Chen, Ping,Wu, Yun-Dong,Zhang, Xinhao,Huang, Yong
p. 11863 - 11872
(2014)
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Transition Metal Complexes of Diazenes XXXVI [1a]: Formation of Indoles from Azobenzene and Diphenylacetylene through Supported Aqueous Phase Catalysis by Rhodium(I) Complexes
A SiO2 supported Rh(I) catalyst of trisulfonated triphenylphosphine catalyzes the addition of diphenylacetylene to azobenzene in refluxing butanol in the presence of triphenylphosphine to afford N-anilino-2,3-diphenylindole and 2,3-diphenylindole with turnover numbers of 80 and 20, respectively. As compared to the known homogeneous or heterogeneous (SiO2) catalysis by RhCl(PPh3)3, the supported aqueous phase system retains a constant turnover frequency throughout the reaction and can be partially recycled.
Westernacher,Kisch
p. 469 - 473
(1996)
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Rh(III)-catalyzed coupling of nitrones with alkynes for the synthesis of indolines
Rh-catalyzed redox-neutral coupling between N-aryl nitrones and alkynes has been achieved under relatively mild conditions. The reaction proceeded via C-H activation at the N-aryl ring with subsequent O-atom transfer, affording trisubstituted indolines in good chemoselectivity and moderate to good diasteroselectivity.
Kong, Lingheng,Xie, Fang,Yu, Songjie,Qi, Zisong,Li, Xingwei
p. 925 - 932
(2015)
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Uebergangsmetallkomplexe von Diazenen. XXXI. Orthometallierte Diazenkomplexe von Molybdaen, Eisen und Ruthenium: Struktur und Umsetzung zu 2,3-Diphenylindol
Irradiation of *Ru(CO)2>2 or Cp*Ru(CO)2CH3 (Cp* = C5Me5) in the presence of azobenzene or 4,4'-dimethylazobenzene affords orthometallated Cp*Ru(pap)(CO) (pap = (phenylazo)phenyl) and Cp*Ru(4,4'-dmp
Garn, Dieter,Knoch, Falk,Kisch, Horst
p. 155 - 164
(1993)
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Chiral-Phosphoric-Acid-Catalyzed C6-Selective Pictet-Spengler Reactions for Construction of Polycyclic Indoles Containing Spiro Quaternary Stereocenters
Compared with the well-established asymmetric Pictet-Spengler reactions on the pyrrole ring of indoles, the catalytic asymmetric Pictet-Spengler reaction on the benzene ring of indoles has been rarely studied. Herein the C6-selective Pictet-Spengler react
Huang, Wen-Jun,Wang, Han,Wang, Xin-Wei,Wu, Bo,Zhou, Yong-Gui
supporting information
p. 1727 - 1731
(2022/03/14)

Electrochemical Tri- and Difluoromethylation-Triggered Cyclization Accompanied by the Oxidative Cleavage of Indole Derivatives
Considering their unique roles in organic synthesis, and pharmaceutical and agrochemical applications, the development of fluoroalkylation, cyclization, and indole oxidative cleavage are important topics. Herein, an unprecedented electrochemical tri- and difluoromethylation/cyclization/indole oxidative cleavage process occurring in an undivided cell is presented. The protocol employs a readily prepared Langlois reagent as the fluoroalkyl source, affording a series of tri- or difluoromethylated 2-(2-acetylphenyl)isoquinoline-1,3-diones in good yields with excellent stereoselectivity. It is worth noting that this new methodology merges the fluoroalkylation/cyclization of N-substituted acrylamide alkenes with the oxidative cleavage of an indole C(2)=C(3) bond under external oxidant-free conditions.
Yuan, Xin,Cui, Yu-Sheng,Zhang, Xin-Peng,Qin, Long-Zhou,Sun, Qi,Duan, Xiu,Chen, Lin,Li, Guigen,Qiu, Jiang-Kai,Guo, Kai
supporting information
p. 6522 - 6528
(2021/03/16)

Visible-Light Photocatalytic Tri- A nd Difluoroalkylation Cyclizations: Access to a Series of Indole[2,1- A[isoquinoline Derivatives in Continuous Flow
A process for achieving photocatalyzed tri- A nd difluoromethylation/cyclizations for constructing a series of tri-or difluoromethylated indole[2,1-a]isoquinoline derivatives is described. This protocol utilized an inexpensive organic photoredox catalyst and provided good yields. Moreover, the combination of continuous flow and photochemistry, designed to provide researchers with a unique green process, was also shown to be key to allowing the reaction to proceed (product yield of 83% in flow vs 0% in batch).
Yuan, Xin,Duan, Xiu,Cui, Yu-Sheng,Sun, Qi,Qin, Long-Zhou,Zhang, Xin-Peng,Liu, Jie,Wu, Meng-Yu,Qiu, Jiang-Kai,Guo, Kai
supporting information
p. 1950 - 1954
(2021/04/05)

