- Picolinic acids as β-exosite inhibitors of botulinum neurotoxin A light chain
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In developing small-molecule inhibitors of botulinum neurotoxin serotype A light chain (BoNT/A LC), substituted picolinic acids were identified. Extensive investigation into the SAR of the picolinic acid scaffold revealed 5-(1-butyl-4-chloro-1H-indol-2-yl)picolinic acid (CBIP), which possessed low micromolar activity against BoNT/A. Kinetic and docking studies demonstrated binding of CBIP to the β-exosite: a largely unexplored site on the LC that holds therapeutic relevance for botulism treatment.
- Bremer, Paul T.,Xue, Song,Janda, Kim D.
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- THE TRANSITION METAL-CATALYZED N-HETEROCYCLIZATION. THE RHODIUM-CATALYZED SYNTHESIS OF INDOLES
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Substituted indoles can be prepared in high yields by the reaction between phenylhydrazine and carbonyl compounds at 180 deg C in the presence of a catalytic amount of a rhodium complex under non-acidic condition.
- Watanabe, Yoshihisa,Yamamoto, Michihiro,Shim, Sang Chul,Miyanaga, Sogo,Mitsudo, Take-aki
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- Horseradish peroxidase-mediated aerobic and anaerobic oxidations of 3-alkylindoles
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Little is known about the HRP-mediated oxidations of 3-alkylindoles. Whereas 3-methylindole and 3-ethylindole were found to be turned over smoothly by HRP, reactions of tryptophol and N-acetyltryptamine were inefficient. Oxidations of the former two indoles by HRP under aerobic conditions led to the corresponding ring-opened o-acylformanilides and oxindoles, whereas anaerobic oxidations resulted in oxidative dimerization. The major products of anaerobic oxidation of 3-methylindole were shown to be two hydrated dimers, while anhydrodimers were obtained in the 3-ethyl case. The proposed mechanism involves HRP-mediated one-electron oxidation to give an indole radical that either dimerizes (anaerobic conditions) or reacts with O2 (aerobic conditions). Measured kinetics of indole oxidation by HRP compounds I and II mirrored their relative reactivities under turnover conditions. The observed comparable binding affinities for all four indole substrates investigated suggest that the low reactivity of tryptophol and N-acetyltryptamine reflect binding to HRP in an orientation that is disadvantageous to electron transfer oxidation of the indole ring.
- Ling, Ke-Qing,Sayre, Lawrence M.
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- Synthesis of DPIE [2-(1,2-Diphenyl-1H-indol-3-yl)ethanamine] Derivatives and Their Regulatory Effects on Pro-Inflammatory Cytokine Production in IL-1β-Stimulated Primary Human Oral Cells
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Interleukin-1 beta (IL-1β) has diverse physiological functions and plays important roles in health and disease. In this report, we focus on its function in the production of pro-inflammatory cytokines, including IL-6 and IL-8, which are implicated in several autoimmune diseases and host defense against infection. IL-1β activity is markedly dependent on the binding affinity toward IL-1 receptors (IL-1Rs). Several studies have been conducted to identify suitable small molecules that can modulate the interactions between 1L-1β and 1L-1R1. Based on our previous report, where DPIE [2-(1,2-Diphenyl-1H-indol-3-yl)ethanamine] exhibited such modulatory activity, three types of DPIE derivatives were synthesized by introducing various substituents at the 1, 2, and 3 positions of the indole group in DPIE. To predict a possible binding pose in complex with IL-1R1, a docking simulation was performed. The effect of the chemicals was determined in human gingival fibroblasts (GFs) following IL-1β induction. The DPIE derivatives affected different aspects of cytokine production. Further, a group of the derivatives enabled synergistic pro-inflammatory cytokine production, while another group caused diminished cytokine production compared to DPIE stimulation. Some groups displayed no significant difference after stimulation. These findings indicate that the modification of the indole site could modulate IL-1β:IL1R1 binding affinity to reduce or enhance pro-inflammatory cytokine production.
- Jung, Seunggon,Kim, Eunae,Lee, Sunwoo,Lee, Tae-Hoon,Lim, Jeongah,Seong, Jihyoun
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- Ir(iii)-Catalysed electrooxidative intramolecular dehydrogenative C-H/N-H coupling for the synthesis of N-H indoles
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Herein, an iridium(iii)-catalysed electrooxidative intramolecular dehydrogenative C-H/N-H coupling of unprotected 2-alkenyl anilines is described. The developed method allows the synthesis of a variety of 3-substituted N-H indole scaffolds under undivided electrolytic conditions. Mechanistic studies suggest that the reaction proceeds through the electro-oxidation induced reductive elimination pathway.
