- Iodine-Catalyzed Aerobic Diazenylation-Amination of Indole Derivatives
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A mild strategy for consecutive diazenylation and amination of indole moieties has been demonstrated. The functionalization occurs at C3 and C2 carbon atoms, respectively, at the indole scaffold in the presence of catalytic iodine and air at 40 °C in the 1,1,1,3,3,3-hexafluoroisopropanol (HFIP) solvent. It is noteworthy that the aromatic amines are generated in situ by the reaction of aryl hydrazine with iodine. In general, bright red products are obtained in moderate to good yield. Control reactions are conducted to establish the reaction mechanism.
- Sar, Saibal,Tripathi, Ankita,Dubey, Kshatresh Dutta,Sen, Subhabrata
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- Covalent Organic Frameworks toward Diverse Photocatalytic Aerobic Oxidations
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Photoactive two-dimensional covalent organic frameworks (2D-COFs) have become promising heterogenous photocatalysts in visible-light-driven organic transformations. Herein, a visible-light-driven selective aerobic oxidation of various small organic molecules by using 2D-COFs as the photocatalyst was developed. In this protocol, due to the remarkable photocatalytic capability of hydrazone-based 2D-COF-1 on molecular oxygen activation, a wide range of amides, quinolones, heterocyclic compounds, and sulfoxides were obtained with high efficiency and excellent functional group tolerance under very mild reaction conditions. Furthermore, benefiting from the inherent advantage of heterogenous photocatalysis, prominent sustainability and easy photocatalyst recyclability, a drug molecule (modafinil) and an oxidized mustard gas simulant (2-chloroethyl ethyl sulfoxide) were selectively and easily obtained in scale-up reactions. Mechanistic investigations were conducted using radical quenching experiments and in situ ESR spectroscopy, all corroborating the proposed role of 2D-COF-1 in photocatalytic cycle.
- Liu, Shuyang,Tian, Miao,Bu, Xiubin,Tian, Hua,Yang, Xiaobo
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supporting information
p. 7738 - 7744
(2021/05/07)
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- Manganese(III) Acetate Catalyzed Aerobic Dehydrogenation of Tertiary Indolines, Tetrahydroquinolines and an N-Unsubstituted Indoline
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A Mn(OAc)3 ? 2H2O-catalyzed aerobic dehydrogenation of five and six-membered N-heterocycles for the synthesis of N-heteroarenes is reported. Of note, this protocol can be applied to the dehydrogenation of tertiary indolines with various electron-deficient N-substituents. Preliminary mechanistic investigations support that a single-electron transfer pathway might be involved. (Figure presented.).
- Niu, Xiaokang,Yang, Lei
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supporting information
p. 4209 - 4215
(2021/08/06)
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- Synthesis of 3-halogenated 2,3′-biindoles by a copper-mediated 2,3-difunctionalization of indoles
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A copper-mediated 2,3-difunctionalization of indoles to afford 3-halogenated 2,3′-biindoles is described herein. The protocol uses readily available feedstocks and a naturally abundant copper catalyst system, which allows the regioselective formation of C-C and C-X (X = Cl & Br) bonds in one single operation. Here the copper metal salt serves not only as a catalyst but also as a reactant to provide the source of halogen. This operationally simple procedure avoids the utilization of environmentally unfriendly reagents and displays good functional group compatibility. Noteworthily, the introduction of halogen into molecules would offer great potential for further chemical transformations. This journal is
- Gu, Xiaoting,Liang, Taoyuan,Wei, Wanxing,Zhang, Xiaoxiang,Zhang, Yingying,Zhang, Zhuan
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supporting information
p. 10403 - 10407
(2021/12/17)
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- Metal-Free C?H Borylation of N-Heteroarenes by Boron Trifluoride
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Organoboron compounds are essential reagents in modern C?C coupling reactions. Their synthesis via catalytic C?H borylation by main group elements is emerging as a powerful tool alternative to transition metal based catalysis. Herein, a straightforward metal-free synthesis of aryldifluoroboranes from BF3 and heteroarenes is reported. The reaction is assisted by sterically hindered amines and catalytic amounts of thioureas. According to computational studies the reaction proceeds via frustrated Lewis pair (FLP) mechanism. The obtained aryldifluoroboranes are further stabilized against destructive protodeborylation by converting them to the corresponding air stable tetramethylammonium organotrifluoroborates.