Rhodium-Catalyzed Annulation of N-Acetoxyacetanilide with Substituted Alkynes: Conversion of Nitroarenes to Substituted Indoles
A general and efficient rhodium-catalyzed redox-neutral annulation of N-acetoxyacetanilides, readily accessible from nitroarenes, with alkynes has been accomplished for the synthesis of substituted indole derivatives. A wide range of substituted 2,3-diarylindoles were achieved from various substituted N-acetoxyacetanilides and symmetrical/unsymmetrical alkynes in good to excellent yields. The developed method was successfully integrated with the synthesis of N-acetoxyacetanilides for the efficient one-pot synthesis of indoles from nitroarenes. The important features are the introduction of N-acetoxyacetamide as a new directing group, redox-neutral annulation, an additive-free approach, wide functional group tolerance, an intramolecular version, and a one-pot reaction of nitroarenes. The method was further extended to the synthesis of potent higher analogues of indole, viz., pyrrolo[3,2-f]indoles and dibenzo[a,c]carbazoles. In addition, a plausible mechanism was proposed based on the isolation and stoichiometric study of a potential aryl-Rh intermediate.
Ghorai, Jayanta,Ramachandran, Kuppan,Anbarasan, Pazhamalai
p. 14812 - 14825
(2021/10/25)

Sequential Sonogashira/intramolecular aminopalladation/cross-coupling ofortho-ethynyl-anilines catalyzed by a single palladium source: rapid access to 2,3-diarylindoles
We have developed a practical and efficient one-pot protocol for the synthesis of 2,3-diarylindolesviaPd-catalyzed bis-arylative cyclization of variouso-ethynylanilines with aryl iodides. Mechanism studies showed that a Pd-catalyzed Sonogashira reaction took place firstly, giving an internal alkyne intermediate, which subsequently underwent intramolecular aminopalladation/cross-coupling to give access to 2,3-diarylindoles. The present methodology exhibits a broad substrate scope, producing various 2,3-diaryl indoles bearing two different aryl groups.
Wang, Jiwei,Wang, Gendi,Cheng, Xiang,Liu, Ye,Zhang, Jun
supporting information
p. 1329 - 1333
(2021/02/26)

Synthesis of Unprotected and Highly Substituted Indoles by the Ruthenium(II)-Catalyzed Reaction of Phenyl Isocyanates with Diaryl/Diheteroaryl Alkynes/Ethyl-3-phenyl Propiolates
A one-pot transformation has been developed for the synthesis of unprotected and highly substituted indoles by an in situ installed carbamide-directed Ru(II)-catalyzed intermolecular oxidative annulation of phenyl isocyanates with diaryl/diheteroaryl alkynes/ethyl phenyl propiolates in the presence of Cu(OAc)2·H2O as an oxidant and AgSbF6 as an additive at 120 °C within 3 h.
Kumar, Amrendra,Tadigoppula, Narender
supporting information
p. 8 - 12
(2021/01/13)

Manganese(iii)-promoted tandem phosphinoylation/cyclization of 2-arylindoles/2-arylbenzimidazoles with disubstituted phosphine oxides
A simple and practical method for the synthesis of phosphoryl-substituted indolo[2,1-a]isoquinolin-6(5H)-ones and benzimidazo[2,1-a]isoquinolin-6(5H)-ones through manganese(iii)-promoted tandem phosphinoylation/cyclization of 2-arylindoles or 2-arylbenzimidazoles with disubstituted phosphine oxides was developed. In this transformation, new C-P bond and C-C bond were constructed simultaneously under silver-free conditions, exhibiting a broad substrate scope. It was noted that not only diarylphosphine oxides but also dialkyl and arylalkyl-phosphine oxides were compatible with the conditions. This journal is
Jiang, Shuai-Shuai,Li, Jin-Heng,Luo, Shu-Zheng,Song, Ren-Jie,Wu, Yan-Chen,Xiao, Yu-Ting
supporting information
p. 4843 - 4847
(2020/07/13)

Heterocyclic compounds and organic light-emitting diode including the same
The present invention relates to a novel heterocyclic compound and an organic electroluminescent device including the same as a light emitting material, specifically a heterocyclic compound denoted by chemical formula 1, and an organic electroluminescent device having excellent luminance properties including driving voltage and luminance efficiency.
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Paragraph 0288; 0325-0330; 0366-0372

(2020/11/20)

Et3SiH + KO: T Bu provide multiple reactive intermediates that compete in the reactions and rearrangements of benzylnitriles and indolenines
The combination of potassium tert-butoxide and triethylsilane is unusual because it generates multiple different types of reactive intermediates simultaneously that provide access to (i) silyl radical reactions, (ii) hydrogen atom transfer reactions to cl
Arokianathar, Jude N.,Clark, Kenneth F.,Dimitrova, Daniela,Leach, Stuart G.,Murphy, John A.,Poole, Darren L.,Smith, Andrew J.
p. 12364 - 12370
(2020/12/08)

Characterization of heterogeneous aryl-Pd(ii)-oxo clusters as active species for C-H arylation
C-H arylation with heterogeneous palladium was investigated. The surface oxidation of Pd nanoparticles with a hypervalent iodine reagent, [Ph2I]BF4, resulted in the generation of Pd(ii)-aryl-oxo clusters, which were characterized as the crucial intermediate.
Shin, Taeil,Kim, Minjun,Jung, Younjae,Cho, Sung June,Kim, Hyunwoo,Song, Hyunjoon
supporting information
p. 14404 - 14407
(2020/12/01)

