- Synthesis and characterization of Trichloroisocyanouric acid functionalized mesoporous silica nanocomposite (SBA/TCCA) for the Acylation of Indole
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Trichloroisocyanouric acid (TCCA)-functionalized mesoporous silica nanocomposites (SBA/ TCCA) were synthesized and characterized for the acylation of indole. The uniform incorporation of TCCA inside the SBA-15 matrix was confirmed by standard characteriza
- Wilson, G Robin,Dubey, Amit
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- HETEROCYCLIC SYNTHESIS VIA THALLATION AND SUBSEQUENT PALLADIUM-PROMOTED OLEFINATION
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The thallation and subsequent palladium-promoted olefination of p-tolylacetic acid, N-methylbenzamide, benzamide and acetanilide provides a novel new route to a variety of important oxygen and nitrogen heterocycles.
- Larock, R.C.,Liu, C.-L.,Lau, H. H.,Varaprath, S.
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- A Catalytic Construction of Indoles via Formation of Ruthenium Vinylidene Species from N-Arylynamides
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Treatment of ynamides with a catalytic amount of TpRuCl(PPh3)2 resulted in the construction of indole scaffolds known as privileged structure motifs. This reaction involved a cascade of 1,2-rearrangement and cyclization carrying out C?C bond formation via a ruthenium vinylidene intermediate, as revealed by a deuterium-labeling experiments. Furthermore, the transformation of multi-functionalized ynamide, derived from a practical drug molecule, showed a high functional group tolerance of this reaction. (Figure presented.).
- Tayu, Masanori,Watanabe, Ryuta,Isogi, Satoshi,Saito, Nozomi
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supporting information
p. 1147 - 1151
(2021/01/04)
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- An efficient catalytic method for the c-n acylation of heterocycles by schiff base co(Ii), ni(ii), cu(ii) and zn(ii) transition metal complexes
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The catalytic activity of Schiff base Co(II), Ni(II), Cu(II) and Zn(II) transition metal complexes was tested for N-Acylation of heterocycles with acetyl chloride. It is observed that all the complexes worked as efficient catalysts. The structural type of complexes was studied by an X-ray powder diffractogram (XRD). The mixed ligand complexes with PPh3 ligand show greater activity as compared to Phen complexes and Schiff base complexes. Especially complex [Ni(L)(PPh3)2Cl2] efficiently worked as a catalyst because of high thermal stability (TGA-DSC) and large catalytic surface area (BET).
- Hegade, Sujit,Gaikwad, Gautam,Jadhav, Yuvraj,Chavan, Sanjay,Mulik, Ganpatrao
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p. 611 - 616
(2021/09/30)
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- Ascorbic Acid as an Aryl Radical Inducer in the Gold-Mediated Arylation of Indoles with Aryldiazonium Chlorides
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In recent years interest in the development of protocols that facilitate the oxidative addition of gold to access mild cross-coupling processes mediated by this metal has increased. In this context, we report herein that ascorbic acid, a natural and readily accessible antioxidant, can be used to accelerate the oxidative addition of aryldiazonium chlorides onto AuI. The aryl–AuIII species generated in this way, has been used to prepare 3-arylindoles in a one-pot protocol starting from anilines and para-, meta-, and ortho- substituted aryldiazonium chlorides. The mechanism underlying the oxidative addition has been examined in detail based on EPR analyses, cyclic voltammetry, and DFT calculations. Interestingly, we have found that in this protocol, the chloride atom induces the AuII/AuIII oxidation step.
- Medina-Mercado, Ignacio,Asomoza-Solís, Eric Omar,Martínez-González, Eduardo,Ugalde-Saldívar, Victor Manuel,Ledesma-Olvera, Lydia Gabriela,Barquera-Lozada, José Enrique,Gómez-Vidales, Virginia,Barroso-Flores, Joaquín,Frontana-Uribe, Bernardo A.,Porcel, Susana
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supporting information
p. 634 - 642
(2019/12/11)
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- Iodine-catalyzed convergent aerobic dehydro-aromatization toward benzazoles and benzazines
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An iodine-catalyzed aerobic dehydro-aromatization has been developed, providing straightforward and efficient access to various benzoazoles and benzoazines. The present transition-metal-free protocol enables the dehydro-aromatization of tetrahydrobenzazoles and tetrahydroquinolines with molecular oxygen as the green oxidant, along with some other N-heterocycles. Hence, a broad range of heteroaromatic compounds are generated in moderate to good yields under facile reaction conditions.