- Iashin, Vladimir,Berta, Dénes,Chernichenko, Konstantin,Nieger, Martin,Moslova, Karina,Pápai, Imre,Repo, Timo
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supporting information
p. 13873 - 13879
(2020/10/02)
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- Sulfoxide-Promoted Chlorination of Indoles and Electron-Rich Arenes with Chlorine as Nucleophile
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An efficient chlorination of indoles and electron-rich arenes with chlorine anion as nucleophile is described. With the use of ethyl phenyl sulfoxide as the promoter, the reaction went smoothly under metal-free and mild conditions. Various indoles and electron-rich arenes are converted into the corresponding chlorinated compounds in moderate to excellent yields. A plausible interrupted Pummerer reaction mechanism was proposed without the oxidation of chloride anion. In addition, the byproduct thioether could be easily converted to the starting material sulfoxide just by a simple oxidation reaction. (Figure presented.).
- Ji, Yuan-Zhao,Li, Hui-Jing,Wang, Yi-Ruo,Wu, Yan-Chao,Zhang, Zheng-Yan
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supporting information
(2020/02/05)
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- Synthesis of Cyclopenta[b]indoles via a Formal [3+2] Cyclization of N-Sulfonyl-1,2,3-triazoles and Indoles
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Annulation of benzoxy-tethered N-sulfonyl-1,2,3-triazoles and indoles has been developed in this paper, providing an efficient and convenient access to valuable cyclopenta[b]indoles in moderate to good yields. α,β-Unsaturated imine, which generated in situ from denitrogenation and 1,2-OBz migration of triazole, provided three carbons for the formal [3+2] cyclization reaction for the first time. (Figure presented.).
- Duan, Shengguo,Zhang, Wan,Hu, Yuntong,Xu, Ze-Feng,Li, Chuan-Ying
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supporting information
p. 3570 - 3575
(2020/08/05)
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- Enantioselective Construction of Si-Stereogenic Center via Rhodium-Catalyzed Intermolecular Hydrosilylation of Alkene
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Catalytic, enantioselective synthesis of stereogenic silicon compounds remains a challenge. Herein, we report a rhodium-catalyzed regio- and enantio-selective intermolecular hydrosilylation of alkene with prochiral dihydrosilane. This new method features a simple catalytic system, mild reaction conditions and a wide functional group tolerance.
- He, Tao,Liu, Li-Chuan,Ma, Wen-Peng,Li, Bin,Zhang, Qing-Wei,He, Wei
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supporting information
p. 17011 - 17015
(2020/11/30)
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- Cobalt-Catalyzed Cycloamination: Synthesis and Photophysical Properties of Polycyclic N-Heterocycles
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The first earth-abundant cobalt-catalyzed cycloamination of indolylquinones and various (hetero)aromatic amine under ligand-free conditions for the synthesis of polycyclic N-heterocycles has been developed. The process allows facile access to polycyclic N-heterocycles with tolerance of chloride, bromide, amino, thio, etc. groups in moderate to high yields (up to 89percent). In addition, The photophysical properties of the synthesized products were evaluated. These products exhibit interesting fluorescence properties, which is promising for fluorescent probes.
- Dong, Yu,He, Shuai,Shi, Zhi-Chuan,Wang, Ji-Yu,Yang, Jian,Zhan, Xiao-Yu,Zhang, Hua,Zhang, Xiao-Mei
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supporting information
(2020/07/15)
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- γ-Carboline synthesis enabled by Rh(iii)-catalysed regioselective C-H annulation
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A redox-neutral Rh(iii)-catalyzed C-H annulation of indolyl oximes was developed. Relying on the use of various alkynyl silanes as the terminal alkyne surrogates, the reaction exhibited a reverse regioselectivity, thus giving an exclusive and easy way for the synthesis of a wide range of substituent free γ-carbolines at C3 position with high efficiency. Deuterium-labelling experiments and kinetic analysis have preliminarily shed light on the working mode of this catalytic system. This journal is
- Jiang, Bo,Jia, Jingwen,Sun, Yufei,Wang, Yichun,Zeng, Jing,Bu, Xiubin,Shi, Liangliang,Sun, Xiaoying,Yang, Xiaobo
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supporting information
p. 13389 - 13392
(2020/11/10)
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- Straightforward access to novel indolo[2,3-: B] indoles via aerobic copper-catalyzed [3+2] annulation of diarylamines and indoles
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Herein, we report an unprecedented aerobic copper-catalyzed [3+2] annulation reaction of diarylamines with indoles, which allows direct access to novel 2-diarylaminoindolo[2,3-b]indoles, a class of potential photoelectric device molecules. The developed transformation proceeds with broad substrate scope, good functional group tolerance, high chemo-selectivity, and no need for pre-preparation of specific agents, which offers a practical route for diverse and atom-economic synthesis of the desired products that are difficult to prepare with the conventional approaches.