Step and redox efficient nitroarene to indole synthesis
Step and redox efficiencies are a rising priority in synthetic method development, in order to make synthetic processes more sustainable and more affordable. Herein, a step and redox efficient nitroarene to indole synthesis is developed, in sharp contrast to the rich literature on the construction of indoles. Elemental zinc was found to be the best terminal reductant. This journal is
?zkaya, Bünyamin,Bub, Christina L.,Patureau, Frederic W.
supporting information
p. 13185 - 13188
(2020/11/09)

Acid mediated coupling of aliphatic amines and nitrosoarenes to indoles
Traditionally, amines react with nitrosoarenes to provide the corresponding imines or azo compounds. Herein, we report an acid mediated annulation reaction of aliphatic amines and nitrosoarenes to provide indole derivatives. The elusive direct annulation of aliphatic amines and nitrosoarenes via simultaneous C-C and C-N bond formation was achieved under metal free conditions. This conceptually novel method for indole synthesis does not require pre-functionalization steps for the new C-C and C-N bond formation. The method has been applied for an elegant synthesis of nor-neocryptolepine and neocryptolepine.
Roy, Subhra Kanti,Purkait, Anisha,Aziz, Sk Md Tarik,Jana, Chandan K.
supporting information
p. 3167 - 3170
(2020/03/23)

Synthesis of indolo[2,1-: A] isoquinoline derivatives via visible-light-induced radical cascade cyclization reactions
We describe a photocatalyzed transformation for the synthesis of the indolo[2,1-a]isoquinoline core structure. This redox neutral reaction features mild reaction conditions and exceptional functional group tolerance. A series of valuable indolo[2,1-a]isoquinoline derivatives bearing various functional groups were synthesized using this method in good to excellent yields.
Wei, Yun-Long,Chen, Jian-Qiang,Sun, Bo,Xu, Peng-Fei
supporting information
p. 5922 - 5925
(2019/05/27)

Metal-Free Visible-Light Promoted Radical Cyclization to Access Perfluoroalkyl-Substituted Benzimidazo[2,1-a]isoquinolin-6(5H)-ones and Indolo[2,1-a]isoquinolin-6(5H)-ones
A metal-free visible-light-induced cyclization procedure was developed for the rapid synthesis of perfluoroalkyl-substituted benzimidazo[2,1-a]isoquinolin-6(5H)-ones and perfluoroalkyl-substituted indolo[2,1-a]isoquinolin-6(5H)-ones under mild reaction conditions. In this procedure, the formation of electron-donor-acceptor (EDA) complex is critical for the visible-light promoted process to avoid the utilization of external photocatalysts. (Figure presented.).
Zeng, Fan-Lin,Sun, Kai,Chen, Xiao-Lan,Yuan, Xiao-Ya,He, Shuai-Qi,Liu, Yan,Peng, Yu-Yu,Qu, Ling-Bo,Lv, Qi-Yan,Yu, Bing
supporting information
p. 5176 - 5181
(2019/11/11)

Predicting the Outcome of Photocyclisation Reactions: A Joint Experimental and Computational Investigation
Photochemical oxidative cyclodehydrogenation reactions are a versatile class of aromatic ring-forming reactions. They are tolerant to functional group substitution and heteroatom inclusion, so can be used to form a diverse range of extended polyaromatic systems by fusing existing ring substituents. However, despite their undoubted synthetic utility, there are no existing models—computational or heuristic—that predict the outcome of photocyclisation reactions across all possible classes of reactants. This can be traced back to the fact that “negative” results are rarely published in the synthetic literature and the lack of a general conceptual framework for understanding how photoexcitation affects reactivity. In this work, we address both of these issues. We present experimental data for a series of aromatically substituted pyrroles and indoles, and show that quantifying induced atomic forces upon photoexcitation provides a powerful predictive model for determining whether a given reactant will photoplanarise and hence proceed to photocyclised product under appropriate reaction conditions. The propensity of a molecule to photoplanarise is related to localised changes in charge distribution around the putative forming ring upon photoexcitation. This is promoted by asymmetry in molecular structures and/or charge distributions, inclusion of heteroatoms and ethylene bridging and well-separated or isolated photocyclisation sites.
Wonanke, A. D. Dinga,Ferguson, Jayne L.,Fitchett, Christopher M.,Crittenden, Deborah L.
supporting information
p. 1293 - 1303
(2019/02/25)

Organic electroluminescent compound as well as preparation method and organic electroluminescent device thereof
The invention relates to an organic electroluminescent compound as well as a preparation method and an organic electroluminescent device thereof. The organic electroluminescent compound has a structural formula shown by a chemical formula 1 as shown in the specification. The invention proposes a solution for introducing a novel pyrroloindole derivative. A high-quality organic electroluminescent material with excellent hole transporting capacity, high efficiency and long service life is obtained by introducing arylamine and the novel pyrroloindole derivative. The organic electroluminescent device prepared by using the organic electroluminescent compound provided by the invention as a hole transporting layer has a lower starting voltage by compared with that of the organic electroluminescentdevice prepared by using NPB as the hole transporting layer, the luminous efficiency is improved and the service life is significantly prolonged. The preparation method of the organic electroluminescent compound provided by the invention is simple and feasible, high in yield, and suitable for large-scale production.
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Paragraph 0070-0072

(2019/09/17)