- Chen, Shanping,Deng, Guo-Jun,Jiang, Pingyu,Ni, Penghui,Tuo, Xiaolong,Wang, Xiaodong
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p. 8348 - 8351
(2020/03/11)
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- Aerobic oxidative dehydrogenation of N-heterocycles over OMS-2-based nanocomposite catalysts: Preparation, characterization and kinetic study
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OMS-2-based nanocomposites doped with tungsten were prepared for the first time and their remarkably enhanced catalytic activity and recyclability in aerobic oxidative dehydrogenation of N-heterocycles were examined in detail. Many tetrahydroquinoline derivatives and a broad range of other N-heterocycles could be tolerated by the catalytic system using a biomass-derived solvent as a reaction medium. Newly generated mixed crystal phases, noticeably enhanced surface areas and labile lattice oxygen of the OMS-2-based nanocomposite catalysts might contribute to their excellent catalytic performance. Moreover, a kinetic study was extensively performed which concluded that the dehydrogenation of 1,2,3,4-tetrahydroquinoline is a first-order reaction, and the apparent activation energy is 29.66 kJ mol-1
- Bi, Xiuru,Tang, Tao,Meng, Xu,Gou, Mingxia,Liu, Xiang,Zhao, Peiqing
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p. 360 - 371
(2020/02/04)
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- Ir-Catalyzed Reversible Acceptorless Dehydrogenation/Hydrogenation of N-Substituted and Unsubstituted Heterocycles Enabled by a Polymer-Cross-Linking Bisphosphine
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The polystyrene-cross-linking bisphosphine ligand PS-DPPBz was effective for the Ir-catalyzed reversible acceptorless dehydrogenation/hydrogenation of N-heterocycles. Notably, this protocol is applicable to the dehydrogenation of N-substituted indoline derivatives with various N-substituents with different electronic and steric natures. A reaction pathway involving oxidative addition of an N-adjacent C(sp3)-H bond to a bisphosphine-coordinated Ir(I) center is proposed for the dehydrogenation of N-substituted substrates.
- Zhang, Deliang,Iwai, Tomohiro,Sawamura, Masaya
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supporting information
p. 5240 - 5245
(2020/07/03)
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- Rhodium-Catalyzed Annulative Coupling Using Vinylene Carbonate as an Oxidizing Acetylene Surrogate
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Transition-metal-catalyzed C-H activation and subsequent oxidative cyclization with alkynes has been a powerful tool for the synthesis of polycyclic aromatic compounds. Despite the substantial progress in this field, it is still a significant challenge to establish synthetic methodologies for the construction of nonsubstituted vinylene-fused aromatics. We herein report a Rh(III)-catalyzed C-H/N-H annulation with vinylene carbonate as an acetylene surrogate. Vinylene carbonate also acts as an internal oxidant to regenerate the Rh(III) species in situ; thus, no external oxidant is required to trigger the oxidative annulation. This protocol is applicable to the direct synthesis of various N-heteroaromatics.
- Ghosh, Koushik,Nishii, Yuji,Miura, Masahiro
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p. 11455 - 11460
(2019/12/02)
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- Selective N1-Acylation of Indazoles with Acid Anhydrides Using an Electrochemical Approach
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An electrochemical synthesis method for the selective N1-acylation of indazoles has been developed. This "anion pool" approach electrochemically reduces indazole molecules generating indazole anions and H2. Acid anhydrides are then introduced to the solution resulting in selective acylation of the N1-position of the indazoles. This procedure can also be applied to the acylation of benzimidazoles and indoles. The reaction can also be performed using a 9 V battery without loss of reaction efficiency.
- DIssanayake, D.M.M. Mevan,Vannucci, Aaron K.
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supporting information
p. 457 - 460
(2019/01/23)
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- Optimizing ligand structure for low-loading and fast catalysis for alkynyl-alcohol and-amine cyclization
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A series of [Ru(Cp/Cp?)(PR2NR′2)(MeCN)]PF6 complexes were prepared, in which the steric and electronic properties of the primary coordination sphere were varied (R = Ph, t-Bu, Bn; and Cp vs. Cp?). These complexes were catalytically active in the cyclization of alkyne substrates with an intramolecular nucleophile (amine or alcohol) to produce 5-and 6-membered heterocycles. The effect of the 1° coordination sphere structure on catalyst performance was evaluated. Steric bulk around the metal centre was a key feature to achieve rapid catalysis at low temperatures. The catalyst [Ru(Cp)(Pt-Bu2NPh2)(MeCN)]PF6 gave a turnover number that was >1 order of magnitude more active than previous catalysts in the cyclization of the benchmark substrate 2-ethynylaniline. This catalyst is tolerant of a diversity of functional groups and is competent at the formation of various substituted indoles.
- Stubbs, James M.,Bridge, Benjamin J.,Blacquiere, Johanna M.
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p. 7928 - 7937
(2019/06/13)
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- Na 2 CO 3-Catalyzed N-Acylation of Indoles with Alkenyl Carboxylates
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The N-acylation of indoles has been accomplished via inorganic base catalysis. It provided an efficient and simple catalysis system for the preparation of N-acylindoles with alkenyl carboxylates as acylating agents. A broad variety of indoles undergo the smooth N-acylation using Na 2 CO 3 as catalyst in MeCN at 120? °C to give the corresponding N-acylindoles in good to excellent yields.