- Gong, Lingzhen,Jiang, Huanfeng,Liang, Taoyuan,Zhang, Min,Zhao, He
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supporting information
p. 2807 - 2810
(2020/03/13)
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- A rhodium(ii) catalysed domino synthesis of azepino fused diindoles from isatin tethered: N -sulfonyl-1,2,3-triazoles and indoles
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An efficient and convenient protocol for the synthesis of a novel class of azepino fused diindoles from isatin tethered N-sulfonyl-1,2,3-triazoles and indoles has been disclosed. The reaction proceeds via denitrogenative aza-vinyl rhodium carbene formation to give a carbonyl ylide, which with indole results in 1,3-dipolar cycloaddition followed by sequential semipinacol rearrangement/ring expansion/oxidation to produce azepino fused diindoles. The reaction shows a broad substrate scope giving up to 81% yield. Furthermore, reversible catalytic hydrogenation and photophysical studies were carried out to demonstrate the application of these molecules.
- Kahar, Nilesh,Jadhav, Pankaj,Reddy, R. V. Ramana,Dawande, Sudam
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supporting information
p. 1207 - 1210
(2020/02/04)
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- Catalytic Tandem Friedel-Crafts Alkylation/C4-C3 Ring-Contraction Reaction: An Efficient Route for the Synthesis of Indolyl Cyclopropanecarbaldehydes and Ketones
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A general strategy for the synthesis of indolyl cyclopropanecarbaldehydes and ketones via a Br?nsted acid-catalyzed indole nucleophilic addition/ring-contraction reaction sequence has been exploited. The procedure leads to a wide panel of cyclopropyl carbonyl compounds in generally high yields with a broad substrate scope.
- Turnu, Francesca,Luridiana, Alberto,Cocco, Andrea,Porcu, Stefania,Frongia, Angelo,Sarais, Giorgia,Secci, Francesco
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supporting information
p. 7329 - 7332
(2019/10/02)
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- Isodesmic C-H Borylation: Perspectives and Proof of Concept of Transfer Borylation Catalysis
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The potential advantages of using arylboronic esters as boron sources in C-H borylation are discussed. The concept is showcased using commercially available 2-mercaptopyridine as a metal-free catalyst for the transfer borylation of heteroarenes using arylboronates as borylation agents. The catalysis shows a unique functional group tolerance among C-H borylation reactions, tolerating notably terminal alkene and alkyne functional groups. The mechanistic investigation is also described.
- Rochette, étienne,Desrosiers, Vincent,Soltani, Yashar,Fontaine, Frédéric-Georges
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supporting information
p. 12305 - 12311
(2019/08/20)
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- Tryptamine Synthesis by Iron Porphyrin Catalyzed C?H Functionalization of Indoles with Diazoacetonitrile
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The functionalization of C?H bonds with non-precious metal catalysts is an important research area for the development of efficient and sustainable processes. Herein, we describe the development of iron porphyrin catalyzed reactions of diazoacetonitrile with N-heterocycles yielding important precursors of tryptamines, along with experimental mechanistic studies and proof-of-concept studies of an enzymatic process with YfeX enzyme. By using readily available FeTPPCl, we achieved the highly efficient C?H functionalization of indole and indazole heterocycles. These transformations feature mild reaction conditions, excellent yields with broad functional group tolerance, can be conducted on gram scale, and thus provide a unique streamlined access to tryptamines.
- Hock, Katharina J.,Knorrscheidt, Anja,Hommelsheim, Renè,Ho, Junming,Weissenborn, Martin J.,Koenigs, Rene M.
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supporting information
p. 3630 - 3634
(2019/02/13)
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- Electrochemically Enabled C3-Formylation and -Acylation of Indoles with Aldehydes
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Reported herein is an effective strategy for oxidative cross-coupling of indoles with various aldehydes. The strategy is based on a two-step transformation via a well-known Mannich-type reaction and a C-N bond cleavage for carbonyl introduction. The key step - the C-N bond cleavage of the Mannich product - was enabled by electrochemistry. This strategy (with over 40 examples) ensures excellent functional-group tolerance as well as late-stage functionalization of pharmaceutical molecules.
- Yang, Liquan,Liu, Zhaoran,Li, Yujun,Lei, Ning,Shen, Yanling,Zheng, Ke
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supporting information
p. 7702 - 7707
(2019/10/19)
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- Electrochemical Regioselective Bromination of Electron-Rich Aromatic Rings Using n Bu 4 NBr
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Electrochemical regioselective bromination of electron-rich aromatic rings using stoichiometric tetrabutylammonium bromide (n Bu 4 NBr) has been accomplished under mild conditions. This protocol provides an environmentally friendly and simple way for the construction of C-Br bond in moderate to high yields with wide functional group tolerance.