Synthetic method of 2-substituted indoles compounds
The invention discloses a synthetic method of 2-substituted indoles compounds, and belongs to the organic synthesis field. 2-fluorotoluene compound shown in formula 1 and nitrile compound shown in formula 2 mix with an organic solvent in the presence of strong alkali and cesium salt additives, and react to synthesize the 2-substituted indoles compounds shown in formula 3. The synthesis method of 2-substituted indoles compounds is simple, economical and has wider applicability, is suitable for large-scale production, and has a very important influence on the synthesis of indoles compounds.
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Paragraph 0010; 0035-0037; 0041; 0043; 0050

(2019/05/02)

Synthesis of Indoles through Domino Reactions of 2-Fluorotoluenes and Nitriles
Indoles are essential heterocycles in medicinal chemistry, and therefore, novel and efficient approaches to their synthesis are in high demand. Among indoles, 2-aryl indoles have been described as privileged scaffolds. Advanced herein is a straightforward, practical, and transition-metal-free assembly of 2-aryl indoles. Simply combining readily available 2-fluorotoluenes, nitriles, LiN(SiMe3)2, and CsF enables the generation of a diverse array of indoles (38 examples, 48–92 % yield). A range of substituents can be introduced into each position of the indole backbone (C4 to C7, and aryl groups at C2), providing handles for further elaboration.
Mao, Jianyou,Wang, Zhiting,Xu, Xinyu,Liu, Guoqing,Jiang, Runsheng,Guan, Haixing,Zheng, Zhipeng,Walsh, Patrick J.
supporting information
p. 11033 - 11038
(2019/07/08)

Asymmetric N-Hydroxyalkylation of Indoles with Ethyl Glyoxalates Catalyzed by a Chiral Phosphoric Acid: Highly Enantioselective Synthesis of Chiral N,O-Aminal Indole Derivatives
A method of SPINOL-derived chiral phosphoric acid catalyzed asymmetric intermolecular N-hydroxyalkylation of multisubstituted indoles with ethyl glyoxalates is described in this report. This protocol provides an alternative, convenient, and direct strategy for efficient access to structurally unique α-chiral indole N,O-acyclic aminals with a broad substrate scope and good to excellent enantioselectivities. The synthetic utility of this methodology is illustrated by a gram-scale experiment and the subsequent efficient synthesis of more complex chiral N,O-aminal indole derivatives.
Wang, Le,Zhou, Jia,Ding, Tong-Mei,Yan, Zhi-Qiang,Hou, Si-Hua,Zhu, Guo-Dong,Zhang, Shu-Yu
p. 2795 - 2799
(2019/04/30)

One-Pot Reaction between N-Tosylhydrazones and 2-Nitrobenzyl Bromide: Route to NH-Free C2-Arylindoles
A one-pot Barluenga coupling between N-tosylhydrazones and nitro-benzyl bromide, followed by deoxygenation of ortho-nitrostyrenes, and subsequent cyclization has been developed, providing a new way to synthesize various C2-arylindoles. This method exhibits a good substrate scope and functional group tolerance, and it allows an access to NH-free indoles, which can present a potential utility in medicinal chemistry applications.
Bzeih, Tourin,Zhang, Kena,Khalaf, Ali,Hachem, Ali,Alami, Mouad,Hamze, Abdallah
p. 228 - 238
(2019/01/04)

N, N-Dimethylformamide-stabilized palladium nanoclusters as a catalyst for Larock indole synthesis
We show that N,N-dimethylformamide-stabilized Pd nanoclusters (NCs) have high catalytic activity in the reaction of substituted 2-iodoanilines with alkynes to give 2,3-disubstituted indoles. This indole synthesis does not require phosphine ligands and proceeds with low Pd catalyst loadings. The Pd NCs were separated from the mixture after the reaction, and recycled at least three times. Transmission electron microscopy images showed that the Pd particle size before the reaction was 1.5-2.5 nm. The particle size after the reaction was 2-3 nm. X-ray photoelectron spectroscopy showed that the binding energy of the Pd NCs before the reaction was 335.0 eV.
Onishi, Kaito,Oikawa, Kei,Yano, Hiroki,Suzuki, Takeyuki,Obora, Yasushi
p. 11324 - 11329
(2018/04/05)

Arylation synthesis method for novel five-membered aromatic heterocycle and aromatic-ring five-membered aromatic heterocycle
The invention belongs to the technical field of organic synthesis and in particular relates to an arylation synthesis method for a five-membered aromatic heterocycle or an aromatic-ring five-memberedaromatic heterocycle under the participation of an arylhydrazine derivative serving as a novel arylation reagent. The method comprises the steps: adding a raw material and aroyl hydrazine into a reactor, and carrying out a reaction at 60-100 DEG C for 8-24h under the condition that an oxidant and a transition metal catalyst are added; after the reaction is ended, carrying out suction filtration, extracting a filtrate by using ethyl acetate, carrying out drying to obtain a crude product of a target compound, and carrying out column chromatography on silica gel to obtain a pure product of the target compound. The arylation synthesis method for the five-membered aromatic heterocycle or the aromatic-ring five-membered aromatic heterocycle is scientific and reasonable and has the advantages such as simplicity and convenience in operation, relatively high yield and simplicity in amplification and purification.
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Paragraph 0112-0115; 0200-0203