- Chang, Sukbok,Kim, Dongwook,Kim, Youyoung
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p. 12309 - 12312
(2021/12/07)
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- KOH-mediated stereoselective alkylation of 3-bromooxindoles for the synthesis of 3,3′-disubstituted oxindoles with two contiguous all carbon quaternary centres
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The stereoselective synthesis of 3,3′-disubstituted oxindoles having all-carbon quaternary stereocenters has been achieved using KOH as a base with an excellent diastereomeric ratio (98?:?2). The practicability of the present methodology has been validated with the synthesis of a series of substrates in good to excellent yields. The aesthetic simplicity, accessibility, and eco-friendly base (KOH) have prompted the broader application of the present methodology in organic synthesis.
- Devi, Manju,Jadhav, Amol P.,Singh, Ravi P.
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p. 8445 - 8448
(2021/05/25)
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- Direct Deamination of Primary Amines via Isodiazene Intermediates
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We report here a reaction that selectively deaminates primary amines and anilines under mild conditions and with remarkable functional group tolerance including a range of pharmaceutical compounds, amino acids, amino sugars, and natural products. An anomeric amide reagent is uniquely capable of facilitating the reaction through the intermediacy of an unprecedented monosubstituted isodiazene intermediate. In addition to dramatically simplifying deamination compared to existing protocols, our approach enables strategic applications of iminium and amine-directed chemistries as traceless methods. Mechanistic and computational studies support the intermedicacy of a primary isodiazene which exhibits an unexpected divergence from previously studied secondary isodiazenes, leading to cage-escaping, free radical species that engage in a chain, hydrogen-atom transfer process involving aliphatic and diazenyl radical intermediates.
- Berger, Kathleen J.,Driscoll, Julia L.,Yuan, Mingbin,Dherange, Balu D.,Gutierrez, Osvaldo,Levin, Mark D.
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supporting information
p. 17366 - 17373
(2021/11/04)
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- Compound containing indole ring structure, preparation method and application of compound, and bactericide
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The invention belongs to the field of pesticides and discloses a compound containing an indole ring structure, a preparation method and application of the compound and a bactericide. The compound has the structure shown in the formula (I), and the compound has an excellent prevention and treatment effect on cucumber downy mildew, is equivalent to the current commercial oomycete disease prevention and treatment agent oxathiapiprolin, and has a good market development prospect.
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Paragraph 0080; 0085; 0086; 0087
(2021/07/31)
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- Cu-Catalyzed Dimerization of Indole Derived Oxime Acetate for Synthesis of Biimidazo[1,2- a]indoles
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A copper-mediated cyclization and dimerization of indole derived oxime acetate was developed to generate a series of biimidazo[1,2-a]indole scaffolds with two contiguous stereogenic quaternary carbons in one step.
- Xie, Tao,Sui, Qi-Bang,Qin, Lu-Zhe,Wen, Xiaoan,Sun, Hongbin,Xu, Qing-Long,Zhen, Le
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supporting information
p. 5518 - 5529
(2021/05/04)
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- Constructing Saturated Guanidinum Heterocycles by Cycloaddition of N-Amidinyliminium Ions with Indoles
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We report that structurally complex guanidinium heterocycles can be prepared in one step by regio- and stereoselective [4 + 2]-cycloadditions of N-amidinyliminium ions with indoles or benzothiophene. In contrast to reactions of these heterodienes with alkenes, density functional theory (DFT) calculations show that these cycloadditions take place in a concerted asynchronous fashion. The [4 + 2]-cycloaddition of N-amidinyliminium ions (1,3-diaza-1,3-dienes) with indoles and benzothiophene are distinctive, as related [4 + 2]-cycloadditions of N-acyliminium ions (1-oxa-3-aza-1,3-dienes) are apparently unknown.
- Allred, Tyler K.,Shaghafi, Michael B.,Chen, Pan-Pan,Tran, Quan,Houk,Overman, Larry E.
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supporting information
p. 7618 - 7623
(2021/10/12)
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- Organocatalytic Formal (3 + 2) Cycloaddition toward Chiral Pyrrolo[1,2- a]indoles via Dynamic Kinetic Resolution of Allene Intermediates
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We report the chiral phosphoric acid catalyzed formal (3 + 2) cycloaddition of 3-substituted 1H-indoles and propargylic alcohols containing a functional directing group (p-NHAc or p-OH). This work represents a straightforward method to synthesize chiral pyrrolo[1,2-a]indole bearing a tetrasubstituted carbon stereocenter. The reaction proceeds smoothly with a wide array of substrate tolerance to deliver various chiral pyrrolo[1,2-a]indoles in up to 93percent yield and 98percent ee. The utility of this method is highlighted by the diverse transformations of the products into various indole derivatives.