- Bai, Ya,Che, Xin,Liu, Nian,Ning, Shulin,Shi, Lingling,Wang, Shutao,Wang, Siyu,Xiang, Jinbao,Xie, Wenxia
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p. 1313 - 1316
(2019/06/20)
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- Palladium-catalyzed N1-selective allylation of indoles with allylic alcohols promoted by titanium tetraisopropoxide
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The direct N1-selective allylation of indoles with allylic alcohols has been accomplished by synergistic functions of palladium catalysts and titanium tetraisopropoxide. The site selectivity is notably different from that observed in other related transition metal-catalyzed approaches. This chemistry provides a facile route to a variety of allylated indoles in synthetically useful yields. The utility of this simple allylation reaction was demonstrated with the first total synthesis of (+)-N-(4′-hydroxyprenyl)-cyclo(alanyltryptophyl), which was completed in five steps, starting from l-tryptophan methyl ester hydrochloride.
- Chang, Chieh-Yu,Lin, Yu-Huan,Wu, Yen-Ku
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supporting information
p. 1116 - 1119
(2019/01/29)
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- Replacement of Stoichiometric DDQ with a Low Potential o-Quinone Catalyst Enabling Aerobic Dehydrogenation of Tertiary Indolines in Pharmaceutical Intermediates
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A transition-metal/quinone complex, [Ru(phd)3]2+ (phd = 1,10-phenanthroline-5,6-dione), is shown to be effective for aerobic dehydrogenation of 3° indolines to the corresponding indoles. The results show how low potential quinones may be tailored to provide a catalytic alternative to stoichiometric DDQ, due to their ability to mediate efficient substrate dehydrogenation while also being compatible with facile reoxidation by O2. The utility of the method is demonstrated in the synthesis of key intermediates to pharmaceutically important molecules.
- Li, Bao,Wendlandt, Alison E.,Stahl, Shannon S.
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supporting information
p. 1176 - 1181
(2019/02/14)
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- Tandem Rh(II) and Chiral Squaramide Relay Catalysis: Enantioselective Synthesis of Dihydro-β-carbolines via Insertion to C-H Bond and Aza-Michael Reaction
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An efficient tandem rhodium(II)/squaramide relay catalysis of readily accessible indole derivatives and N-sulfonyl-1,2,3-triazoles has been developed for the enantioselective synthesis of dihydro-β-carbolines in good yield and enantioselectivity. The developed reaction involves selective insertion of in situ generated azavinyl rhodium carbene onto the C3-H bond of indole derivatives and subsequent squaramide-catalyzed enantioselective intramolecular aza-Michael reaction. Furthermore, the potential of the strategy was demonstrated through the ready conversion to potent tetrahydro-β-carbolines and the tetracyclic alkaloid core structure.
- Rajasekar, Shanmugam,Anbarasan, Pazhamalai
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supporting information
p. 3067 - 3071
(2019/05/10)
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- Diastereoselective Allylation of Aldehydes by Dual Photoredox and Chromium Catalysis
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Herein, we report the redox-neutral allylation of aldehydes with readily available electron-rich allyl (hetero-) arenes, β-alkyl styrenes and allyl-diarylamines. This process was enabled by the combination of photoredox and chromium catalysis, which allowed a range of homoallylic alcohols to be prepared with high levels of selectivity for the anti diastereomer. Mechanistic investigations support the formation of an allyl chromium intermediate from allylic C(sp3)-H bonds and thus significantly extends the scope of the venerable Nozaki-Hiyama-Kishi reaction.
- Schwarz, J. Luca,Sch?fers, Felix,Tlahuext-Aca, Adrian,Lückemeier, Lukas,Glorius, Frank
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supporting information
p. 12705 - 12709
(2018/10/09)
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- Directly Bridging Indoles to 3,3′-Bisindolylmethanes by Using Carboxylic Acids and Hydrosilanes under Mild Conditions
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A straightforward Lewis acid-promoted protocol for 3,3′-bisindolylmethanes (BIMs) synthesis by reductive alkylation of indoles at the C3 position with carboxylic acids in the presence of hydrosilane was developed for the first time. Instead of aldehydes, more readily available, stable, and easy-to-handle carboxylic acids have been employed as alternative alkylating agents. As an efficient organocatalyst, B(C6F5)3 enables the reductive alkylation of various substituted indole derivatives with carboxylic acids with up to 98 % yield at room temperature and under neat conditions. This metal-free strategy offers an alternative approach for the direct functionalization of indoles to BIMs with carboxylic acids and such protocol allows selective reduction of carboxylic acid to aldehyde in combination with C?C bond formation.