- Zhou, Xiao-Yu,Chen, Xia
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supporting information
p. 516 - 521
(2019/01/10)
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- Efficient acceptorless photo-dehydrogenation of alcohols and: N -heterocycles with binuclear platinum(ii) diphosphite complexes
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Although photoredox catalysis employing Ru(ii) and Ir(iii) complexes as photocatalysts has emerged as a versatile tool for oxidative C-H functionalization under mild conditions, the need for additional reagents acting as electron donor/scavenger for completing the catalytic cycle undermines the practicability of this approach. Herein we demonstrate that photo-induced oxidative C-H functionalization can be catalysed with high product yields under oxygen-free and acceptorless conditions via inner-sphere atom abstraction by binuclear platinum(ii) diphosphite complexes. Both alcohols (51 examples), particularly the aliphatic ones, and saturated N-heterocycles (24 examples) can be efficiently dehydrogenated under light irradiation at room temperature. Regeneration of the photocatalyst by means of reductive elimination of dihydrogen from the in situ formed platinum(iii)-hydride species represents an alternative paradigm to the current approach in photoredox catalysis.
- Zhong, Jian-Ji,To, Wai-Pong,Liu, Yungen,Lu, Wei,Che, Chi-Ming
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p. 4883 - 4889
(2019/05/16)
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- Switchable regioselection of C-H thiolation of indoles using different TMS counterions
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A switchable regioselectivity in C-H thiolation reaction by simply swapping the counteranions of TMS is reported here for the first time. An exclusive C3-H thiolation of indoles with sodium arylsulfinates was achieved in the presence of TMSCl as a promoter. In contrast, with the use of TMSOTf instead of TMSCl under otherwise identical conditions, a regiospecific C2-H thiolation of indoles was realized with the same set of substrates.
- Ji, Yuan-Zhao,Li, Hui-Jing,Zhang, Jin-Yu,Wu, Yan-Chao
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supporting information
p. 11864 - 11867
(2019/10/11)
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- Ring-Opening of Indoles: An Unconventional Route for the Transformation of Indoles to 1 H-Pyrazoles Using Lewis Acid
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An unusual transformation of indoles to pyrazoles via an aromatic ring-opening strategy has been developed. The salient feature of this strategy involves the C2-N1 bond opening and concomitant cyclization reaction of the C2=C3 bond of the indole moiety with the tosylhydrazone, which proceeds under transition-metal and ligand free conditions. This ring-opening functionalization of indoles provides a wide scope of differently substituted pyrazoles.
- Panda, Subhankar,Pradhan, Nirmalya,Manna, Debasis
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supporting information
p. 573 - 578
(2018/09/25)
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- Based on carboxylic acid allyl ester as the acylation reagent N - acyl indoles preparation method (by machine translation)
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Based on carboxylic acid allyl ester as the acylation reagent N - acyl indoles preparation method, which belongs to the medical and chemical intermediates and related chemical technical field. This method uses the indole compounds and carboxylic acid allyl ester as the raw material, in the catalysis of alkali, realizes the N - acyl indoles of green, efficient synthesis. The method has high selectivity, mild reaction conditions, functional group compatibility is good, wide substrate range, environment-friendly and the like. Because the N - acyl indoles is an important organic synthetic intermediates, in organic synthesis and in the field of pharmacy has very wide application, therefore, the invention has great application value and social and economic benefits. (by machine translation)
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Paragraph 0038-0040
(2018/12/02)
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- A general copper-based photoredox catalyst for organic synthesis: Scope, application in natural product synthesis and mechanistic insights
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Organic transformations can broadly be classified into four categories including cationic, anionic, pericyclic and radical reactions. While the last category has been known for decades to provide remarkably efficient synthetic pathways, it has long been hampered by the need for toxic reagents, which considerably limited its impact on chemical synthesis. This situation has come to an end with the introduction of new concepts for the generation of radical species, photoredox catalysis – which simply relies on the use of a catalyst that can be activated upon visible light irradiation – certainly being the most efficient one. The state-of-the-art catalysts mostly rely on the use of ruthenium and iridium complexes and organic dyes, which still considerably limits their broad implementation in chemical processes: alternative readily available catalysts based on inexpensive, environmentally benign base metals are therefore strongly needed. Furthermore, expanding the toolbox of methods based on photoredox catalysis will facilitate the discovery of new light-mediated transformations. This article details the use of a simple copper complex which, upon activation with blue light, can initiate a broad range of radical reactions.
- Deldaele, Christopher,Michelet, Bastien,Baguia, Hajar,Kajouj, Sofia,Romero, Eugenie,Moucheron, Cecile,Evano, Gwilherm
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p. 621 - 629
(2018/10/04)
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- A General Copper Catalyst for Photoredox Transformations of Organic Halides
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A broadly applicable copper catalyst for photoredox transformations of organic halides is reported. Upon visible light irradiation in the presence of catalytic amounts of [(DPEphos)(bcp)Cu]PF6 and an amine, a range of unactivated aryl and alkyl halides were shown to be smoothly activated through a rare Cu(I)/Cu(I)?/Cu(0) catalytic cycle. This complex efficiently catalyzes a series of radical processes, including reductions, cyclizations, and direct arylation of arenes.
