- Formal Aza-Diels?Alder Reactions of Spiroindolenines with Electronrich Dienes
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Spiroindolenines were employed as cyclic imine substrates in formal aza-Diels?Alder reactions with Danishefsky's diene or silyloxy-substituted electron-rich dienes for the synthesis of the corresponding tetrahydropyrido[1,2-a]spiroindolinones. The reactions occur under mild conditions in the presence of ytterbium triflate as Lewis acidic catalyst delivering the desired compounds in good yield. The reaction results in the preparation of a small library of a new class of conformational constrained heterocyclic derivatives that easily undergo selective and efficient manipulations.
- Brambilla, Elisa,Leoni, Sara,Abbiati, Giorgio,Pirovano, Valentina,Rossi, Elisabetta
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- Novel tetrahydrocarbazole benzyl pyridine hybrids as potent and selective butryl cholinesterase inhibitors with neuroprotective and β-secretase inhibition activities
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Butyrylcholinesterase (BuChE) inhibitors have become interesting target for treatment of Alzheimer's disease (AD). A series of dual binding site BuChE inhibitors were designed and synthesized based on 2,3,4,9-tetrahydro-1H-carbazole attached benzyl pyridine moieties. In-vitro assay revealed that all of the designed compounds were selective and potent BuChE inhibitors. The most potent BuChE inhibitor was compound 6i (IC50 = 0.088 ± 0.0009 μM) with the mixed-type inhibition. Docking study revealed that 6i is a dual binding site BuChE inhibitor. Also, Pharmacokinetic properties for 6i were accurate to Lipinski's rule. In addition, compound 6i demonstrated neuroprotective and β-secretase (BACE1) inhibition activities. This compound could also inhibit AChE-induced and self-induced Aβ peptide aggregation at concentration of 100 μM and 10 μM respectively. Generally, the results are presented as new potent selective BuChE inhibitors with a therapeutic potential for the treatment of AD.
- Ghobadian, Roshanak,Mahdavi, Mohammad,Nadri, Hamid,Moradi, Alireza,Edraki, Najmeh,Akbarzadeh, Tahmineh,Sharifzadeh, Mohammad,Bukhari, Syed Nasir Abbas,Amini, Mohsen
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- 13C NMR Chemical Shift Assignments for Some Carbazole Derivatives
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13C NMR chemical shift assignments have been made for a series of 1-substituted carbazoles, 8-substituted 1,2,3,4-tetrahydrocarbazoles, 1-substituted benzocarbazoles and 6-substituted dibenzocarbazoles.Single examples were examined of other classes of substituted carbazoles: 3-butylcarbazole and its tetrahydro precursor 6-butyl-1,2,3,4-tetrahydrocarbazole, 8-butyl- and 8,10-diethylbenzocarbazoles and their 5,6-dihydro precursors, dibenzocarbazole and its 5,6,7,8-tetrahydro precursor, benzocarbazole and its 6-chloro derivatives and 5,6-dihydrobenzocarbazole and 5,6,8,9-tetrahydrodibenzocarbazole and their N-methyl derivatives.In addition, the N-(1-pyrrolidinomethyl) derivatives of carbazole, 1,2,3,4-tetrahydrocarbazole, benzocarbazole and dibenzocarbazole were also studied.KEY WORDS 13C NMR Chemical shift assignments Carbazole derivatives.
- Katritzky, Alan R.,Rewcastle, Gordon W.,Miguel, Luis M. Vazquez de,Wang, Zuoquan
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- Fischer indole synthesis over hydrous zirconia-supported niobium oxide
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Supported niobium oxides are investigated as green catalysts for Fischer indole reaction. By means of wet impregnation, 1040 wt-% Nb2O 5 were loaded onto hydrous zirconia as a support. Pore size distribution curves showed that the niobium oxide overlayer was uniformly dispersed onto the mesoporous support. Samples with close to a monolayer coverage of niobium oxide had the highest activity in the Fischer indole reaction of phenylhydrazine with both 3-heptanone and cyclohexanone. A coverage higher than a monolayer led to lower activity. In comparison, the supported catalysts were more active than bulk niobium oxide or a sample prepared by co-precipitation of hydrous zirconia and niobium oxide. CSIRO 2009.
- Zhong, Liang,Chuah, Gaik-Khuan
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- Process for synthesizing [b]-cycloindole derivatives
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The invention discloses a method for synthesizing [b]-cyclized indole derivatives. The method comprises the steps as follows: alkylation ring-closing domino reactions at C2 and C3 sites of indole aresequentially realized with a one-pot process under the action of alkali and a palladium catalyst with norbornene as a transient guide medium and dihaloalkane as an alkylation reagent, and the [b]-cyclized indole derivatives are effectively synthesized. The method has mild conditions, commercially available indole is directly used as a substrate, a pre-functionalization process is omitted, reactionsteps are reduced, the atom economy is higher, simple indole micromolecular structures are modified, and the [b]-cyclized indole derivatives can be further applied to medicine or total synthesis research and the like and have higher potential value and broad application prospects in medicinal chemistry and other fields.
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Paragraph 0033-0035
(2021/04/17)
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- Iron-Catalyzed Radical Activation Mechanism for Denitrogenative Rearrangement Over C(sp3)–H Amination
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An iron-catalyzed denitrogenative rearrangement of 1,2,3,4-tetrazole is developed over the competitive C(sp3)–H amination. This catalytic rearrangement reaction follows an unprecedented metalloradical activation mechanism. Employing the developed method, a wide number of complex-N-heterocyclic product classes have been accessed. The synthetic utility of this radical activation method is showcased with the short synthesis of a bioactive molecule. Collectively, this discovery underlines the progress of radical activation strategy that should find wide application in the perspective of medicinal chemistry, drug discovery and natural product synthesis research.