- Qiao, Chang,Liu, Xiao-Fang,Fu, Hong-Chen,Yang, Hao-Peng,Zhang, Zhi-Bo,He, Liang-Nian
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p. 2664 - 2670
(2018/09/14)
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- Expedited Synthesis of Matrine Analogues through an Oxidative Cascade Addition/Double-Cyclization Radical Process
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The addition of a nicotinate–xanthate derivative to N-allylindoles and N-allylpyrroles resulted in polycyclic heterocycle-fused pyridonaphthyridines through a tandem radical intermolecular/intramolecular oxidative addition reaction sequence that created three new C–C bonds and two new rings in a single event. Such polyheterocycles showcase the matrine alkaloid framework and are similar to indole–monoterpenoid natural products.
- Olguín-Uribe, Simón,Mijangos, Marco V.,Amador-Sánchez, Yoarhy A.,Sánchez-Carmona, Miguel A.,Miranda, Luis D.
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supporting information
p. 2481 - 2485
(2017/05/12)
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- Isocyanide-Induced Activation of Copper Sulfate: Direct Access to Functionalized Heteroarene Sulfonic Esters
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A novel and direct approach to alkyl/aryl heteroarene sulfonic esters using copper sulfate as the environmentally benign inorganic sulfonation reagent was first realized with the aid of isocyanide. A variety of heterocycles reacted to afford the corresponding sulfonic esters through C?H functionalization. In this transformation, the otherwise inert copper sulfate was unusually activated by an isocyanide and employed as the source of the sulfonic substituents in an unprecedented fashion. The findings suggest that an appropriate activator may liberate the chemical activities of some relatively inert inorganic salts for organic synthesis.
- Hong, Xiaohu,Tan, Qitao,Liu, Bingxin,Xu, Bin
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supporting information
p. 3961 - 3965
(2017/03/27)
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- Gold-catalyzed oxidative couplings of two indoles with one aryldiazo cyanide under oxidant-free conditions
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Gold-catalyzed oxidative couplings of two indoles and one α-cyano gold carbene to form bis(indolyl)methane derivatives are described. Two different indoles are compatible with these reactions to provide reasonable yields. A plausible mechanism is postulated to rationalize the experimental data including product distributions, D2O labeling, and the significant effects of gold catalysts and cyano groups.
- Singh, Rahulkumar Rajmani,Liu, Rai-Shung
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supporting information
p. 4593 - 4596
(2017/04/28)
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- Introducing tetramethylurea as a new methylene precursor: a microwave-assisted RuCl3-catalyzed cross dehydrogenative coupling approach to bis(indolyl)methanes
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Herein we report a microwave assisted Ru(iii)/TBHP-mediated reaction of indoles with tetramethylurea (TMU) synthesizing symmetrical as well as unsymmetrical bis(indolyl)methanes, where TMU acts as a methylenating agent. This is the first report where TMU is used as a methylene source. Moreover, the synthesis of unsymmetrical bis(indolyl)methanes by using a carbon precursor is also reported herein for the first time. Various substituted indoles are used for the reaction. The reaction is high yielding and takes a much shorter time to accomplish compared to the existing methods.
- Deb, Mohit L.,Borpatra, Paran J.,Saikia, Prakash J.,Baruah, Pranjal K.
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supporting information
p. 1435 - 1443
(2017/02/15)
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- Regioselective N-allylation and N-cinnamylation of indoles using CuI-exchanged hierarchical nanoporous material
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Regioselective N-allylation and N-cinnamylation of indoles are achieved using a novel catalyst of CuI-exchanged hierarchically architectured nanoporous material (MMZCuIY). The catalyst was characterized by electron microscopy and X-ray methods. Other advantages like functional tolerance, easy separation and reusability of the catalyst are also highlighted.
- Senthilkumar,Kumarraja
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supporting information
p. 86 - 89
(2015/08/24)
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- An efficient ultrasound-assisted synthesis of n-alkyl derivatives of carbazole, indole, and phenothiazine
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Heterocyclic compounds bearing an acidic hydrogen atom attached to nitrogen such as carbazole, indole, and phenothiazine can be efficiently alkylated in DMSO or N,N-DMF under ultrasonic irradiation in the presence of potassium hydroxide as a base. In almost all cases, a dramatic reduction of the reaction time results and a clear yield increase accompanied by an improved quality of the products occurs.