(2018/07/07)

Formal Lossen Rearrangement/[3+2] Annulation Cascade Catalyzed by a Modified Cyclopentadienyl RhIII Complex
It has been established that a cyclopentadienyl RhIII complex with two phenyl groups and a pendant amide moiety catalyzes the formal Lossen rearrangement/[3+2] annulation cascade of N-pivaloyl benzamides and acrylamides with alkynes leading to substituted indoles and pyrroles. Mechanistic studies revealed that this cascade reaction proceeds via not the Lossen rearrangement to form anilides or enamides but C?H bond cleavage, alkyne insertion, and the formal Lossen rearrangement.
Yamada, Takayuki,Shibata, Yu,Kawauchi, Susumu,Yoshizaki, Soichi,Tanaka, Ken
supporting information
p. 5723 - 5727
(2018/04/11)

Synthesis of indoles from aroyloxycarbamates with alkynes: Via decarboxylation/cyclization
An efficient Pd-catalyzed decarboxylation/cyclization of aroyloxycarbamates to realize substituted indoles has been disclosed. Terminal alkynes as the coupling partners lead to site specific 2-substituted indoles through two pathways, while internal alkynes with aroyloxycarbamates can be transformed to 2,3-disubstituted indoles directly. This protocol is further demonstrated by the efficient synthesis of indoles as well as the success of employing inexpensive aryl acids as starting materials to construct C-N bonds by releasing CO2.
Ma, Nuannuan,Li, Peihe,Wang, Zheng,Dai, Qipu,Hu, Changwen
supporting information
p. 2421 - 2426
(2018/04/12)

Method for directly synthesizing indole by using nitrile
The invention discloses a method for directly synthesizing indole by using nitrile. The method is characterized in that a 2-iodotoluene derivative is served as a substrate, anhydrous copper sulfate, potassium tert-butoxide, a cyanophenyl derivative and the 2-iodophene derivative are mixed according to the molar ratio of (0.02-0.1): (2-4): (5-20):1, reaction is carried out for 4-48 hours at 60-105DEG C in a solvent, petroleum ether/dichloromethane/ethyl acetate are mixed according to the volume ratio of (20-5):10:1 so as to be served as an eluent, and separation is carried out by using a silica gel column so as to obtain a target product. The method has the advantages that the operation is simple, the conditions are mild, the yield is high, and the method is a green and novel synthetic method.
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Paragraph 0039-0041

(2018/12/13)

Synthesis of Indoles through Palladium-Catalyzed Three-Component Reaction of Aryl Iodides, Alkynes, and Diaziridinone
The three-component reaction of aryl iodides, alkynes, and diaziridinone is described. The reaction provides an innovative synthetic approach for indoles. The approach features high efficiency, broad substrate scope, and excellent regioselectivity. C,C-Pa
Zhou, Bo,Wu, Zhuo,Ma, Ding,Ji, Xiaoming,Zhang, Yanghui
supporting information
p. 6440 - 6443
(2018/10/20)

Coupling of N -Nosylhydrazones with Nitrosoarenes: Transition-Metal-Free Approach to (Z)- N -Arylnitrones
An efficient and transition-metal-free protocol for the synthesis of (Z)- N -arylnitrones from the direct coupling of N -nosylhydrazones with nitrosoarenes under mild conditions is described. The protocol is compatible with a wide range of functional groups placed on both the reagents and provided the corresponding nitrones in good to excellent yields by simple recrystallization process. The use of these 1,3-dipoles for the synthesis of substituted indoles is elaborated for 2,3-diphenyl-1 H -indole.
Liu, Tingting,Liu, Zhaohong,Liu, Zhenhua,Hu, Donghua,Wang, Yeming
p. 1728 - 1736
(2018/02/14)

Biphilic Organophosphorus-Catalyzed Intramolecular Csp2-H Amination: Evidence for a Nitrenoid in Catalytic Cadogan Cyclizations
A small-ring phosphacycloalkane (1,2,2,3,4,4-hexamethylphosphetane, 3) catalyzes intramolecular C-N bond forming heterocyclization of o-nitrobiaryl and -styrenyl derivatives in the presence of a hydrosilane terminal reductant. The method provides scalable access to diverse carbazole and indole compounds under operationally trivial homogeneous organocatalytic conditions, as demonstrated by 17 examples conducted on 1 g scale. In situ NMR reaction monitoring studies support a mechanism involving catalytic PIII/PV=O cycling, where tricoordinate phosphorus compound 3 represents the catalytic resting state. For the catalytic conversion of o-nitrobiphenyl to carbazole, the kinetic reaction order was determined for phosphetane catalyst 3 (first order), substrate (first order), and phenylsilane (zeroth order). For differentially 5-substituted 2-nitrobiphenyls, the transformation is accelerated by electron-withdrawing substituents (Hammett factor ? = +1.5), consistent with the accrual of negative charge on the nitro substrate in the rate-determining step. DFT modeling of the turnover-limiting deoxygenation event implicates a rate-determining (3 + 1) cheletropic addition between the phosphetane catalyst 3 and 2-nitrobiphenyl substrate to form an unobserved pentacoordinate spiro-bicyclic dioxazaphosphetane, which decomposes via (2 + 2) cycloreversion giving 1 equiv of phosphetane P-oxide 3·[O] and 2-nitrosobiphenyl. Experimental and computational investigations into the C-N bond forming event suggest the involvement of an oxazaphosphirane (2 + 1) adduct between 3 and 2-nitrosobiphenyl, which evolves through loss of phosphetane P-oxide 3·[O] to give the observed carbazole product via C-H insertion in a nitrene-like fashion.
Nykaza, Trevor V.,Ramirez, Antonio,Harrison, Tyler S.,Luzung, Michael R.,Radosevich, Alexander T.
supporting information
p. 3103 - 3113
(2018/03/08)