- Roy, Satyajit,Das, Sandip Kumar,Khatua, Hillol,Das, Subrata,Singh, Krishna Nand,Chattopadhyay, Buddhadeb
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p. 8772 - 8780
(2021/03/16)
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- Tetrahydrocarbazoles by mechanochemical Fischer indolisation
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The Fischer indolisation (FI) typically proceeds in the presence of a Br?nsted or Lewis acid in an organic solvent at elevated temperatures. Herein, we report that tetrahydrocarbazoles (THCs) are accessible by mechanochemical FI at ambient temperature. Using phenylhydrazine hydrochlorides in the presence of silica is critical for this solid-state variant of the FI.
- Qiu, Yichen,Puni, Kararaina Te,Duplan, Clotilde C.,Lindsay, Ashley C.,Sperry, Jonathan
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supporting information
(2021/05/26)
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- Palladium-catalyzed dearomative allylation of indoles with cyclopropyl acetylenes: access to indolenine derivatives
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A palladium-catalyzed redox-neutral allylic alkylation of indoles with cyclopropyl acetylenes has been disclosed. Various 1,3-diene indolenine framework bearing a quaternary stereocenter at the C3 position were synthesized straightforwardly in good to excellent yields with high regio- and stereoselectivities. The reaction could be further expanded to the dearomatization of naphthols to synthesize functionalized cyclohexadienones with 1,3-diene motifs. The reaction exhibited high atom economy and good functional group tolerance.
- Lu, Chuan-Jun,Chen, Yu-Ting,Wang, Hong,Li, Yu-Jin
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p. 635 - 644
(2021/02/06)
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- One-pot, three-component Fischer indolisation-N-alkylation for rapid synthesis of 1,2,3-trisubstituted indoles
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A one-pot, three-component protocol for the synthesis of 1,2,3-trisubstituted indoles has been developed, based upon a Fischer indolisation-indoleN-alkylation sequence. This procedure is very rapid (total reaction time under 30 minutes), operationally straightforward, generally high yielding and draws upon readily available building blocks (aryl hydrazines, ketones, alkyl halides) to generate densely substituted indole products. We have demonstrated the utility of this process in the synthesis of 23 indoles, benzoindoles and tetrahydrocarbazoles bearing varied and useful functionality.
- Hughes-Whiffing, Christopher A.,Perry, Alexis
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supporting information
p. 627 - 634
(2021/02/06)
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- Synthesis of indoles through acceptorless dehydrogenative coupling catalyzed by nickel on silica-alumina
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The high atom-economical formation of indoles from anilines and diols was described with affordable and easy to handle Ni/SiO2-Al2O3. After optimization, 2,3-dimethylindole was isolated with an excellent 98% yield in neat conditions. The scope of the reaction was studied and 13 indoles were isolated in 16–80% yields.
- Charvieux, Aubin,Hammoud, Abdul Aziz,Duclos, Marie-Christine,Duguet, Nicolas,Métay, Estelle
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supporting information
(2021/07/25)
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- Acceptorless dehydrogenative condensation: synthesis of indoles and quinolines from diols and anilines
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The use of diols and anilines as reagents for the preparation of indoles represents a challenge in organic synthesis. By means of acceptorless dehydrogenative condensation, heterocycles, such as indoles, can be obtained. Herein we present an experimental and theoretical study for this purpose employing heterogeneous catalysts Pt/Al2O3and ZnO in combination with an acid catalyst (p-TSA) and NMP as solvent. Under our optimized conditions, the diol excess has been reduced down to 2 equivalents. This represents a major advance, and allows the use of other diols. 2,3-Butanediol or 1,2-cyclohexanediol has been employed affording 2,3-dimethyl indoles and tetrahydrocarbazoles. In addition, 1,3-propanediol has been employed to prepare quinolines or natural and synthetic julolidines.
- Bellezza, Delia,Zaragozá, Ramón J.,José Aurell,Ballesteros, Rafael,Ballesteros-Garrido, Rafael
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supporting information
p. 677 - 683
(2021/02/06)
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- Synthesis and evaluation of 2,3,4,9-tetrahydro-1H-carbazole derivatives as selective acetylcholinesterase inhibitors: Potential anti-Alzheimer's agents
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Alzheimer's disease is an irreversible, progressive brain disorder that slowly destroys memory and cognition skills. Dysfunction of acetylcholine containing neurons in the brain contributes substantially to the cognitive decline observed in Alzheimer's disease. Hence, our focus is to synthesize cholinesterase inhibitors. A series (22 compounds) of 6- and 9-substituted derivatives of 2,3,4,9-tetrahydro-1H-carbazole have been prepared and in vitro evaluated for acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibition by Ellman's method. By comparing selectivity with standard drug donepezil, amino derivative 3, methylamino derivative 4 and butyl nitro derivative 17 have been found to be selective AChE inhibitors. Borsche-Drechsel cyclization reaction has been carried out to synthesize 2,3,4,9-tetrahydrocarbazole ring followed by nitration, reduction and derivative synthesis.
- Chopra, Dimple Sethi,Chugh, Rajan,Kukreja, Hitesh,Shah, Ramanpreet,Singh, Dhandeep,Singh, Jatinder,Singh, Mandeep,Singh, Nirmal
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p. 152 - 160
(2021/09/28)
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- Direct Synthesis of Indoles from Azoarenes and Ketones with Bis(neopentylglycolato)diboron Using 4,4′-Bipyridyl as an Organocatalyst
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Multifunctionalized indole derivatives were prepared by reducing azoarenes in the presence of ketones and bis(neopentylglycolato)diboron (B2nep2) with a catalytic amount of 4,4′-bipyridyl under neutral reaction conditions, where 4,4′-bipyridyl acted as an organocatalyst to activate the B-B bond of B2nep2 and form N,N′-diboryl-1,2-diarylhydrazines as key intermediates. Further reaction of N,N′-diboryl-1,2-diarylhydrazines with ketones afforded N-vinyl-1,2-diarylhydrazines, which rearranged to the corresponding indoles via the Fischer indole mechanism. This organocatalytic system was applied to diverse alkyl cyclic ketones, dialkyl, and alkyl/aryl ketones, including heteroatoms. Methyl alkyl ketones gave the corresponding 2-methyl-3-substituted indoles in a regioselective manner. This protocol allowed us to expand the preparation of indoles having high compatibility with not only electron-donating and electron-withdrawing groups but also N- and O-protecting functional groups.