- Bai, Jian-Fei,Zhao, Lulu,Wang, Fang,Yan, Fachao,Kano, Taichi,Maruoka, Keiji,Li, Yuehui
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supporting information
p. 5439 - 5445
(2020/07/14)
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- Ruthenium Pincer Complex Catalyzed Selective Synthesis of C-3 Alkylated Indoles and Bisindolylmethanes Directly from Indoles and Alcohols
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Herein, we presented Ru-SNS complex that serves as a useful catalyst for C-3 alkylation of 1H-indoles with various aliphatic primary and secondary alcohols including cyclic alcohols as well as benzylic alcohols. The selective synthesis of bisindolylmethane derivatives is also achieved from the same set of indole and alcohol just by altering the reaction parameters. Furthermore, the sustainable synthesis of C-3 alkylated indoles directly from 2-(2-nitrophenyl)ethan-1-ol and alcohols catalysed by a Ru-complex via “borrowing hydrogen” strategy is reported. This protocol provides an atom-economical sustainable route to access structurally important compounds like arundine, vibrindole A and tryptamine based derivatives. (Figure presented.).
- Biswas, Nandita,Sharma, Rahul,Srimani, Dipankar
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p. 2902 - 2910
(2020/06/03)
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- Preparation method of alkyl aromatic compound based on alkenyl ether Friedel-Crafts reaction
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The invention discloses a preparation method of an alkyl aromatic compound based on an alkenyl ether Friedel-Crafts reaction, and belongs to the technical field of pharmaceutical and chemical intermediates and related chemistry. According to the method, alkenyl ether and an aromatic compound are used as raw materials, and green and efficient synthesis of the alkyl-substituted aromatic compound isrealized under the catalytic action of Lewis acid or protonic acid. The method has the advantages of high selectivity, mild reaction conditions, good functional group compatibility, the wide substraterange, environmental friendliness and the like. The alkyl-substituted aromatic compound is an important organic synthesis intermediate and has very wide application in the fields of organic synthesisand pharmacy, so that the alkyl-substituted aromatic compound has relatively high application value and social and economic benefits.
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Paragraph 0051-0053; 0055-0056; 0058
(2020/07/24)
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- Monoamine Oxidase (MAO-N) Biocatalyzed Synthesis of Indoles from Indolines Prepared via Photocatalytic Cyclization/Arylative Dearomatization
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The biocatalytic aromatization of indolines into indole derivatives exploiting monoamine oxidase (MAO-N) enzymes is presented. Indoline substrates were prepared via photocatalytic cyclization of arylaniline precursors or via arylative dearomatization of unsubstituted indoles and in turn chemoselectively aromatized by the MAO-N D11 whole cell biocatalyst. Computational docking studies of the indoline substrates in the MAO-N D11 catalytic site allowed for the rationalization of the biocatalytic mechanism and experimental results of the biotransformation. This methodology represents an efficient example of biocatalytic synthesis of indole derivatives and offers a facile approach to access these aromatic heterocycles under mild reaction conditions.
- Black, Gary W.,Brancale, Andrea,Castagnolo, Daniele,Colonna, Serena,Ferla, Salvatore,Masci, Domiziana,Turner, Nicholas J.,Varricchio, Carmine,Zhao, Fei
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p. 6414 - 6421
(2020/07/09)
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- Manganese-Catalyzed Regioselective Dehydrogenative C-versus N-Alkylation Enabled by a Solvent Switch: Experiment and Computation
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The first base metal-catalyzed regioselective dehydrogenative alkylation of indolines using readily available alcohols as the alkylating reagent is reported. A single air-and moisture-stable manganese catalyst provides access to either C3-or N-alkylated indoles depending on the solvent used. Mechanistic studies indicate that the reaction takes place through a combined acceptorless dehydrogenation and hydrogen autotransfer strategy.
- Borghs, Jannik C.,Zubar, Viktoriia,Zubar, Viktoriia,Azofra, Luis Miguel,Sklyaruk, Jan,Rueping, Magnus,Rueping, Magnus
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supporting information
p. 4222 - 4227
(2020/06/04)
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- Recyclable Pd/C catalyzed one-step reduction of carbonyls to hydrocarbons under simple conditions without extra base
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The reductions of carbonyls for the synthesis of hydrocarbons were developed with hydrazine hydrate, hydrogen gas and ammonium formate respectively. The simple, mild and efficient conditions were provided by employing recyclable Pd/C as catalyst in normal solvents at 100 °C and the reactions proceeded smoothly to produce the corresponding products with good to excellent yields. And gram-scale reactions and recycling of the catalyst were also demonstrated. Furtherly, the mechanism has been proposed.