Method for preparing indole compounds by using rhodium/carbon as catalyst
The invention provides a method for preparing indole compounds by using rhodium/carbon as a catalyst. Corresponding indole compounds are formed through subjecting aniline and analogs thereof and alkyne to a catalytic cyclization reaction in the presence of the rhodium/carbon. The method has the beneficial effects that the preparation method is simple in process, the raw materials are cheap and readily available, the yield is high, inert-gas protection is not required, and the reaction temperature is relatively moderate.
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Paragraph 0029-0031; 0034; 0036

(2018/04/26)

A palladium/carbon as catalyst preparation of indole compounds method (by machine translation)
The present invention provides a palladium/carbon as catalyst preparation of indole compounds method, aniline and its analogs in the palladium/carbon with the alkyne under the action of the catalytic cyclization reaction, to form the corresponding indoles. This method has the advantages of: simple preparation method, the raw material is cheap, high yield, without protection of inert gas, the reaction temperature is relatively mild. (by machine translation)
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Paragraph 0029; 0030; 0031; 0033

(2018/06/15)

Catalytic Asymmetric N-Alkylation of Indoles and Carbazoles through 1,6-Conjugate Addition of Aza-para-quinone Methides
Catalytic asymmetric N-alkylation of indoles and carbazoles represents a family of important but underdeveloped reactions. Herein, we describe a new organocatalytic strategy in which in situ generated aza-para-quinone methides are employed as the alkylating reagent. With the proper choice of a chiral phosphoric acid and an N-protective group, the intermolecular C?N bond formation with various indole and carbazole nucleophiles proceeded efficiently under mild conditions with excellent enantioselectivity and functional-group compatibility. Control experiments and kinetic studies provided important insight into the reaction mechanism.
Chen, Min,Sun, Jianwei
supporting information
p. 4583 - 4587
(2017/04/11)

Transition-metal-free, visible-light-mediated cyclization of: O -azidoarylalkynes with aryl diazonium salts
Visible light along with 3 mol% eosin Y catalyzes the cyclization reaction of o-azidoarylalkynes with aryl diazonium salts by a photoredox process. We have investigated the scope of the reaction for several aryl diazonium salts and o-azidoarylalkynes. The general and easy procedure provides a transition-metal-free alternative for the formation of unsymmetrical 2,3-diaryl-substitued indoles.
Jin, Cheng,Su, Lianzheng,Ma, Daxi,Cheng, Mingrong
supporting information
p. 14053 - 14056
(2017/11/28)

Transition-metal-free, visible-light induced cyclization of arylsulfonyl chlorides with o-azidoarylalkynes: a regiospecific route to unsymmetrical 2,3-disubstituted indoles
A visible-light-catalyzed synthesis of unsymmetrical 2,3-diaryl-substituted indoles from arylsulfonyl chlorides and o-azidoarylalkynes at room temperature has been discovered. This transformation exhibits excellent substrate scope and functional group tolerance. The use of inexpensive eosin Y as the catalyst with easy operation makes this protocol very practical.
Gu, Lijun,Jin, Cheng,Wang, Wei,He, Yonghui,Yang, Guangyu,Li, Ganpeng
supporting information
p. 4203 - 4206
(2017/04/21)

Mechanochemical indole synthesis by rhodium-catalysed oxidative coupling of acetanilides and alkynes under solventless conditions in a ball mill
A mechanochemical indole synthesis by rhodium(iii)-catalysed C-H bond functionalisation in a planetary mill has been developed. It occurs in the absence of any solvent, does not require additional heating and only needs catalytic quantities of Cu(OAc)2 in combination with dioxygen as a terminal oxidant. Accordingly, the process represents a powerful and environmentally benign alternative to the common solution-based standard protocols.
Hermann, Gary N.,Jung, Celine L.,Bolm, Carsten
supporting information
p. 2520 - 2523
(2017/07/17)

A synthetic 2,3-diarylindole induces cell death via apoptosis and autophagy in A549 lung cancer cells
A series of 2,3-diarylindoles were synthesized via the Larock heteroannulation, and evaluated for their anticancer activity against A549 lung cancer cells. The most potent compound, PCNT13 with IC50 = 5.17 μM, caused the induction of two modes of programmed cell death, apoptosis and autophagy.
Rukkijakan, Thanya,Ngiwsara, Lukana,Lirdprapamongkol, Kriengsak,Svasti, Jisnuson,Phetrak, Nared,Chuawong, Pitak
p. 2119 - 2123
(2016/04/20)