- Misal Castro, Luis C.,Sultan, Ibrahim,Nishi, Kohei,Tsurugi, Hayato,Mashima, Kazushi
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p. 3287 - 3299
(2021/03/01)
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- Visible-light-driven Cadogan reaction
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Visible-light-driven photochemical Cadogan-type cyclization has been discovered. The organic D-A type photosensitizer 4CzIPN found to be an efficient mediator to transfer energy from photons to the transient intermediate that breaks the barriers of deoxygenation in Cadogan reaction and enables a mild metal-free access to carbazoles and related heterocycles. DFT calculation results indicate mildly endergonic formation of the intermediate complex of nitrobiarenes and PPh3, which corresponds with experimental findings regarding reaction temperature. The robust synthetic capacity of the photoredox Cadogan reaction systems has been demonstrated by the viable productivity of a broad range of carbazoles and related N-heterocycles with good tolerance of various functionalities.
- Qu, Zhonghua,Wang, Pu,Chen, Xing,Deng, Guo-Jun,Huang, Huawen
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p. 2582 - 2586
(2021/03/09)
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- A palladium-catalyzed Barluenga cross-coupling – Reductive cyclization sequence to substituted indoles
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A short and flexible synthesis of substituted indoles employing two palladium-catalyzed reactions, a Barluenga cross-coupling of p-tosylhydrazones with 2-nitroarylhalides followed by a palladium–catalyzed, carbon monoxide–mediated reductive cyclization has been developed. A one-pot, two-step methodology was further developed, eliminating isolation and purification of the cross-coupling product. This was accomplished by utilizing the initially added 0.025 equivalents of bis(triphenylphosphine)palladium dichloride, thus serving a dual role in the cross-coupling and the reductive cyclization. It was found that addition of 1,3-bis(diphenylphosphino)propane and carbon monoxide after completion of the Barluenga reaction afforded, in most cases, significantly better overall yields.
- Rahman, S. M. Ashikur,S?derberg, Bj?rn C. G.
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- Switching Chemoselectivity Based on the Ring Size: How to Make Ring-Fused Indoles Using Transition-Metal-Mediated Cross-Coupling
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Pyrroloazocine indole alkaloids consisting of eight-membered azacycle fused to pyrrole and indole units exhibit intriguing pharmacological functions but still pose a synthetic challenge. Here, we report an alternative synthetic strategy for the pyrroloazocine indole core from two key steps: (i) regioselective Fischer indolization and (ii) transition-metal-mediated C-N cross-coupling reaction ofN-Boc aryl hydrazine with azacyclic vinyl triflate. In our investigation, Pd(0)- and Cu(I)-catalysts are found to display distinct and complementary selectivities for the ring size of cyclic vinyl triflates. For rings that are five- and six-membered, a Pd(0)-catalyst afforded the corresponding ene-hydrazines while completely ineffective for seven-membered or larger rings. A Cu(I)-catalyst exhibited the opposite selectivities. Computational studies reveal that their ring size dependency is due to the two bottlenecks of reductive elimination for Pd and oxidative addition for Cu along with bond strengths in products and reactants and degree of stage at transition states. These findings led us to establish a straightforward protocol for accessing a variety of ring-fused indoles highlighted with the formal synthesis of (?)-lundurine A.
- Baik, Mu-Hyun,Cho, Cheon-Gyu,Jeon, Tae-Hong,Kang, Hyung-Joon,Kim, Jang-Yeop,Lee, Woojong
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p. 12821 - 12832
(2021/10/29)
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- Copper-catalyzed tri- or tetrafunctionalization of alkenylboronic acids to prepare tetrahydrocarbazol-1-ones and indolo[2,3-a]carbazoles
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We describe a cascade strategy for tri- or tetrafunctionalization of alkenylboronic acids to prepare diverse tetrahydrocarbazol-1-ones and indolo[2,3-a]carbazoles in good yields withN-hydroxybenzotriazin-4-one (HOOBT) and arylhydrazines as oxygen and nitrogen sources, respectively. Mechanistic studies reveal that the domino reaction undergoes the copper-catalyzed Chan-Lam reaction, [2,3]-rearrangement, nucleophilic substitution, oxidation and sequential [3,3]-rearrangement over five steps in a one-pot reaction. The reaction shows a broad substrate scope and tolerates a wide range of functional groups. More importantly, the reaction is easily performed at gram scales and the product is purified by simple extraction, washing, and recrystallization without flash column chromatography. The present protocol features easily available starting materials, high site-marked functionalization, five-step cascade in one pot, multiple C-C/C-O/C-N bond formation, and diversity of indole motifs.
- Bi, Hong-Yan,Li, Cheng-Jing,Liang, Cui,Mo, Dong-Liang,Wei, Cui
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p. 5815 - 5821
(2020/09/21)
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- Annulation of Indoles with 1,n-Dibromoalkanes by a Pd(II)-Catalyzed and Norbornene-Mediated Reaction Cascade
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Employing 1,3-dibromopropane, 1,4-dibromobutane, and 1,5-dibromopentane as biselectrophiles, the annulation of indoles was probed in the presence of PdCl 2 (MeCN) 2 as a catalyst and norbornene as a transpositional ligand. Ring formation to a five-membered ring was observed at positions C2 and N, while annulation of a six-membered ring occurred at positions C2 and C3. The latter cascade process was successfully applied to the direct synthesis of 1,2,3,4-tetrahydrocarbazoles from indoles (11 examples, 31-68% yield). Seven-membered-ring annulation was feasible by an initial coupling at positon C2 followed by alkylation at C3.