- Zhou, Xiao-Yu,Chen, Xia
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supporting information
(2019/12/06)
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- Bifunctional Iron Complexes Catalyzed Alkylation of Indoles
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Cyclopentadienone iron carbonyl complexes have been applied in alkylation of indoles with various benzylic alcohols, aliphatic alcohols (butanol, ethanol, methanol and 2-methylpentanol) via the hydrogen autotransfer strategy in mild reaction conditions. Experimental works highlight the role of the bifunctional iron complexes and the base. These iron complexes demonstrated a broad applicability in mild conditions and extended the scope of substrates in iron catalyzed C?C bond formation. (Figure presented.).
- Seck, Charlotte,Mbaye, Mbaye Diagne,Gaillard, Sylvain,Renaud, Jean-Luc
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supporting information
p. 4640 - 4645
(2018/10/31)
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- Fluorine as a Traceless Directing Group for the Regiodivergent Synthesis of Indoles and Tryptophans
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Despite ample evidence for the unique reactivity offered by hypervalent F-iodanes, mechanistic investigations fall far behind. In order to shed light on the unusual behavior of such F-reagents, we conducted computational and experimental studies on the chemodivergent transformation of styrenes. We identified the spirocyclic F-cyclopropane as the common intermediate for both the C,H-fluorination and C,H-amination pathways. The fate of this key compound is determined by the extent of cationic charge delocalization controlled by the N-substituents. Exploiting this phenomenon, a multitude of different transformations have become available, leading, i.e., to the regiodivergent synthesis of indoles and tryptophans.
- Andries-Ulmer, Anna,Brunner, Christoph,Rehbein, Julia,Gulder, Tanja
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supporting information
p. 13034 - 13041
(2018/09/27)
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- Enantioselective 2-alkylation of 3-substituted indoles with dual chiral lewis acid/hydrogen-bond-mediated catalyst
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A chiral-at-metal bis-cyclometalated iridium complex combines electrophile activation via metal coordination with nucleophile activation through hydrogen bond formation. This new bifunctional chiral Lewis acid/hydrogenbond-mediated catalyst permits the challenging enantioselective 2-alkylation of 3-substituted indoles with α, β-unsaturated 2-acyl imidazoles in up to 99% yield and with up to 98% enantiomeric excess at a catalyst loading of 2 mol %. As an application, the straightforward synthesis of a chiral pyrrolo- [1, 2-a]indole is demonstrated.
- Zhou, Zijun,Li, Yanjun,Gong, Lei,Meggers, Eric
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supporting information
p. 222 - 225
(2017/11/27)
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- Divergent dehydrogenative coupling of indolines with alcohols
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The dehydrogenative coupling of indolines with alcohols catalyzed by an iridium complex has been achieved to afford both N- and C3-alkylated indoles selectively, by simply changing the addition time of a base additive. The iridacycle catalyst plays multiple roles in these reactions, which dehydrogenates both amines and alcohols and catalyzes the coupling reactions. Mechanistic studies reveal that a borrowing hydrogen-dehydrogenation process and a dehydrogenationborrowing hydrogen process are involved in N-alkylation and C3-alkylation reactions, respectively. The C3-alkylation reaction involves the direct coupling of two sp3 carbon centers.
- Jiang, Xue,Tang, Weijun,Xue, Dong,Xiao, Jianliang,Wang, Chao
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p. 1831 - 1835
(2017/08/01)
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- Palladium/Phosphorus-Doped Porous Organic Polymer as Recyclable Chemoselective and Efficient Hydrogenation Catalyst under Ambient Conditions
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A new type of phosphorus-doped porous organic polymer (POP) has been readily synthesized through a Heck reaction, which could be used not only as a support but also a ligand for palladium nanoparticles. The dual-functional material supported palladium nanocatalyst was used for the efficient and chemoselective hydrogenation of varieties of nitroarenes and α,β-unsaturated compounds, as well as for the synthesis of indoles from 2-nitrophenylacetonitrile under 1 atm hydrogen in green solvents at room temperature. No obvious aggregation and loss of catalytic activity of the new nanocatalyst were observed after 10 runs in the reaction. (Figure presented.).