- Michelet, Bastien,Deldaele, Christopher,Kajouj, Sofia,Moucheron, Cécile,Evano, Gwilherm
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supporting information
p. 3576 - 3579
(2017/07/17)
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- Dehydrogenation of Nitrogen Heterocycles Using Graphene Oxide as a Versatile Metal-Free Catalyst under Air
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Graphene oxide (GO) has been developed as an inexpensive, environmental friendly, metal-free carbocatalyst for the dehydrogenation of nitrogen heterocycles. Valuable compounds, such as quinoline, 3,4-dihydroisoquinoline, quinazoline, and indole derivatives, have been successfully used as substrates. The investigation of various oxygen-containing molecules with different conjugated systems indicated that both the oxygen-containing groups and large π-conjugated system in GO sheets are essential for this reaction. (Figure presented.).
- Zhang, Jingyu,Chen, Shiya,Chen, Fangfang,Xu, Wensheng,Deng, Guo-Jun,Gong, Hang
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supporting information
p. 2358 - 2363
(2017/07/22)
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- C3-Selective alkenylation of N-acylindoles with unactivated internal alkynes by cooperative nickel/aluminium catalysis
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Highly regio- and stereoselective alkenylation of N-acylindoles with unactivated internal alkynes has been accomplished by cooperative nickel/aluminium catalysis to afford C3-alkenylated indoles. Coordination of the acyl moiety to a bulky aluminium-based Lewis acid plays a crucial role in the selective functionalization at the C3-position by electron-rich nickel(0) catalysis.
- Inoue, Fumiyoshi,Saito, Teruhiko,Semba, Kazuhiko,Nakao, Yoshiaki
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supporting information
p. 4497 - 4500
(2017/04/26)
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- N-Bromosuccinimide (NBS)-Catalyzed C-H Bond Functionalization: An Annulation of Alkynes with Electron Withdrawing Group (EWG)-Substituted Acetyl Indoles for the Synthesis of Carbazoles
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An N-bromosuccinimide-catalyzed intermolecular annulation of acetyl indoles with alkynes was developed, allowing for regioselective formation of valuable carbazoles through direct C-H bond functionalization. The readily available catalyst, wide substrate scope, gram scale synthesis, and mild conditions make this method practical. Mechanistic investigations indicate that the bromination of acetyl indole takes place to generate a bromide intermediate, followed by coupling with an alkyne and intramolecular cycloaromatization to furnish carbazole products.
- Wang, Han,Wang, Zhen,Wang, Yi-Long,Zhou, Rui-Rui,Wu, Guang-Chuan,Yin, Si-Yao,Yan, Xu,Wang, Bin
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supporting information
p. 6140 - 6143
(2017/11/24)
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- Photoredox Catalysis Induced Bisindolylation of Ethers/Alcohols via Sequential C-H and C-O Bond Cleavage
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A visible-light-engaged 2-fold site-selective alkylation of indole derivatives with aliphatic ethers or alcohols has been accomplished for easy access to symmetric 3,3′-bisindolylmethane derivatives. The experimental data suggest a sequential photoredox catalysis induced radical addition and proton-mediated Friedel-Crafts alkylation mechanism.
- Ye, Lu,Cai, Sai-Hu,Wang, Ding-Xing,Wang, Yi-Qiu,Lai, Lin-Jie,Feng, Chao,Loh, Teck-Peng
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supporting information
p. 6164 - 6167
(2017/11/24)
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- Lewis Acid and Fluoroalcohol Mediated Nucleophilic Addition to the C2 Position of Indoles
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Indole readily undergoes nucleophilic substitution at the C3 site, and many indole derivatives have been functionalized using this property. Indole also forms indolium, which allows electrophilic addition in acidic conditions, but current examples have been limited to intramolecular reactions. C2 site-selective nucleophilic addition to indole derivatives using fluoroalcohol and a Lewis acid was developed.
- Morimoto, Naoki,Morioku, Kumika,Suzuki, Hideyuki,Takeuchi, Yasuo,Nishina, Yuta
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supporting information
p. 2020 - 2023
(2016/06/01)
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- Rhodium-Catalyzed β-Selective Oxidative Heck-Type Coupling of Vinyl Acetate via C-H Activation
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An efficient Rh(III)-catalyzed direct ortho-C-H olefination of acetanilides with vinyl acetate was developed. This protocol provides a straightforward pathway to a series of (E)-2-acetamidostyryl acetates, giving access to indole derivatives following a simple hydrolysis/cyclization process.
- Zhang, Hui-Jun,Lin, Weidong,Su, Feng,Wen, Ting-Bin
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p. 6356 - 6359
(2016/12/23)
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- An efficient and green method for regio- and chemo-selective Friedel-Crafts acylations using a deep eutectic solvent ([CholineCl][ZnCl2]3)
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[CholineCl][ZnCl2]3, a deep eutectic solvent between choline chloride and ZnCl2, has been used as a dual function catalyst and green solvent for the Friedel-Crafts acylation of aromatic compounds instead of using the moisture-sensitive Lewis acids and volatile organic solvents. The reactions are performed with high yields under microwave irradiation with short reaction times for the synthesis of ketones. Interestingly, indole derivatives are regioselectively acylated in the 3-position under mild conditions with high yields without NH protection. Three new ketone products are synthesized. [CholineCl][ZnCl2]3 is easily synthesized from choline chloride and zinc chloride at a low cost, with easy purification and environmentally benign compounds. [CholineCl][ZnCl2]3 can be reused up to five times without loss of catalytic activity, making it ideal in industrial processes.