Catalytic synthesis method of indole compounds
The invention discloses a catalytic synthesis method of indole compounds.The method includes the following steps of firstly, conducting stirring reaction on ortho-nitrostyrolene or derivatives of ortho-nitrostyrolene, bis(pinacolato)diboron, alkali and low-grade saturated monohydric alcohol under the atmosphere of nitrogen; secondly, cooling the reaction product in the first step to the room temperature, adding ethyl acetate to be sufficiently mixed, and washing with ethyl acetate after filtering; thirdly, spin-drying low-grade saturated monohydric alcohol in an organic phase of the material obtained in the second step, passing through a silica gel column, and drip washing the silica gel column with eluent composed of petroleum ether and ethyl acetate to obtain pure products, namely, the indole compounds.By means of the method, under the neutral conditions, bis(pinacolato)diboron low in price serves as the raw material, friendly low-grade saturated monohydric alcohol serves as the solvent, the indole compounds are obtained through simple operation, the raw materials are low in price and easy to obtain, efficiency and safety are high, and wide expandability and good industrial application prospects are achieved.
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Paragraph 0032; 0033; 0034; 0035

(2016/10/10)

Palladium-catalyzed direct arylation of indoles with arylsulfonyl hydrazides
A novel method to synthesise 2-arylindoles is demonstrated via direct arylation of indoles with arylsulfonyl hydrazides. Under the optimized reaction conditions, the reaction well tolerates a wide variety of functional groups to afford structurally diverse 2-arylindoles in good to excellent yields at 70 °C.
Liu, Congrong,Ding, Lianghui,Guo, Guang,Liu, Weiwei,Yang, Fu-Lai
p. 2824 - 2827
(2016/03/12)

Indole Synthesis through Sequential Electrophilic N-H and C-H Bond Activation Using Iodine(III) Reactivity
An intramolecular approach towards the regioselective construction of 2,3-diarylated indoles is reported. The reaction follows an intramolecular electrophilic N-H and C-H bond functionalization between the aniline and acetylene. This methodology employs the concept of a traceless tether to provide access to the free 2,3-diarylated indole products comprising a total of 18 examples. Hypervalent iodine reagents were identified as suitable promoters and four different protocols are provided, including stoichiometric and catalytic transformations.
Fra, Laura,Mu?iz, Kilian
p. 4351 - 4354
(2016/03/22)

Selective Synthesis of N-Unsubstituted and N-Arylindoles by the Reaction of Arynes with Azirines
The transition-metal-free and temperature-dependent highly selective reaction of arynes with 2H-azirines allowing the synthesis of either N-unsubstituted or N-arylindoles has been developed. At 60 °C, arynes generated from 2-(trimethylsilyl)aryl triflates smoothly insert into 2H-azirines to form 2,3-diarylindoles with high selectivity. Interestingly, when the reaction was performed at -10 °C, the selectivity was switched to the formation of 1,2,3-triarylindoles in good yields.
Thangaraj, Manikandan,Bhojgude, Sachin Suresh,Jain, Shailja,Gonnade, Rajesh G.,Biju, Akkattu T.
p. 8604 - 8611
(2016/09/28)

Cobalt(III)-Catalyzed Redox-Neutral Synthesis of Unprotected Indoles Featuring an N-N Bond Cleavage
A redox-neutral cobalt(III)-catalyzed synthetic approach for the direct synthesis of unprotected indoles showcasing an N-N bond cleavage is reported. The herein newly introduced Boc-protected hydrazines establish a beneficial addition to the limited portfolio of oxidizing directing groups for cobalt(III) catalysis. Moreover, the developed catalytic methodology tolerates a good variety of functional groups.
Lerchen, Andreas,Vásquez-Céspedes, Suhelen,Glorius, Frank
supporting information
p. 3208 - 3211
(2016/03/12)

Selective Synthesis of Indoles by Cobalt(III)-Catalyzed C-H/N-O Functionalization with Nitrones
The redox-neutral annulation of alkynes by differently decorated nitrones set the stage for a step-economical access to indoles with ample substrate scope. The redox-neutral C-H/N-O functionalization process proceeded through kinetically relevant C-H activation by carboxylate assistance, and displayed an excellent site- and regio-selectivity with unsymmetrical nitrones and alkynes.
Wang, Hui,Moselage, Marc,González, María J.,Ackermann, Lutz
p. 2705 - 2709
(2016/04/26)

A kind of high-efficient synthetic indole and isoquinoline derivatives (by machine translation)
The invention discloses a substituted indole and isoquinoline preparation method, which belongs to the technical field of organic chemical synthesis. This method adopts the oxygen as the oxidizing agent, various substituents substituted alkyne starting material of the aromatic amine or [...] , by transition metal-catalyzed, get containing indole or isoquinoline compound of the structure. The reaction raw material, oxidizing agent and cheap and easily obtained catalyst, synthesis technique is simple, which greatly reduces the cost of synthesizing; mild reaction conditions, high yield, easy industrialization; reaction raw materials and catalyst cleaning non-toxic, small pollution to the environment. Such compounds and their derivatives as an important fine chemicals, in the medical, agricultural chemicals, perfume and widely used photoelectric and other industries. (by machine translation)
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Paragraph 0021; 0022; 0026

(2016/10/07)