- Ding, Zong-Cang,Li, Cun-Yao,Chen, Jun-Jia,Zeng, Jia-Hao,Tang, Hai-Tao,Ding, Yun-Jie,Zhan, Zhuang-Ping
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p. 2280 - 2287
(2017/07/07)
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- Light-Mediated Reductive Debromination of Unactivated Alkyl and Aryl Bromides
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Cleavage of carbon-halogen bonds via either single-electron reduction or atom transfer is a powerful transformation in the construction of complex molecules. In particular, mild, selective hydrodehalogenations provide an excellent follow-up to the application of halogen atoms as directing groups or the utilization of atom transfer radical addition (ATRA) chemistry for the production of hydrocarbons. Here we combine the mechanistic properties of photoredox catalysis and silane-mediated atom transfer chemistry to accomplish the hydrodebromination of carbon-bromide bonds. The resulting method is performed under visible light irradiation in an open vessel and is capable of the efficient reduction of a variety of unactivated alkyl and aryl substrates.
- Devery, James J.,Nguyen, John D.,Dai, Chunhui,Stephenson, Corey R. J.
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p. 5962 - 5967
(2016/09/09)
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- Active and Recyclable Catalytic Synthesis of Indoles by Reductive Cyclization of 2-(2-Nitroaryl)acetonitriles in the Presence of Co-Rh Heterobimetallic Nanoparticles with Atmospheric Hydrogen under Mild Conditions
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A cobalt-rhodium heterobimetallic nanoparticle-catalyzed reductive cyclization of 2-(2-nitroaryl)acetonitriles to indoles has been achieved. The tandem reaction proceeds without any additives under the mild conditions (1 atm H2 and 25 °C). This procedure could be scaled up to the gram scale. The catalytic system is significantly stable under these reaction conditions and could be reused more than ten times without loss of catalytic activity.
- Choi, Isaac,Chung, Hyunho,Park, Jang Won,Chung, Young Keun
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p. 5508 - 5511
(2016/11/17)
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- Commutative reduction of aromatic ketones to arylmethylenes/alcohols by hypophosphites catalyzed by Pd/C under biphasic conditions
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An efficient method is reported to reduce aromatic ketones selectively into arylmethylenes or alcohols with hypophosphites and Pd/C, depending on the selected conditions. This study could represent a promising alternative to the classical uses of standard hydrides or molecular hydrogen involved in reduction and deoxygenation procedures.
- Guyon, Carole,Baron, Marc,Lemaire, Marc,Popowycz, Florence,Métay, Estelle
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p. 2088 - 2095
(2014/03/21)
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- Direct oxidative coupling of N-acetyl indoles and phenols for the synthesis of benzofuroindolines related to phalarine
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Inspired by the biogenetic synthesis of benzofuro-indoline-containing natural products, we designed an oxidative coupling between phenol and N-acetyl indoles. This straightforward and direct radical process, mediated by 2,3-dichloro-5,6-dicyano-1,4-benzoquinone and FeCl 3 allowed the regioselective synthesis of benzofuro[3,2-b]indolines, whose structure is found in the natural product phalarine.
- Tomakinian, Terry,Guillot, Rgis,Kouklovsky, Cyrille,Vincent, Guillaume
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supporting information
p. 11881 - 11885
(2015/01/09)
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- Palladium-catalysed dehydrogenative generation of imines from amines. A nature-inspired route to indoles via cross-couplings of amines with arylhydrazines
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H-substituted imines are elusive compounds formed when aldehydes or ketones are mixed with ammonia. However, this class of molecules can be prepared through selective removal of a hydrogen molecule from a primary amine using a transition metal catalyst. This biomimetic transformation, previously employed for the N-alkylation of anilines, is applied here to a domino preparation of differently substituted indoles from aliphatic primary amines and arylhydrazines. Several different linear and branched aliphatic primary amines are oxidized with reusable palladium on charcoal to the corresponding primary imines entrapped as arylhydrazones that can be isolated as such. Arylhydrazones can be further converted into N-alkylindole derivatives via an acid-mediated indolisation reaction. The one-pot domino hydrogen transfer Fischer indole synthesis under heterogeneous catalysis is also possible, giving access to diverse substituted indoles, including NH indoles obtained after deprotection of the corresponding benzyl compounds. The truly heterogeneous nature of the catalyst was demonstrated by recycling the catalyst in the same reaction, and in other palladium-catalysed transformations.