- Zhao, Sanhu,Kang, Jin,Du, Yuting,Kang, Jingyan,Zhao, Xiaoni,Xu, Yinfeng,Chen, Ruixi,Wang, Qianqian,Shi, Xitao
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supporting information
p. 683 - 689
(2014/06/10)
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- Acid-catalyzed acylation reaction via C-C bond cleavage: A facile and mechanistically defined approach to synthesize 3-acylindoles
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A facile acid-catalyzed acylation of indoles with 1,3-dione as an eco-friendly acylating agent was developed. This protocol combines C-C bond cleavage and heterocyclic C-H bond functionalization to form new C-C bonds. Based on the detailed mechanistic studies, a credible mechanistic pathway was proposed. This journal is
- Xing, Qi,Li, Pan,Lv, Hui,Lang, Rui,Xia, Chungu,Li, Fuwei
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supporting information
p. 12181 - 12184
(2014/12/11)
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- Trifluoromethanesulfonic acid-catalyzed solvent-free bisindolylation of trifluoromethyl ketones
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A trifluoromethanesulfonic acid-catalyzed solvent-free bisindolylation reaction of indoles with alkyl and aryl trifluoromethyl ketones has been developed. The trifluoromethyl-substituted bisindolylalkane derivatives were synthesized in moderate to excellent yields.
- Wang, Yi,Yuan,Xing, Chun-Hui,Lu, Long
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supporting information
p. 1045 - 1048
(2014/02/14)
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- Trifluoromethanesulfonic acid-catalyzed solvent-free bisindolylation of trifluoromethyl ketones
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A trifluoromethanesulfonic acid-catalyzed solvent-free bisindolylation reaction of indoles with alkyl and aryl trifluoromethyl ketones has been developed. The trifluoromethyl-substituted bisindolylalkane derivatives were synthesized in moderate to excellent yields.
- Wang, Yi,Yuan, Yu,Xing, Chun-Hui,Lu, Long
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supporting information
p. 1045 - 1048
(2015/02/19)
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- Pd-catalyzed direct coupling of indoles with carbon monoxide and alkynes: Selective synthesis of linear α,β-unsaturated ketones
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A new strategy is described for the direct coupling of indoles with CO and alkynes to generate α,β-unsaturated ketones. This procedure, employing Xantphos and Pd(CH3CN)4(BF4) 2, is attractive from both environmental and operational points of view and adds value to the method for the carbonylation of alkynes by using carbon nucleophiles and affording linear regioselectivity.
- Zeng, Fanlong,Alper, Howard
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supporting information
p. 2034 - 2037
(2013/06/04)
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- C2-selective direct alkynylation of indoles
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The first C2-selective alkynylation of indoles using the hypervalent iodine reagent triisopropylsilylethynyl-1,2-benziodoxol-3(1H)-one (TIPS-EBX) with Pd(II) as a catalyst is described. This convenient and robust method gives a single-step access to substituted alkynyl indoles with very high C2 selectivity. The reaction is orthogonal to classical Pd(0) cross-coupling reactions, as it is tolerant to bromide and iodide substituents. The used silyl protecting group can be easily removed to give terminal acetylenes.
- Tolnai, Gergely L.,Ganss, Stephanie,Brand, Jonathan P.,Waser, Jerome
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supporting information
p. 112 - 115
(2013/03/28)
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- Copper-promoted decarboxylative direct C3-acylation of N-substituted indoles with α-oxocarboxylic acids
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A novel and efficient Cu-promoted decarboxylative direct C3-acylation of N-substituted indoles with α-oxocarboxylic acids for the synthesis of 3-acylindoles was developed. The Royal Society of Chemistry.
- Yu, Lin,Li, Pinhua,Wang, Lei
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supporting information
p. 2368 - 2370
(2013/06/27)
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- A general method for palladium-catalyzed direct carbonylation of indole with alcohol and phenol
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A novel strategy involving a first oxidative iodination and subsequent Pd0-catalyzed carbonylation to yield indole-3-carboxylate has been developed. It showed perfect generality to indole, alcohol, and phenol. The current methodology could also be conveniently applied to the synthesis of biologically active tropisetron from simple indole and tropine.
- Lang, Rui,Shi, Lijun,Li, Dengfeng,Xia, Chungu,Li, Fuwei
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supporting information; experimental part
p. 4130 - 4133
(2012/10/07)
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- Palladium-catalyzed mono- and double-carbonylation of indoles with amines controllably leading to amides and α-ketoamides
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A novel and efficient double-carbonylation of indoles with primary or secondary amines to yield indole-3-α-ketoamides has been developed and bioactive molecules could be one-pot synthesized using the current methodology, which could also be selectively switched to mono-carbonylation to afford indole-3-amides only by a slight modification of reaction conditions.