- Bach, Thorsten,Henkel, Michael
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p. 1231 - 1238
(2020/04/15)
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- Design, synthesis, in vivo and in vitro studies of 1,2,3,4-tetrahydro-9H-carbazole derivatives, highly selective and potent butyrylcholinesterase inhibitors
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Abstract: Inhibition of butyrylcholinesterase (BChE) might be a useful therapeutic target for Alzheimer’s disease (AD). A new series of 1,2,3,4-tetrahydro-9H-carbazole derivatives were designed synthesized and evaluated as BChE inhibitors. While all of the derivatives have shown for AChE IC50 values below the detectable limit (> 100?μM), they were selective potent BChE inhibitors. 1-(2-(6-fluoro-1,2,3,4-tetrahydro-9H-carbazole-9-yl)ethyl)piperidin-1-ium chloride (15?g) had the most potent anti-BChE activity (IC50 value = 0.11?μM), the highest BChE selectivity and mixed-type inhibition. Pharmacokinetic properties were accordant to Lipinski rule and compound 15g demonstrated neuroprotective and inhibition of β-secretase (BACE1) activities. Furthermore, in vivo study of compound 15g in Morris water maze task has confirmed memory improvement in scopolamine-induced impairment. All results suggest that new sets of potent selective inhibitors of BChE have a therapeutic potential for the treatment of AD. Graphical abstract: A new series of 1,2,3,4-tetrahydro-9H-carbazole derivatives were designed synthesized and evaluated as BChE inhibitors. While all of the derivatives have shown for AChE IC50 values below the detectable limit, they were selective potent BChE inhibitors. Compound 15g had the most potent anti-BChE activity. All results suggest that new sets of potent selective inhibitors of BChE have a therapeutic potential for the treatment of AD.[Figure not available: see fulltext.]
- Ghobadian, Roshanak,Esfandyari, Roghaieh,Nadri, Hamid,Moradi, Alireza,Mahdavi, Mohammad,Akbarzadeh, Tahmineh,Khaleghzadeh-Ahangar, Hossein,Edraki, Najmeh,Sharifzadeh, Mohammad,Amini, Mohsen
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p. 211 - 223
(2019/04/17)
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- Carbazole based Electron Donor Acceptor (EDA) catalysis for the synthesis of biaryl and aryl-heteroaryl compounds
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A highly regioselective, carbazole based Electron Donor Acceptor (EDA) catalyzed synthesis of biaryl and aryl-heteroaryl compounds is described. Various indole and carbazole derivatives were screened for the Homolytic Aromatic Substitution (HAS) reaction. Tetrahydrocarbazole (THC) was very efficient for the HAS transformation and proceeded via a complex formation between diazonium salt and electron rich tetrahydrocarbazole. The UV-Vis spectroscopy technique has been used to confirm the complex formation. The in situ generated EDA complex even in a catalytic amount is found to be efficient for the Single Electron Transfer (SET) process without any photoactivation. Biaryl compounds, 2-phenylfuran, 2-phenylthiophene, and 2-phenylpyrrole and bioactive compounds such as dantrolene and canagliflozin have been synthesized in moderate to excellent yields.
- Annes, Sesuraj Babiola,Ramesh, Subburethinam,Saravanan, Subramanian,Saritha, Rajendhiran
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supporting information
p. 2510 - 2515
(2020/04/15)
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- Palladium-Catalyzed Amination/Dearomatization Reaction of Indoles and Benzofurans
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This report describes a palladium-catalyzed dearomatization and amination tandem reaction of 2,3-disubstituted indoles and benzofurans via the Catellani strategy. This reaction provides a new method for the construction of amino-substituted indoline-fused cyclic and benzofuran spiro compounds in good yields. The reaction has broad functional group compatibility and substrate scope.
- Zhang, Zhe,Zhang, Bo-Sheng,Li, Kai-Li,An, Yang,Liu, Ce,Gou, Xue-Ya,Liang, Yong-Min
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p. 7817 - 7839
(2020/07/16)
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- A NaH-promoted N-detosylation reaction of diverse p-toluenesulfonamides
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A NaH-mediated detosylation reaction of various Ts-protected indoles, azaheterocycles, anilines and dibenzylamine was reported. The method features cheap reagent, convenient operations, mild reaction conditions and broad substrate scope. Moreover, this study revealed that the loading of NaH in tosylation reactions of nitrogen-containing compounds with NaH as a base in DMA or DMF should be controlled due to the possibility of adverse detosylation.
- Sun, Wanwan,Chen, Xiaobei,Hu, Ying,Geng, Huihui,Jiang, Yuanrui,Zhou, Yuxin,Zhu, Wenjing,Hu, Min,Hu, Haohua,Wang, Xingyi,Wang, Xinli,Zhang, Shilei,Hu, Yanwei
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supporting information
(2020/10/05)
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- SBA-15-Pr-SO3H catalyzed one-pot synthesis of indole derivatives via Fischer indole pathway
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In this work, an efficient, user-friendly, and simple procedure was reported for the preparation of indole derivatives catalyzed by the heterogeneous SBA-15-Pr-SO3H via Fischer indole pathway. The title compounds were synthesized from various arylhydrazines and ketones in the presence of 3 mol% of the catalyst in the refluxing ethanol.