- Taddei, Maurizio,Mura, Manuel G.,Rajam?ki, Suvi,De Luca, Lidia,Porcheddu, Andrea
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p. 3002 - 3013
(2014/03/21)
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- Use of primary amines for the selective n-alkylation of anilines by a reusable heterogeneous catalyst
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Traditionally, anilines can be alkylated with reactive alkyl halides but now more safe reagents such as alcohols or even amines can be used. To overcome the limits of homogeneous catalysis for aniline N-alkylation, we have developed a protocol that employs simple Pd/C as a heterogeneous catalyst under microwave dielectric heating. The process, based on the easy Pd-mediated oxidation of primary amines to imines followed by aniline addition, is characterized by a high atom economy as ammonia is the only other product of the reaction. This kind of aniline alkylation with amines has been carried out both in ionic liquid medium using [bmim]PF6 or in a more traditional solvent such as THF where the catalyst could be successfully recycled more times. The reusability of the catalyst was further confirmed by using material recycled from the amination in a standard alkene hydrogenation without loss of efficiency. Georg Thieme Verlag Stuttgart New York.
- Linciano, Pasquale,Pizzetti, Marianna,Porcheddu, Andrea,Taddei, Maurizio
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p. 2249 - 2254
(2013/11/06)
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- Schischkiniin support studies: Synthetic access to 1,1′-bisindoles
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The first general synthetic approach to 1,1′-bisindoles is described. Two simultaneous, ambient temperature Mori-Ban reactions were used to effect bisindolization of several diallylated hydrazobenzenes with minimal cleavage of the N-N bond.
- Wang, Christy,Sperry, Jonathan
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supporting information
p. 4349 - 4351
(2013/06/27)
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- From alcohols to indoles: A tandem Ru catalyzed hydrogen-transfer Fischer indole synthesis
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In a new version of the Fischer indole synthesis, primary and secondary alcohols have been catalytically oxidized in the presence of phenylhydrazines and protic or Lewis acids to give the corresponding indoles. The overall reaction can be accomplished in one step, and the use of alcohols instead of aldehyes or ketones as starting materials has several advantages in terms of a large selection of reagents, easy handling, and safety of the process.
- Porcheddu, Andrea,Mura, Manuel G.,De Luca, Lidia,Pizzetti, Marianna,Taddei, Maurizio
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supporting information
p. 6112 - 6115
(2013/02/25)
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- Synthetic applications of the nickel-catalyzed cyclization of alkynes combined with addition reactions in a domino process
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Carbonickelations of alkynes and functionalization of the resulting vinylnickel moiety have been performed efficiently in a nickel-catalyzed domino cyclization-condensation process. This reaction, which does not require the preparation of any other organometallic reagent, proceeds only by exo-dig cyclization. This convenient and mild method constitutes a one-pot synthesis of substituted dihydrobenzofurans, chromans, isochromans, indoles, or indanes. Theses valuable products are generally obtained in good yields and high stereoselectivity. They are shown to be useful synthons for rapid access to functionalized polycyclic skeletons. Yes nickel can! Carbonickelation of alkynes and functionalization of the resulting vinylnickel moiety occurs efficiently. Overall, a domino cyclization-condensation process propagated by substoichiometric nickel catalysis takes place (see scheme). This one-pot synthesis provides substituted polyheterocyclic compounds in good yields and high stereoselectivity.
- Durandetti, Muriel,Hardou, Lucie,Lhermet, Rudy,Rouen, Mathieu,Maddaluno, Jacques
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p. 12773 - 12783
(2011/12/04)
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- Synthesis of 3-ethyl indole
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In this study, it is planned to synthesize intermediates to get β-carboline alkaloids having effective bioligical activities. In this way, we tried to synthesize 3-ethyl indole as an intermediate from simple and cheap compounds to obtain the β-carboline s
- Karaboyaci, Mustafa,Gülce, Ahmet
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experimental part
p. 3295 - 3296
(2012/02/02)
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- Electron transfer activity of a cobalt crown carbene complex
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The novel cobalt(II) crown carbene complex 12(II) has been prepared and characterised by X-ray crystallography. This complex is reduced in a one-electron process to a cobalt(I) complex that acts as a powerful single electron donor, reducing aryl halides,
- Park, Stuart R.,Findlay, Neil J.,Garnier, Jean,Zhou, Shengze,Spicer, Mark D.,Murphy, John A.