- Tran, Phuong Hoang,Nguyen, Hai Truong,Hansen, Poul Erik,Le, Thach Ngoc
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p. 37031 - 37038
(2016/05/24)
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- One-Step Dual Template Mediated Synthesis of Nanocrystalline Zeolites of Different Framework Structures
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A novel, dual template mediated, one-step direct synthesis route is reported here for the preparation of nanocrystalline zeolites of different framework structures (such as ZSM-5, mordenite, and sodalite). In this synthesis strategy, a suitably designed dicationic/tetra-cationic soft template was used along with a conventional zeolite structure director to obtain nanocrystalline zeolites with nanosheet morphology. Nanocrystalline zeolites exhibited large surface area, pore volume, and intercrystalline mesopores. The long hydrophobic chain containing a multiammonium template cooperatively participates in the zeolite crystallization process along with a conventional microporous zeolite structure director to form the ultrathin microporous zeolite framework, while the hydrophobic interaction between the long chains restricted the excessive growth of zeolites and induced the formation of intercrystalline mesopores. Nanocrystalline zeolites exhibited exceptionally high activity in the acid-catalyzed reactions involving large molecules when compared with conventional zeolites. This synthesis strategy can be extended for the preparation of zeolites of different framework structures or other porous materials in the future.
- Rani, Poonam,Srivastava, Rajendra,Satpati, Biswarup
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p. 3323 - 3333
(2016/06/14)
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- A Direct Access to 7-Aminoindoles via Iridium-Catalyzed Mild C-H Amidation of N-Pivaloylindoles with Organic Azides
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Ir(III)-catalyzed regioselective direct C-7 amidation of indoles in reaction with organic azides has been developed. While its efficiency was varied by the choice of N-directing groups, N-pivaloylindoles were most effective in undergoing the desired amidation at room temperature over a broad range of substrates. The reaction was scalable, and deprotection of the chelation group was also facile.
- Kim, Youyoung,Park, Juhyeon,Chang, Sukbok
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supporting information
p. 1892 - 1895
(2016/05/19)
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- Intermolecular dearomative C2-arylation of N-Ac indoles activated by FeCl3
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We report the FeCl3-mediated direct addition of electron-rich arenes to the C2-position of electrophilic N-Ac indoles under mild conditions (room temperature, air). No functional group is required on the arene nucleophile: one of its C-H bonds is added to the C2=C3 double bond of the indole nucleus in a Friedel-Crafts-type reaction. This dearomatisation process delivered a broad range of C2-arylated indolines.
- Nandi, Raj Kumar,Ratsch, Friederike,Beaud, Rodolphe,Guillot, Régis,Kouklovsky, Cyrille,Vincent, Guillaume
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p. 5328 - 5331
(2016/04/26)
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- Synthesis of industrially important aromatic and heterocyclic ketones using hierarchical ZSM-5 and Beta zeolites
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Hierarchical ZSM-5 and Beta zeolites were investigated in the synthesis of wide range of industrially important aromatic/heterocyclic ketones by Friedel-Crafts acylation and benzoylation reactions. For comparative study, conventional ZSM-5 and Beta, and amorphous mesoporous Al-MCM-41 were investigated. Hierarchical zeolites were prepared by multi-ammonium structure directing agents whereas conventional zeolites were prepared by mono-ammonium structure directing agents. Among the catalysts investigated in this study, hierarchical Beta exhibited the highest reactant conversion in the acylation and benzoylation reactions. In this study, the systematic assessment of the catalytic activity of acid catalysts for wide range of aromatic and heterocyclic compounds is shown under one umbrella. To the best of our knowledge, these reactions over hierarchical zeolites (ZSM-5 and Beta) are reported here for the first time. Structure activity relationship is explained based on the physico-chemical properties, molecular size, reactivity of reactants, and reaction mechanism. Catalysts can be easily recovered and reused with negligible loss in the catalytic activity.
- Kore, Rajkumar,Srivastava, Rajendra,Satpati, Biswarup
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p. 129 - 141
(2015/09/28)
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- Palladium-catalyzed intermolecular C-2 alkenylation of indoles using oxygen as the oxidant
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A general and efficient palladium-catalyzed intermolecular direct C-2 alkenylation of indoles using oxygen as the oxidant has been developed. The reaction is of complete regio- and stereoselectivity. All products are E-isomers at the C-2-position with no Z-isomers and 3-substituted products were detected.