- Xing, Qi,Shi, Lijun,Lang, Rui,Xia, Chungu,Li, Fuwei
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supporting information
p. 11023 - 11025
(2013/01/15)
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- Palladium-assisted regioselective C-H cyanation of heteroarenes using isonitrile as cyanide source
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A palladium-catalyzed regioselective C-H cyanation of heteroarenes was achieved using tert-butyl isocyanide as "CN" source, which provides a new and unique strategy for the preparation of (hetero)aryl nitriles. Indoles, pyrroles, and aromatic rings could be efficiently cyanated through C-H bond activation with high regioselectivity.
- Xu, Shuguang,Huang, Xiaomei,Hong, Xiaohu,Xu, Bin
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supporting information
p. 4614 - 4617
(2012/11/06)
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- Palladium-catalyzed direct and regioselective C-H bond functionalization/ oxidative acetoxylation of indoles
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The first general examples of palladium-catalyzed direct and selective oxidative C3-acetoxylation of indoles are presented. The mild reaction conditions (70 °C and with weak base, KOAc) in this indole C-H-acetoxylation are notable.
- Choy, Pui Ying,Lau, Chak Po,Kwong, Fuk Yee
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supporting information; experimental part
p. 80 - 84
(2011/03/22)
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- Regioselective Rh-catalyzed direct carbonylation of indoles to synthesize indole-3-carboxylates
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Rh-catalyzed C-H carbonylation of indoles under 1 atm of CO has been achieved. Various substituted indoles and indole with free N-H could be carboxylated with linear- and/or cyclic-alcohol to give the desired indole-3-carboxylates with up to 92% yield. A mechanism involving Rh III initiated C-H metallation is proposed.
- Lang, Rui,Wu, Junliang,Shi, Lijun,Xia, Chungu,Li, Fuwei
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supporting information; experimental part
p. 12553 - 12555
(2012/02/02)
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- Directed synthesis and immunoactive properties of (2-hydroxyethyl)ammonium salts of 1-R-indol-3-ylsulfanyl(sulfonyl)alkanecarboxylic acids
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A general method for the synthesis of 1-alkyl(allyl)(benzyl)-substituted (indol-3-yl)-sulfanylalkanecarboxylic acids and hexane-1,6-diyl(1,4- phenylenemethylene)bisindol-3-ylsulfanylalkanecarboxylic acids from the corresponding N-substituted indoles and bisindoles, thiourea, iodine, and halogencarboxylic acids was developed. The oxidation of substituted (indol-3-yl)sulfanylalkanecarboxylic acids for the first time afforded their analogs containing the sulfonyl group. New (2-hydroxyethyl)ammonium salts of 1-R-indol-3-ylsulfanyl(sulfonyl)-alkanecarboxylic acids, which are structural analogs of highly active immunomodulators of indacetamin and VILIM, were synthesized. Among the studied (2-hydroxyethyl)ammonium salts of 1-R-indol-3-ylsulfanylacetic and -sulfonylalkanecarboxylic acids, the compounds exhibiting high dose-dependent antiproliferative activity by the ability to affect the spontaneous and mitogen-stimulated splenocyte proliferation of mice in vitro were found.
- Mirskova,Levkovskaya,Kolesnikova,Perminova,Rudyakova,Adamovich
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experimental part
p. 2236 - 2246
(2011/08/05)
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- Single bifunctional ruthenium catalyst for one-pot cyclization and hydration giving functionalized indoles and benzofurans
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Chemical equation Presented Bifunctional is more than twice as fun! At low loading, catalyst 1 (see scheme) can form two important heterocycle classes, apparently by attack of XH on a vinylidene intermediate. Aza- and nitroindoles can be formed, and all N-protecting groups tested (alkyl, allyl, sulfonyl) were tolerated. The newly formed ring can be deuterated in one step, and for substrates with two terminal alkynes, cyclization can be followed by hydration, making this catalyst uniquely versatile.
- Nair, Reji N.,Lee, Paul J.,Rheingold, Arnold L.,Grotjahn, Douglas B.
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supporting information; experimental part
p. 7992 - 7995
(2010/09/18)
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- Alkylation of the ambident indole ion in ionic liquids
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Alkylation of the ambident indole anion in ionic liquids has been investigated. The reaction rate is greater in ionic liquids than in organic solvents. The polarity of certain ionic liquids has been determined to be located between methanol and acetonitrile. 2008 Springer Science+Business Media, Inc.