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supporting information; experimental part
p. 10756 - 10761
(2010/03/01)
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- Reaction pathway in the vapour-phase synthesis of indole and alkylindoles
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The vapour-phase synthesis of indole and its derivatives from aniline or alkylanilines and ethylene glycol or other diols was investigated with the use of a novel ZrO2/SiO2 (5:95 w/w) catalyst to check the applicability of this synthesis to a wide number of alkylindoles. During feeding with alkylaniline, the above catalyst showed catalytic results better than those reported in the literature, and a very good regenerability. In particular, with ethylene glycol, the best yields in the corresponding indoles were obtained when a C2-C3 alkyl chain was located in the ortho position to the amino group. The differences in reactivity between aniline and alkylaniline were significantly reduced when the length of the diol chain was increased and eliminated with 2,3-butanediol. On the basis of the above data and those collected sharing the synthesis in single steps, a possible overall reaction pathway was proposed to design a better tailor-made catalyst. It was also indicated that the formation of heavy compounds, which are able to deactivate the catalyst, were not derived from the reagents or the following reactions on the indole formed, but might be mainly attributed to the polycondensation of an aldehyde intermediate.
- Campanati,Franceschini,Piccolo,Vaccari
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- Tributylgermanium hydride as a replacement for tributyltin hydride in radical reactions
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Tributylgermanium hydride (Bu3GeH) can be used as an alternative to tributyltin hydride (Bu3SnH) as a radical generating reagent with a wide range of radical substrates. Tributylgermanium hydride has several practical advantages over tributyltin hydride, e.g. low toxicity, good stability and much easier work-up of reactions. The reagent can be easily prepared in good yield and stored indefinitely. Suitable substrates include iodides, bromides, activated chlorides, phenyl selenides, tert-nitroalkanes, thiocarbonylimidazolides and Barton esters. Alkyl, vinyl and aryl radicals can be generated in radical reactions including reduction and cyclisation processes. Common radical initiators such as ACCN and triethylborane can be used. The slower rate of hydrogen abstraction by carbon-centred radicals from Bu 3GeH as compared to Bu3SnH facilitates improved cyclisation yields. Polarity reversal catalysis (PRC) with phenylthiol can be used in reactions which generate stable radical intermediates which will not abstract hydrogen from Bu3GeH.
- Bowman, W. Russell,Krintel, Sussie L.,Schilling, Mark B.
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p. 585 - 592
(2007/10/03)
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- A METHOD OF INDOLE SYNTHESIS
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The present invention relates to methods for the synthesis of indoles. In particular, the invention relates to the coupling of an a-haloenone or a-haloenal with an ortho-halonitroarene to form an ortho-(enone)nitroarene or ortho-(enal)nitroarene. Reductive cyclization of an ortho-(enone)nitroarene or ortho-(enal)nitroarene affords access to indole compounds.
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- Synthesis of indoles via palladium[0]-mediated ullmann cross-coupling of o-halonitroarenes with α-halo-enones or -enals
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(Matrix presented) Palladium[0]-mediated Ullmann cross-coupling of o-halonitrobenzene (1) and various related nitroarenes with a range of α-halo-enones (e.g., 2) or -enals readily affords the expected α-arylenones, e.g., 3, or -enals, which are converted into the corresponding indoles, e.g., 4, on reaction with dihydrogen in the presence of Pd on C.
- Banwell, Martin G.,Kelly, Brian D.,Kokas, Okanya J.,Lupton, David W.
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p. 2497 - 2500
(2007/10/03)
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- Observations on the intramolecular Heck reactions of aromatic chlorides using palladium/imidazolium salts
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The intramolecular Heck reaction of aromatic amines and ethers using palladium/imidazolium salts is described. The use of tetra-n-butylammonium halide salts facilitates the reactivity of aromatic chlorides. An unexpected and novel palladium-mediated cyclisation is also described leading to the formation of a tricyclic adduct.
- Caddick, Stephen,Kofie, William
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p. 9347 - 9350
(2007/10/03)
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- Novel [1,5] sigmatropic rearrangements of cyclohexadienones generated from fischer carbene complexes. A new strategy for installing the C-20 angular ethyl group in aspidospermidine alkaloids
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(Equation Presented) We report here the first examples of a [1,5] sigmatropic rearrangement in a 4a-alkyl-4a-hydrocarbazol-4-one to yield a 3-alkylcarbazol-4-one with a re-aromatized indole nucleus. The reaction of 1-methyl-3-substituted-indole-2-carbene
- Quinn, John F.,Bos, Mary Ellen,Wulff, William D.
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p. 161 - 164
(2008/03/11)
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- Photoinduced reduction of group 16 heteroatom compounds with the aid of samarium diiodide
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A novel photoinduced reduction of group 16 heteroatom compounds such as organic selenides, tosylates, and tellurides has been developed. In particular, organic selenides, which can not be reduced with SmI2 in the dark (or even in the presence of HMPA), undergo reductive cleavage efficiently by using the SmI2-hv system.