- Yan, Zhao-Lei,Chen, Wen-Liang,Gao, Ya-Ru,Mao, Shuai,Zhang, Yan-Lei,Wang, Yong-Qiang
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supporting information
p. 1085 - 1092
(2014/04/03)
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- Synthetic approaches to 3,3'-biindolyl and 3,3'-biindazolyl derivatives
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In this paper new syntheses of 3,3'-biindolyl and 3,3'-biindazolyl derivatives are described. Formation of 3,3'-biindolyl derivatives by oxidative coupling of N-acetylindole with TeCl4 gave a good yield, while attempt to use the same reaction conditions for synthesis of 3,3'-biindazolyl derivatives failed. However, conversion of 3-haloindazole derivatives to its trimethylstannane derivative, followed by palladium-catalyzed Stille cross-coupling reaction, resulted in formation of 3,3'-biindazolyl derivatives.
- Nakhai, Azadeh,Bergman, Jan
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p. 309 - 318
(2014/01/17)
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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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- Dehydroaromatization with V2O5
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Vanadium pentoxide is evaluated as a dehydroaromatization reagent. Tetrahydrocarbazole is readily aromatized by V2O5 in refluxing acetic acid under both stoichiometric and catalytic conditions. Indoline, tetrahydroquinoline, and tetrahydroquinoxaline are effectively aromatized by V2O5/silica in refluxing toluene. Georg Thieme Verlag Stuttgart New York.
- Karki, Megha,Araujo, Hugoc.,Magolan, Jakob
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p. 1675 - 1678
(2013/09/02)
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- A trans diacyloxylation of indoles
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A trans diacyloxylation of indoles is accomplished by employing PhI(OAc)2 as the oxidant. A broad range of functional groups are well tolerated. Both the electronic properties of the N-protecting groups of indoles and the acidity of the reaction media play important roles in the selectivity of indole acyloxylation reactions. The Royal Society of Chemistry 2012.
- Liu, Qiang,Zhao, Qing Yong,Liu, Jie,Wu, Pan,Yi, Hong,Lei, Aiwen
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supporting information; experimental part
p. 3239 - 3241
(2012/04/10)
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- Microwave-assisted Friedel-Crafts acylation of indole with acetic anhydride over tungstophosphoric acid modified Hβ zeolite
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Friedel-Crafts acylation of indole with acetic anhydride has been carried out over zeolites under microwave and conventional heating, respectively. A tungstophosphoric acid modified Hβ (PW-Hβ) zeolite showed better catalytic performance than parent Hβ zeolite due to its higher amount of strongly acidic sites and lower amount of Lewis acid sites, confirmed from NH3 temperature-programmed desorption (NH3-TPD) and Fourier Transform Infrared Spectrometer after adsorption of pyridine (Py-IR). Particularly, microwave radiation was found to make this transformation not only more efficient but also selective to 3-acetylindole compared with conventional heating. Furthermore, PW-Hβ has shown good stability in this reaction.
- Bai, Guoyi,Li, Tianyu,Yang, Yonghui,Zhang, Huanhuan,Lan, Xingwang,Li, Fei,Han, Jie,Ma, Zheng,Chen, Qingzhi,Chen, Guofeng
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p. 114 - 117
(2013/01/15)
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- Ir(I)-catalyzed C-H bond alkylation of C2-position of indole with alkenes: Selective synthesis of linear or branched 2-alkylindoles
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A cationic iridium-catalyzed C2-alkylation of N-substituted indole derivatives with various alkenes has been developed, which selectively gives linear or branched 2-alkylindoles in high to excellent selectivity. This protocol relies on the use of the carbonyl group on the nitrogen atom of indole as a directing group: a linear product was predominant when an acetyl group was used as a directing group, and a branched product was predominant with a benzoyl group.
- Pan, Shiguang,Ryu, Naoto,Shibata, Takanori
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p. 17474 - 17477,4
(2012/12/12)
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- Ir(I)-catalyzed C-H bond alkylation of C2-position of indole with alkenes: Selective synthesis of linear or branched 2-alkylindoles
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A cationic iridium-catalyzed C2-alkylation of N-substituted indole derivatives with various alkenes has been developed, which selectively gives linear or branched 2-alkylindoles in high to excellent selectivity. This protocol relies on the use of the carbonyl group on the nitrogen atom of indole as a directing group: a linear product was predominant when an acetyl group was used as a directing group, and a branched product was predominant with a benzoyl group.