- Ghiyasabadi, Zahra,Bahadorikhalili, Saeed,Saeedi, Mina,Karimi-Niyazagheh, Mona,Mirfazli, Seyedeh Sara
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supporting information
p. 606 - 610
(2020/01/03)
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- Soluble asphaltene oxide: A homogeneous carbocatalyst that promotes synthetic transformations
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Carbocatalysts, materials which are predominantly composed of carbon and catalyze the synthesis of organic or inorganic compounds, are promising alternatives to metal-based analogues. Even though current carbocatalysts have been successfully employed in a broad range of synthetic transformations, they suffer from a number of drawbacks in part due to their heterogeneous nature. For example, the insolubility of prototypical carbocatalysts, such as graphene oxide (GO), may restrict access to catalytically-active sites in a manner that limits performance and/or challenges optimization. Herein we describe the preparation and utilization of soluble asphaltene oxide (sAO), which is a novel material that is composed of oxidized polycyclic aromatic hydrocarbons and is soluble in a wide range of organic solvents as well as in aqueous media. sAO promotes an array of synthetically useful transformations, including esterifications, cyclizations, multicomponent reactions, and cationic polymerizations. In many cases, sAO was found to exhibit higher catalytic activities than its heterogeneous analogues and was repeatedly and conveniently recycled, features that were attributed to its ability to form homogeneous phases.
- Bielawski, Christopher W.,Jung, Hyosic
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p. 15598 - 15603
(2020/05/05)
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- High-Throughput Mass Spectrometry Screening Platform for Discovering New Chemical Reactions under Uncatalyzed, Solvent-Free Experimental Conditions
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A gas-phase high-throughput reaction screening platform was developed for the first time to study chemical structures of closely related functional groups and for the discovery of novel organic reaction pathways. Experiments were performed using the contained atmospheric pressure chemical ionization (APCI) source that enabled nonthermal, nonequilibrium plasma chemistry to be monitored by mass spectrometry (MS) in real time. This contained-APCI MS platform allowed an array of reagents to be tested, resulting in the studies of multiple gas-phase reactions in parallel. By exposing headspace vapor of the selected reagents to corona discharge, solvent-free Borsche-Drecsel cyclization reaction, Katritzky chemistry, and Paal-Knorr pyrrole synthesis were examined in the gas phase, outside the high vacuum environment of the mass spectrometer. A new radical-mediated hydrazine coupling reaction was also discovered, which provided a selective pathway to synthesize secondary amines without using a catalyst. The mechanisms of these atmospheric pressure gas-phase reactions were explored through the direct capture of intermediates and via comparison with the corresponding bulk solution and droplet-phase reactions.
- Kulyk, Dmytro S.,Amoah, Enoch,Badu-Tawiah, Abraham K.
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p. 15025 - 15033
(2020/12/01)
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- Iron-catalyzed reductive coupling of nitroarenes with olefins: Intermediate of iron-nitroso complex
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Using a single half-sandwich iron(II) compound, CpFe(1,2-Ph2PC6H4S)(NCMe) (Cp- = C5Me5-, 1) as a catalyst, reductive coupling of nitroarenes with olefins has been achieved by a well-defined iron(II)/(EtO)3SiH system. Through either inter- or intramolecular reductive coupling, various branched amines and indole derivatives have been directly synthesized in one-pot. Mechanistic studies showed that the catalysis is initiated by activation of nitroarenes by the iron(II) catalyst with silane, generating iron-nitrosoarene intermediate for the C-N bond coupling.
- Song, Heng,Yang, Zhuoyi,Tung, Chen-Ho,Wang, Wenguang
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p. 276 - 281
(2019/12/24)
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- Aerobic Dehydrogenation of N-Heterocycles with Grubbs Catalyst: Its Application to Assisted-Tandem Catalysis to Construct N-Containing Fused Heteroarenes
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An aerobic dehydrogenation of nitrogen-containing heterocycles catalyzed by Grubbs catalyst is developed. The reaction is applicable to various nitrogen-containing heterocycles. The exceptionally high functional group compatibility of this method was confirmed by the oxidation of an unprotected dihydroindolactam V to indolactam V. Furthermore, by taking advantage of the oxygen-mediated structural change of the Grubbs catalyst, we integrated ring-closing metathesis and subsequent aerobic dehydrogenation to develop the novel assisted-tandem catalysis using molecular oxygen as a chemical trigger. The utility of the assisted-tandem catalysis was demonstrated by the concise synthesis of N-containing fused heteroarenes including a natural antibiotic, pyocyanine.
- Kawauchi, Daichi,Noda, Kenta,Komatsu, Yoshiyuki,Yoshida, Kei,Ueda, Hirofumi,Tokuyama, Hidetoshi
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supporting information
p. 15793 - 15798
(2020/10/12)
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- Application and preparation method of gamma-carbolin-hydroxamic acid anti-tumor metastasis compound
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The invention belongs to the field of biological medicines, and particularly relates to application and a preparation method of a gamma-carbolin-hydroxamic acid anti-tumor metastasis compound. It hasbeen proved that HDACi (histone deacetylase inhibitor) plays a role in the tumor development process through multiple mechanisms, such as promoting tumor cell invasion and migration, promoting tumor tissue angiogenesis, enhancing drug resistance of tumor cells to drugs and inhibiting tumor cell differentiation and apoptosis. The gamma-carboline derivative has various pharmacological characteristics, such as anti-tumor, anti-inflammatory and antibacterial activity. Meanwhile, the molecular weight of the gamma-carboline is small, and the bioavailability is high. According to the invention, a gamma-carboline structure is used as a CAP region and is combined with a hydroxamic acid structure to synthesize a novel anti-tumor metastasis histone deacetylase inhibitor. The synthesized compound is subjected to biological experiment detection, including a cell proliferation experiment, an anti-migration experiment and a cell apoptosis experiment.