- Ogawa, Akiya,Ohya, Syoji,Doi, Mikio,Sumino, Yukihito,Sonoda, Noboru,Hirao, Toshikazu
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p. 6341 - 6342
(2007/10/03)
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- Novel enhancement of the reducing ability of ytterbium diiodide by irradiation with near-UV light
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Irradiation with near-UV light dramatically enhances the reducing ability of ytterbium diiodide (Ybl2). Organic bromides, iodides, tosylates, and tellurides are reduced efficiently by a YbI2-hv system, while these can not be reduced with YbI2 in the dark.
- Ogawa, Akiya,Ohya, Syoji,Sumino, Yukihito,Sonoda, Noboru,Hirao, Toshikazu
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p. 9017 - 9018
(2007/10/03)
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- 29. Synthesis of Indole Derivatives by [2 + 2] Photocycloaddition of Indoline-2-thiones with Alkenes and Photodesulfurization of Indoline-2-thiones
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The photochemical synthesis of indole derivatives starting from the indoline-2-thiones 1 is described. Irradiation of indoline-2-thiones 1 in the presence of alkenes 3 gave 2-alkyl-3H-indoles 4-7 or 2-alkylindoles 8-22 through the ring cleavage of the intermediates, spirocyclic amino-thietanes, initially derived by [2 + 2] cycloaddition of the C=S bond of 1 and the C=C bond of 3. Irradiation of 1 in the presence of trialkylamines 26 gave desulfurization products 27-32 and unexpected 3-alkylindoles 33-40. N-Acylindoline-2-thiones 1l-p yielded the deacylated products, indoline-2-thiones 1a-b, and ethyl esters 43 through γ-H abstraction by the excited thioamide S-atom when irradiated in CDCl3/EtOH or benzene/EtOH. Oxygen analogues 2a-d also underwent intramolecular H abstraction to give the indolin-2-ones 2e-f and ethyl esters 43 in a similar way.
- Nishio, Takehiko,Oka, Mitsuru
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p. 388 - 397
(2007/10/03)
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- 3-lithio-1-(triisopropylsilyl)indole, preparation and reactions with electrophilic reagents
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3-Lithio-1-(triisopropylsilyl)indole (2) is prepared by halogenmetal exchange from the corresponding 3-bromoindole and regioselectively reacts with a variety of electrophilic reagents to give 3-substituted indoles.
- Amat, Mercedes,Sathyanarayana, Swargam,Hadida, Sabine,Bosch, Joan
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p. 1713 - 1718
(2007/10/03)
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- Preparation and Reactions of 1-(tert-Butyldimethylsilyl)-3-lithioindole. Regioselective Synthesis of 3-Substituted Indoles
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1-(tert-Butyldimethylsilyl)-3-lithioindole (2) is prepared by metalation of the corresponding 3-bromo derivative 1 and efficiently reacts with electrophiles to give 3-substituted indoles 3 and 4.
- Amat, Mercedes,Hadida, Sabine,Sathyanarayana, Swargam,Bosch, Joan
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- SYNTHESIS OF NITROGEN HETEROCYCLES VIA PALLADIUM-CATALYZED INTRAMOLECULAR CYCLIZATION
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Catalytic amounts of Pd(OAc)2 in the presence of n-Bu4NCl, DMF and an appropriate base (Na2CO3, NaOAc or Et3N) cyclize nitrogen-containing o-iodoaryl alkenes to indoles, indolines, oxindoles, quinolines, isoquinolines and isoquinolones in short reaction times, under mild temperatures, and in high yields.
- Larock, Richard C.,Babu, Srinivasan
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p. 5291 - 5294
(2007/10/02)
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- SYNTHESIS OF ALKYLINDOLES IN GAS PHASE ON AN ALUMINIUM ORTHOPHOSPHATE
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The synthesis of alkylindoles in the gas phase over an aluminium orthophosphate Kearby type catalyst has been studied.As reactants different carbonyl compounds and phenylhydrazine or aniline have been employed.The conditions of temperature and molar ratio of carbonyl compoud/nitrogenous compound have been changed.The best results were reached in the reactions between the lower aldehydes and aniline.Thus, 75 percent alkylindoles were obtained from propanaldehyde and 62 percent from butyraldehyde.Also remarkable is the reaction between cyclopentanone and phenylhydrazine because 45 percent 2,3-trimethyleneindole was obtained.
- Esteban, S.,Marinas, J. M.,Martinez-Alcazar, M. P.,Martinez, M.,Agarrabeitia, A. R.
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p. 715 - 720
(2007/10/02)
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