- Pan, Shiguang,Ryu, Naoto,Shibata, Takanori
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p. 17474 - 17477
(2013/01/15)
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- Replacing conventional carbon nucleophiles with electrophiles: Nickel-catalyzed reductive alkylation of aryl bromides and chlorides
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A general method is presented for the synthesis of alkylated arenes by the chemoselective combination of two electrophilic carbons. Under the optimized conditions, a variety of aryl and vinyl bromides are reductively coupled with alkyl bromides in high yields. Under similar conditions, activated aryl chlorides can also be coupled with bromoalkanes. The protocols are highly functional-group tolerant (-OH, -NHTs, -OAc, -OTs, -OTf, -COMe, -NHBoc, -NHCbz, -CN, -SO2Me), and the reactions are assembled on the benchtop with no special precautions to exclude air or moisture. The reaction displays different chemoselectivity than conventional cross-coupling reactions, such as the Suzuki-Miyaura, Stille, and Hiyama-Denmark reactions. Substrates bearing both an electrophilic and nucleophilic carbon result in selective coupling at the electrophilic carbon (R-X) and no reaction at the nucleophilic carbon (R-[M]) for organoboron (-Bpin), organotin (-SnMe3), and organosilicon (-SiMe2OH) containing organic halides (X-R-[M]). A Hammett study showed a linear correlation of σ and σ(-) parameters with the relative rate of reaction of substituted aryl bromides with bromoalkanes. The small ρ values for these correlations (1.2-1.7) indicate that oxidative addition of the bromoarene is not the turnover-frequency determining step. The rate of reaction has a positive dependence on the concentration of alkyl bromide and catalyst, no dependence upon the amount of zinc (reducing agent), and an inverse dependence upon aryl halide concentration. These results and studies with an organic reductant (TDAE) argue against the intermediacy of organozinc reagents.
- Everson, Daniel A.,Jones, Brittany A.,Weix, Daniel J.
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supporting information; experimental part
p. 6146 - 6159
(2012/05/07)
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- Enantioselective cyclopropanation of indoles: Construction of all-carbon quaternary stereocenters
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The first enantioselective copper-catalyzed cyclopropanation of N-acyl indoles is described. Using carbohydrate-based bis(oxazoline) ligands (glucoBox), the products were obtained in up to 72% ee. Cyclopropanation of N-Boc 3-methyl indole yielded a product with an all-carbon quaternary stereocenter, which is a valuable building block for the synthesis of indole alkaloids: Deprotection and rearrangement gave a tricyclic hemiaminal ester in 96% ee, which was subsequently employed as a key intermediate for the synthesis of (-)-desoxyeseroline.
- ?züduru, Gülsüm,Schubach, Thea,Boysen, Mike M. K.
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supporting information
p. 4990 - 4993
(2013/01/15)
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- Thermally decomposed Ni-Fe-hydrotalcite: A highly active catalyst for the solvent-free N-acylation of different amines by acid chlorides
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A composite Ni-Fe catalyst obtained from the thermal decomposition of Ni-Fe-hydrotalcite at 600 °C shows very high activity in the solvent-free N-acylation of amines by different acid chlorides with high product yields under very mild reaction conditions (viz. room temperature, short reaction period and small amount of catalyst). The catalyst also shows excellent reusability in the reaction. The crystalline phases present in the catalyst are mixed oxides and hydroxides of nickel and iron. The high catalytic activity of the decomposed Ni-Fe-hydrotalcite is attributed to the formation of uniformly distributed Ni-Fe metal oxides and hydroxides.
- Choudhary,Dumbre
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experimental part
p. 1351 - 1356
(2012/01/06)
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- Tunable hydride transfer in the redox amination of indoline with aldehyde: An attractive intramolecular hydrogen-bond effect
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Hydride hijacked by "hydrogen"! N-Alkylindoles and N-alkylindolines were obtained in the redox amination of indoline with aldehyde, which was tuned by a hydrogen-bond effect. Salicylaldehyde gave the indoline-type product via intermolecular hydride transfer, while other aromatic aldehydes gave the indole-type product via intramolecular hydride transfer. Copyright
- Mao, Hui,Xu, Runsheng,Wan, Jieping,Jiang, Zhengyang,Sun, Cuirong,Pan, Yuanjiang
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supporting information; experimental part
p. 13352 - 13355
(2011/03/17)
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- Oxaziridine-mediated oxyamination of indoles: An approach to 3-aminoindoles and enantiomerically enriched 3-aminopyrroloindolines
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A radical solution: A highly regioselective copper(II)-catalyzed oxyamination of N-acyl indoles with oxaziridines gave aminal products that could be converted in a single step into 3-aminoindoles and 3-aminopyrroloindolines (see scheme). When a chiral N-acyl group was used, the core fragment of some architecturally fascinating pyrroloindoline alkaloids was formed with 91% ee. Bs=benzenesulfonyl, Moc=methoxycarbonyl. Copyright
- Benkovics, Tamas,Guzei, Ilia A.,Yoon, Tehshik P.
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supporting information; experimental part
p. 9153 - 9157
(2011/02/19)
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- NOVEL INDOLIC DERIVATIVES, THEIR PREPARATION PROCESSES AND THEIR USES IN PARTICULAR AS ANTIBACTERIALS
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The invention relates to the use of at least one compound of the formula (I), in which R and R3 are particularly a hydrogen atom, R1 is particularly a hydrogen atom or a methyl, ethyl or isobutyl mi group, R4, R5, R6 and R7 are independently a hydrogen atony, an alkoxyl group with 1 to 7 carbon atoms or a halogen atom, R2 is a hydrogen atom, an O? group or an OH group, B is an N-GP1 or NRc, group, GP1 being a Boc or Cbz group, and Rc is a hydrogen atom or a methyl or t-butyl group, for preparing a drug for treating conditions associated with bacterial infections, in particular for treating bacterial diseases.