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Paragraph 0014; 0026
(2020/11/01)
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- Supported dual-acidic 1,3-disulfoimidazolium chlorozincate@HZSM-5 as a promising heterogeneous catalyst for synthesis of indole derivatives
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HZSM-5-supported Br?nsted and Lewis acidic ionic solid 1,3-disulfoimidazolium chlorozincate materials ([dsim]2[ZnCl4]@HZSM-5) were synthesized with various ratios (3, 6, 9, 17 and 50% w/w). The heterogeneous materials were characterized via a variety of spectroscopic techniques. Dual acidity of these materials was determined using specified techniques. These acidic solids were examined as stable heterogeneous catalysts for the Fischer indole reaction of equimolar amounts of phenylhydrazine hydrochloride and various aliphatic or aromatic ketones at 80–90°C in neat condition to produce substituted indole derivatives. The efficient 17% ionic salt-loaded HZSM-5 composite was easily reused for ten consecutive cycles with a slight loss of its activity. The recycled catalyst was further analysed using powder X-ray diffraction and inductively coupled plasma optical emission spectrometric techniques.
- Saikia, Susmita,Puri, Krishna,Borah, Ruli
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- PYRIDINE BASED IONIC FLUORIDE FOR CATALYZING INDOLE AND TETRAZOLE FORMATION
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A pyridine based ionic liquid with a fluoride counter anion which catalyzes Fischer indole reaction and click chemistry. Methods of preparing the ionic liquid, and methods of utilizing the ionic liquid as a catalyst to synthesize indoles/indolenines and tetrazoles are also provided.
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Paragraph 0031; 0115; 0116
(2020/01/02)
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- Visible-light-induced oxidation/[3 + 2] cycloaddition/oxidative aromatization to construct benzo[ a]carbazoles from 1,2,3,4-tetrahydronaphthalene and arylhydrazine hydrochlorides
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An efficient synthesis of benzo[a]carbazoles via visible-light-induced tandem oxidation/[3 + 2] cycloaddition/oxidative aromatization reactions was reported. The benzylic C(sp3)-H of tetrahydronaphthalene was activated through visible-light photoredox catalyst with oxygen as the clean oxidant under mild reaction conditions. This protocol proceeds efficiently with broad substrate scope, and the mechanism study was performed.
- Shen, Jiaxuan,Li, Nannan,Yu, Yanjiang,Ma, Chunhua
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p. 7179 - 7183
(2019/09/30)
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- Synthesis and evaluation of indole derivatives as photosynthesis and plant growth inhibitors
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Indole derivatives were synthetized based on the Fischer indole methodology using different phenyl hydrazine hydrochlorides and either cyclohexanone or 2-butanone. The pre- and post-emergent herbicidal activities were evaluated against Ipomoea grandifolia. A carbazole, 6-chloro-2,3,4,9-tetrahydro-1H-carbazole (3b), decreased the PIabs parameter by 32% and increased the cross-section related parameters, indicating the inactivation of the reaction center on photosystem II. Compound 3b acts as a post-emergent herbicide prototype since dry biomass was reduced by 50%, corroborating the fluorescence results. Comparing instead with a germination experiment, 2,3,4,9-tetrahydro-1H-carbazole (3a) was found to be the most effective agent, inhibiting seed germination by 22% and decreasing root length by 50%. The tetrahydrocarbazoles showed better results than indole derivatives potentially due to the presence of methylene groups at structures, which increase the compounds' lipophilicity and may facilitate their access to the plant. In addition, electron withdrawing groups on the aromatic ring were found to correlate with increased herbicide activity. Further optimization of this series towards the development of herbicides is ongoing.
- Mendes, Mylla Cristie Da Silva,Fazolo, Bruno Rodrigues,De Souza, Jéssica Maria,De Vasconcelos, Leonardo Gomes,De Sousa Junior, Paulo Teixeira,Dall'Oglio, Evandro Luiz,Soares, Marcos Ant?nio,Sampaio, Olívia Moreira,Vieira, Lucas Campos Curcino
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p. 1350 - 1358
(2019/06/19)
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- Cu-Catalyzed Oxidation of C2 and C3 Alkyl-Substituted Indole via Acyl Nitroso Reagents
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The selective oxidation of C2-alkyl-substituted indoles to 3-oxindole and the selective C-H oxygenation or amination of C2,C3-dialkyl-substituted indoles at C2 are reported under mild conditions. The position of the alkyl substitution on the indole directs the reaction to different pathways under similar conditions.
- Zhang, Jun,Torabi Kohlbouni, Saeedeh,Borhan, Babak
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supporting information
p. 14 - 17
(2019/01/08)
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- Copper(II) catalyzed aromatization of tetrahydrocarbazole: An unprecedented protocol and its utility towards the synthesis of carbazole alkaloids
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An efficient protocol for the aromatization of tetrahydrocarbazole is described by using catalytic copper(II) chloride dihydrate in DMSO. This newly established methodology has utilized towards the synthesis of naturally occurring carbazole alkaloids, namely 3-methylcarbazole, 3-formyl carbazole, glycozoline, glycozolicine and clauszoline-K. In addition, the protocol is generalized for the aromatization of N-substituted tetrahydrocarbazole, 1,2,3,4-tetrahydroquinoline, 1,2,3,4-tetrahydroisoquinoline and 1,2,3,4-tetrahydro β-carboline to give the corresponding heteroaromatic compounds from very good to excellent yield. Moreover, this method has been proven to be tolerant to a broad range of functional groups with excellent yields.
- Dalvi, Bhakti A.,Lokhande, Pradeep D.