- Vavilina,Zicmanis,Drozdova,Mekss,Klavins
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p. 530 - 541
(2013/07/27)
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- Di-μ-hydroxy-bis(N,N,N′,N′-tetramethylenediamine)-copper(II) chloride [Cu(OH)·TMEDA]2Cl2: An efficient, practical catalyst for benzylation and allylation of amides
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An efficient protocol for the benzylation or allylation of amides using the corresponding benzyl or allyl chlorides as electrophiles under basic conditions with commercially available 5 mol % of [Cu(OH)TMEDA]2Cl2 as catalyst was developed. Under these conditions, unprotected amino acids were benzylated without any racemization.
- Kumaraswamy,Pitchaiah,Ramakrishna,Ramakrishna,Sadaiah
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p. 2013 - 2015
(2007/10/03)
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- GLUCOCORTICOID MIMETICS, METHODS OF MAKING THEM, PHARMACEUTICAL COMPOSITIONS, AND USES THEREOF
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Compounds of Formula (IA) and (IB) wherein R?1?, R?2?, R?3?, A, B, C, D, and E are as defined herein, or a tautomer, prodrug, solvate, or salt thereof; pharmaceutical compositions containing such compounds, and methods of modulating the glucocorticoid receptor function and methods of treating disease-states or conditions mediated by the glucocorticoid receptor function or characterized by inflammatory, allergic, or proliferative processes in a patient using these compounds.
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Page/Page column 168
(2008/06/13)
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- Synthesis of bisindolylmaleimides related to GF109203x and their efficient conversion to the bioactive indolocarbazoles
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From a structure-activity relationship perspective, the new indolocarbazoles 11 and 12 have been synthesized and evaluated biologically as novel Chk1 inhibitors. Compounds 11 and 12 were synthesized in high yield from indole via bisindolylmaleimides 18 and 24. The Royal Society of Chemistry 2006.
- Roy, Sudipta,Eastman, Alan,Gribble, Gordon W.
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p. 3228 - 3234
(2008/03/14)
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- Evaluation of alternative approaches for the synthesis of macrocyclic bisindolylmaleimides
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Approaches for the synthesis of macrocyclic bisindolylmaleimides, in which the indole nitrogens are linked with a tether, are described. Two alternative approaches were investigated: macrocyclisation in either the southern (by adding the tether to the bisindolylmaleimide ring system) or the northern district. With two-, three-and four-atom tethers, both of these approaches were unsuccessful for a wide range of attempted macrocyclisation reactions (palladium-catalysed π-allyl substitution, ring-closing metathesis, McMurry reaction, iodocyclisation, formation of a silylene derivative, substitution of an α,ω-disubstituted electrophile). The failure of all of these reactions was ascribed to the strained nature of the target ring system. However, with longer tethers (six to ten atoms), the macrocycles could prepared using either a ring-closing metathesis reaction or by substitution of an α,ω-dibromide). Fourteen successful macrocyclisation reactions are described; deprotection gave eleven macrocyclic bisindolylmaleimides in which an imide substituent had been removed.
- Bartlett, Stephen,Nelson, Adam
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p. 2874 - 2883
(2007/10/03)
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- Enantioselective indole Friedel-Crafts alkylations catalyzed by bis(oxazolinyl)pyridine-scandium(III) triflate complexes
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A highly enantioselective Friedel-Crafts alkylation of electron-rich aromatic nucleophiles catalyzed by scandium(III) triflate-pyridyl(bis)oxazoline complexes has been accomplished. The reaction involves α,β-unsaturated acyl phosphonates as electrophiles and primarily substituted indoles as nucleophiles. The reactive acyl phosphonate product is converted to the corresponding ester or amide in good overall yield by adding an alcohol or amine directly to the reaction mixture. Copyright
- Evans, David A.,Scheidt, Karl A.,Fandrick, Keith R.,Lam, Hon Wai,Wu, Jimmy
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p. 10780 - 10781
(2007/10/03)
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- Radical cyclisation reactions of 7-bromoindoles
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The synthesis and radical cyclisation of 7-bromoindoles carrying an unsaturated N-alkyl group is described.
- Dobbs, Adrian P.,Jones, Keith,Veal, Ken T.
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p. 5379 - 5382
(2007/10/03)
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- Remarkable fast n-alkylation of azaheterocycles under microwave irradiation in dry media
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Under microwave irradiation a number of azaheterocycles (i.e., pyrrole, imidazole, pyrazole, indole, and carbazole) react remarkably fast with alkyl halides to give exclusively N-alkyl derivatives.
- Bogdal, Dariusz,Pielichowski, Jan,Jaskot, Krzysztof
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p. 715 - 722
(2007/10/03)
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