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Page/Page column 46
(2010/06/19)
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- Mild and useful method for n-acylation of amines
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Iodine is found to promote quantitative N-acylation of primary and secondary amines (aliphatic and aromatic) in a very short time with an equimolar amount of acetyl chloride and benzoyl chloride under solvent-free conditions at room temperature. This catalytic acylation of amines offers an additional useful method for the acetylation using acetyl chloride instead of acetic anhydride and other acetylating agents. This method is also useful in the N-acylation of heterocycles. Mild reaction condition, high selectivity, efficiency, and good yields are some of the major advantages of the procedure.
- Phukan, Kandarpa,Ganguly, Mausumi,Devi, Nirada
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experimental part
p. 2694 - 2701
(2009/12/06)
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- A new, stereoselective, ring-forming reaction of 1,2-ethanedithiol with N-acylated indoles
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(Chemical Equation Presented) While attempting to prepare 2,5-dithiacyclopentyl derivatives from N-acyl 5-fluoroindole by reaction with 1,2-ethanedithiol we discovered that, instead of the expected product, annelation occurred to give a tricyclic compound containing a 3,6-dithiaazepine ring. This reaction is stereoselective and was found to be general for N-acylindoles, not being affected by substituents on the indole ring.
- Tsotinis, Andrew,Eleutheriades, Andreas,Di Bari, Lorenzo,Pescitelli, Gennaro
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p. 8928 - 8931
(2008/03/12)
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- Development of isomerization and cycloisomerization with use of a ruthenium hydride with N-heterocyclic carbene and its application to the synthesis of heterocycles
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A pure ruthenium hydride complex with N-heterocyclic carbene (NHC) ligand was efficiently generated from the reaction of a second-generation Grubbs ruthenium catalyst with vinyloxytrimethylsilane and unambiguously characterized. This ruthenium hydride complex showed high catalytic activity for the selective isomerization of terminal olefin and for the cycloisomerization of 1,6-dienes. These reactions of N-allyl-o-vinylaniline lead to novel synthetic methods for heterocycles such as indoles and 3-methylene-2,3-dihydroindoles, which are useful synthons for bioactive natural products. These procedures address an important issue in diversity-oriented synthesis.
- Arisawa, Mitsuhiro,Terada, Yukiyoshi,Takahashi, Kazuyuki,Nakagawa, Masako,Nishida, Atsushi
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p. 4255 - 4261
(2007/10/03)
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- Amberlyst-15 catalyzed acetylation of heteroaromatics with acetic anhydride under solvent free conditions
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Amberlyst-15 has been found to be an efficient reusable heterogeneous catalyst for acetylation of indole, 2-methylindole and pyrrole with acetic anhydride under solvent free conditions.
- Das, Biswanath,Pal, Rammohan,Banerjee, Joydeep,Mahender,Holla, Harish,Venkateswarlu
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p. 198 - 200
(2007/10/03)
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- Cyclization of acetylenic amides using a cationic rhodium(I) complex
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The cationic Rh(I) dicarbonyl complex [{Rh(bim)(CO)2} +BPh4-] 1, containing a bidentate bisimidazolylmethane ligand [bim refers to bis(N-methylimidazol-2-yl)methane] acts as a catalyst for the cyclization of alkynyl amides to produce lactams and N-acyl heterocyclic compounds.
- Burling, Suzanne,Field, Leslie D.,Li, Hsiu L.,Messerle, Barbara A.,Shasha, Adelle
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p. 677 - 680
(2007/10/03)
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- Selective isomerization of a terminal olefin catalyzed by a ruthenium complex: The synthesis of indoles through ring-closing metathesis
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Aruthenium complex, generated from the Grubbs carbene catalyst with vinyloxytrimethylsilane, catalyzed the isomerization of terminal alkenes RCH2-CH=CH2 to internal alkenes RCH=CH-CH3. Application of this olefin isomerization to 2-(N-allylamino)styrene gave the corresponding enamines, which were converted into indoles by a standard ring-closing metathesis, see scheme (Ts = tosyl).
- Arisawa, Mitsuhiro,Terada, Yukiyoshi,Nakagawa, Masako,Nishida, Atsushi
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p. 4732 - 4734
(2007/10/03)
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- Generation and reactivity of 1,2-dilithioindole
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The generation of a 1,2-dianion (1) from 2-iodoindole is described. This dianion reacts at the carbanionic center with a range of electrophiles to give 2-substituted indoles in good yields.
- Herbert, John M.,Maggiani, Maria
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p. 947 - 951
(2007/10/03)
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- An efficient synthetic method for 2-methoxy-1,2-dihydro-3H-indol-3-ones
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An efficient method for synthesis of 2-methoxy-1,2-dihydro-3H-indol-3- ones using two successive oxidations of indoles is described.
- Kawasaki, Tomomi,Nonaka, Yoshinori,Matsumura, Ken,Monai, Miyuki,Sakamoto, Masanori
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p. 3251 - 3261
(2007/10/03)
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