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supporting information
p. 2145 - 2149
(2018/05/08)
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- Design, synthesis and pharmacological evaluation of some novel tetrahydrocarbazoles as potential COX-2 inhibitors
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Background: NSAIDs have been extensively used for the treatment of pain and inflammation. There are about 30 different NSAIDs available in market and about 80 percent of prescriptions throughout the world contains one or the other painkiller. Chronic use of these drugs has many side effects such as gastric ulceration and the COX-2 inhibitors suffer from major drawback of cardiac toxicity. The need for a potential and safe NSAIDs has always led to the development of newer, better and safer drug molecules. In this article design and development of tetrahydrocarbazole derivatives with very low ulcerative index is reported. Methods: Fifteen tetrahydrocarbazole derivatives were synthesized on the basis of structural homology to indomethacin. Compounds were synthesized and characterized on the basis of spectral data. These were studied for their analgesic, anti-inflammatory and ulcerogenic activities. These compounds were subjected to molecular docking studies for understanding the possible mechanism of action and target. Results: The designed compounds were synthesized successfully in good yield and purity without much efforts. All compounds were evaluated by in vitro and in vivo assay, molecular modelling studies and ulcerative index. One of the compound (3-Aminophenyl) (6-chloro-1,2,3,4-tetrahydro-9H-carbazol-9-yl) methanone 13 was found to be highly active in the in vitro and in vivo assessment also it was found to be highly safe on ulcerogenic index compared to the standard drugs. Conclusion: Tetrahydrocarbazoles were found to be promising scaffolds which can be developed into safe and potential non-steroidal anti-inflammatory agents.
- Sakinala, Padmavathi,Chikhale, Rupesh,Tajne, Madhukar
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p. 437 - 449
(2018/04/20)
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- Br?nsted-Acid-Promoted Rh-Catalyzed Asymmetric Hydrogenation of N-Unprotected Indoles: A Cocatalysis of Transition Metal and Anion Binding
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The incorporation of Br?nsted acid, thiourea anion binding, and transition metal catalysis enables an efficient method to synthesize chiral indolines via hydrogenation of indoles. Catalyzed by a rhodium/ZhaoPhos complex, asymmetric hydrogenation of unprotected indoles is performed smoothly with excellent enantioselectivities (up to 99% ee, up to 400 TON). Br?nsted acid HCl activates indoles to form iminium ion intermediates. Mechanistic studies support the assumption that anion binding plays a crucial role as a secondary interaction. DFT calculations reveal an outer-sphere mechanism in this chemical transformation.
- Wen, Jialin,Fan, Xiangru,Tan, Renchang,Chien, Hui-Chun,Zhou, Qinghai,Chung, Lung Wa,Zhang, Xumu
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supporting information
p. 2143 - 2147
(2018/04/30)
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- Biphilic Organophosphorus-Catalyzed Intramolecular Csp2-H Amination: Evidence for a Nitrenoid in Catalytic Cadogan Cyclizations
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A small-ring phosphacycloalkane (1,2,2,3,4,4-hexamethylphosphetane, 3) catalyzes intramolecular C-N bond forming heterocyclization of o-nitrobiaryl and -styrenyl derivatives in the presence of a hydrosilane terminal reductant. The method provides scalable access to diverse carbazole and indole compounds under operationally trivial homogeneous organocatalytic conditions, as demonstrated by 17 examples conducted on 1 g scale. In situ NMR reaction monitoring studies support a mechanism involving catalytic PIII/PV=O cycling, where tricoordinate phosphorus compound 3 represents the catalytic resting state. For the catalytic conversion of o-nitrobiphenyl to carbazole, the kinetic reaction order was determined for phosphetane catalyst 3 (first order), substrate (first order), and phenylsilane (zeroth order). For differentially 5-substituted 2-nitrobiphenyls, the transformation is accelerated by electron-withdrawing substituents (Hammett factor ? = +1.5), consistent with the accrual of negative charge on the nitro substrate in the rate-determining step. DFT modeling of the turnover-limiting deoxygenation event implicates a rate-determining (3 + 1) cheletropic addition between the phosphetane catalyst 3 and 2-nitrobiphenyl substrate to form an unobserved pentacoordinate spiro-bicyclic dioxazaphosphetane, which decomposes via (2 + 2) cycloreversion giving 1 equiv of phosphetane P-oxide 3·[O] and 2-nitrosobiphenyl. Experimental and computational investigations into the C-N bond forming event suggest the involvement of an oxazaphosphirane (2 + 1) adduct between 3 and 2-nitrosobiphenyl, which evolves through loss of phosphetane P-oxide 3·[O] to give the observed carbazole product via C-H insertion in a nitrene-like fashion.
- Nykaza, Trevor V.,Ramirez, Antonio,Harrison, Tyler S.,Luzung, Michael R.,Radosevich, Alexander T.
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supporting information
p. 3103 - 3113
(2018/03/08)
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- A Palladium-Catalyzed Ullmann Cross-Coupling/Reductive Cyclization Route to the Carbazole Natural Products 3-Methyl-9H-carbazole, Glycoborine, Glycozoline, Clauszoline K, Mukonine, and Karapinchamine A
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The title natural products 2-7 have been prepared by reductive cyclization of the relevant 2-arylcyclohex-2-en-1-one (e.g. 20) to the corresponding tetrahydrocarbazole and dehydrogenation (aromatization) of this to give the target carbazole (e.g. 4). Compounds such as 20 were prepared using a palladium-catalyzed Ullmann cross-coupling reaction between the appropriate 2-iodocyclohex-2-en-1-one and o-halonitrobenzene.
- Yan, Qiao,Gin, Emma,Wasinska-Kalwa, Malgorzata,Banwell, Martin G.,Carr, Paul D.
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p. 4148 - 4159
(2017/04/27)
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- Production method of carbazole
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The invention relates to a production method of carbazole, which includes two steps: 1) with phenylhydrazine hydrochloride as raw material, performing a reaction with cyclohexanone in acetic acid to produce tetrahydrocarbazole; 2) mixing the tetrahydrocarbazole with a catalyst and adding an organic solvent, and performing a catalytic dehydrogenation reaction at 140-300 DEG C to obtain the carbazole. The method employs economical and easy-to-obtained raw materials and catalyst, has simple processes and high carbazole yield, is low in cost, has mild reaction conditions and has convenience in industrial production.