URAZOLE COMPOUNDS
The present invention relates to a compound of formula (I) or a stereoisomer, enantiomer, racemic, or tautomer thereof, (I) wherein R1, R2, R3, R4, R5, R6, R7, L1 and Q1 have the meaning defined in the claims and the description. The present invention also relates to a process for the preparation of the compound of formula (I). The present invention also relates to the use of a compound of formula (I) as an in situ precursor of a triazolinedione reagent for the functionalization of enes, dienes, aryl and heteroaryl systems via the ene reactions, Diels-Alder reactions, and electrophilic aromatic substitution reactions of said reagent. The present invention also relates to the use of a compound of formula (I) in polymers, membranes, adhesives, foams, sealants, molded articles, films, extruded articles, fibers, elastomers, polymer based additives, pharmaceutical and biomedical products, varnishes, paints, coatings, inks, composite material, organic LEDs, organic semiconductors, conducting organic polymers, or 3D printed articles. The present invention also relates to article comprising said compound of formula (I) and to a process for reshaping and/or repairing said article.
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Page/Page column 177

(2015/02/25)

A Convenient Modification of the Fischer Indole Synthesis with a Solid Acid
(Chemical Equation Presented). A new one-pot version of the titled reaction involves heating a mixture of a carbonyl compound, a phenylhydrazine, and the cation exchange resin Amberlite IR 120 in refluxing ethanol. A variety of enolizable aldehydes, and ketones and several substituted phenylhydrazines could thus be converted to the corresponding indoles in excellent yields (70-88%). Reaction times were typically 6-10 h, with the resin being then filtered off and the product isolated after minimal workup.
Chandrasekhar, Sosale,Mukherjee, Somnath
supporting information
p. 1018 - 1022
(2015/03/30)

Rhodium-Catalyzed C-H Annulation of Nitrones with Alkynes: A Regiospecific Route to Unsymmetrical 2,3-Diaryl-Substituted Indoles
The direct C-H annulation of anilines or related compounds with internal alkynes provides straightforward access to 2,3-disubstituted indole products. However, this transformation proceeds with poor regioselectivity in the synthesis of unsymmetrically 2,3-diaryl substituted indoles. Herein, we report the rhodium(III)-catalyzed C-H annulation of nitrones with symmetrical diaryl alkynes as an alternative method to prepare 2,3-diaryl-substituted N-unprotected indoles with two different aryl groups. One of the aryl substituents is derived from N?C-aryl ring of the nitrone and the other from the alkyne substrate, thus providing the indole products with exclusive regioselectivity.
Yan, Hao,Wang, Haolong,Li, Xincheng,Xin, Xiaoyi,Wang, Chunxiang,Wan, Boshun
p. 10613 - 10617
(2015/09/02)

Palladium-Catalyzed Formation of N-Heteroarenes from Nitroarenes using Molybdenum Hexacarbonyl as the Source of Carbon Monoxide
The development of a method that employs a two-chamber reaction vessel and uses molybdenum hexacarbonyl [Mo(CO)6] as the carbon monoxide (CO) source for the palladium-catalyzed transformation of nitroarenes into indoles or imidazoles is reported.
Zhou, Fei,Wang, Duo-Sheng,Driver, Tom G.
p. 3463 - 3468
(2016/01/25)

Rhodium(III)-Catalyzed Redox-Neutral C-H Annulation of Arylnitrones and Alkynes for the Synthesis of Indole Derivatives
By using a nitrone as the oxidizing directing group, a mild, practical and efficient rhodium(III)-catalyzed C-H functionalization for the synthesis of indole derivatives has been developed. This reaction obviates the need for an external oxidant and shows good functional group tolerance. The employment of a sterically hindered Mes group on the carbon center of the nitrone is crucial to produce indoles in high yield.
Zhou, Zhi,Liu, Guixia,Chen, Yan,Lu, Xiyan
supporting information
p. 2944 - 2950
(2015/09/28)

RhIII-catalyzed redox-neutral C-H activation of pyrazolones: An economical approach for the synthesis of N-substituted indoles
A new strategy is reported for the economical synthesis of indoles bearing an N-(3-aminobut-2-enoyl) substituent through RhIII-catalyzed redox-neutral C-H activation of pyrazolones and alkynes. This approach utilizes cheap substrates and mild reaction conditions to access a unique class of indoles via a N-N bond oxidative cleavage without loss of the N-terminus, therefore meeting all the atom/step/redox economy principles.
Fan, Zhoulong,Song, Shanshan,Li, Wei,Geng, Kaijun,Xu, Youjun,Miao, Ze-Hong,Zhang, Ao
supporting information
p. 310 - 313
(2015/01/30)

Polystyrene supported thiopseudourea Pd(II) complex: Applications for Sonogashira, Suzuki-Miyaura, Heck, Hiyama and Larock heteroannulation reactions
A new polystyrene supported thiopseudourea palladium(II) complex (3) is found to be a highly active catalyst for the copper-free Sonogashira, Suzuki, Heck, Hiyama and Larock heteroannulation reactions of aryl halides. All the reactions proceeded well affording the corresponding cross-coupling products in good to excellent yields. Further, the catalyst showed excellent recyclability without any significant loss in its activity.
Keesara, Srinivas,Parvathaneni, Saiprathima,Dussa, Govardhan,Mandapati, Mohan Rao
p. 31 - 38
(2014/06/09)