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Paragraph 0015; 0021-0024; 0030; 0036; 0042; 0048; 0060
(2017/10/06)
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- Compound having general formula and application to organic electroluminescence
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The invention discloses a compound applied to organic electroluminescent devices and application. The compound is shown by the general formula in the description, wherein R and R are the same or different, and each of R and R is independently selected from hydrogen, halogen, substituted or unsubstituted C1 to C10 alkyl, and substituted or unsubstituted C6 to C30 aryl; Ar to Ar are the same or different, and each of the Ar to Ar is independently selected from hydrogen, halogen, C1 to C10 alkyl, substituted or unsubstituted C6 to C30 aryl, and substituted or unsubstituted C2 to C30 heteroaryl. According to the invention, an organic amine unit is replaced with a carbazole structural unit, the oxidation resistance of the material is improved and the defects of the material such as easy discoloration can be overcome. A generated cyclic polyamide structure has extremely high thermodynamics and chemical stability and can meet the requirements that the material does not decompose in a vapor deposition process, thereby affecting the performance of the devices; an adopted 1,2,4,5-tetracarboxylic acid structure can ensure sufficient electron affinity, so as to enable the material to have strong electron injection performance; the compound has a good intermolecular interaction effect, and can ensure that the material has higher electron transport performance.
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Paragraph 0045; 0046
(2017/11/18)
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- Synthesis of tricyclic units of indole alkaloids: Application of Fischer indolization and olefin metathesis
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Simple synthetic approaches to pyridocarbazole and azepinocarbazole derivatives have been reported via Fischer indolization, Grignard reaction and olefin metathesis as key steps. In addition, a combination Sonogashira coupling and Pauson-Khand reaction has been used to assemble extended pyridocarbazole derivative.
- Kotha, Sambasivarao,Aswar, Vikas R.,Singhal, Gaurav
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p. 6436 - 6442
(2017/10/09)
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- N, N -Dimethylpyridin-4-amine (DMAP) based ionic liquids: Evaluation of physical properties via molecular dynamics simulations and application as a catalyst for Fisher indole and 1 H -tetrazole synthesis
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The last few decades have seen a rapid increase in the use of ionic liquids (ILs) as a green alternative to traditional solvents in organic synthesis. The use of ILs as catalysts has also increased in recent years. Herein we the report synthesis of new N,N-dimethylpyridin-4-amine (DMAP) based ionic liquids (ILs) as new and efficient catalysts for the facile synthesis of indoles (via Fischer indole synthesis), and 1H-tetrazoles (via click chemistry). The method is environmentally friendly, requiring only minimum catalyst loading (0.2 equiv. for Fischer indole synthesis). In the case of 1H-tetrazole formation (via click chemistry), the reaction was carried out under a solvent free environment. Moreover, thermal studies (TGA, DTG and DSC) of DMAP-ILs (2, 3) have also been carried out to elicit their stability for temperature dependent reactions. Application of molecular dynamics simulations provided valuable insights into the structural and transport properties of these ionic liquids. An MP2 method was applied to evaluate the stability of the compound via binding energy calculations.
- Ghumro, Sarfaraz Ali,Saleem, Sana,Al-Rashida, Mariya,Iqbal, Nafees,Alharthy, Rima D.,Ahmed, Shakil,Moin, Syed Tarique,Hameed, Abdul
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p. 34197 - 34207
(2017/07/17)
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- Selective hydrogenation of N-heterocyclic compounds using Ru nanocatalysts in ionic liquids
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N-Heterocyclic compounds have been tested in the selective hydrogenation catalysed by small 1-3 nm sized Ru nanoparticles (NPs) embedded in various imidazolium based ionic liquids (ILs). Particularly a diol-functionalised IL shows the best performance in the hydrogenation of quinoline to 1,2,3,4-tetrahydroquinoline (1THQ) with up to 99% selectivity.
- Konnerth, Hannelore,Prechtl, Martin H. G.
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supporting information
p. 2762 - 2767
(2017/07/24)
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- Catalytic α-Arylation of Imines Leading to N-Unprotected Indoles and Azaindoles
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A palladium N-heterocyclic carbene catalyzed methodology for the synthesis of substituted, N-unprotected indoles and azaindoles is reported. The protocol permits access to various, highly substituted members of these classes of compounds. Although two possible reaction pathways (deprotonative and Heck-like) can be proposed, control experiments, supported by computational studies, point toward a deprotonative mechanism being operative.
- Marelli, Enrico,Corpet, Martin,Minenkov, Yury,Neyyappadath, Rifahath M.,Bismuto, Alessandro,Buccolini, Giulia,Curcio, Massimiliano,Cavallo, Luigi,Nolan, Steven P.
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p. 2930 - 2938
(2016/07/06)
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- Catalytic synthesis method of indole compounds
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The invention discloses a catalytic synthesis method of indole compounds.The method includes the following steps of firstly, conducting stirring reaction on ortho-nitrostyrolene or derivatives of ortho-nitrostyrolene, bis(pinacolato)diboron, alkali and low-grade saturated monohydric alcohol under the atmosphere of nitrogen; secondly, cooling the reaction product in the first step to the room temperature, adding ethyl acetate to be sufficiently mixed, and washing with ethyl acetate after filtering; thirdly, spin-drying low-grade saturated monohydric alcohol in an organic phase of the material obtained in the second step, passing through a silica gel column, and drip washing the silica gel column with eluent composed of petroleum ether and ethyl acetate to obtain pure products, namely, the indole compounds.By means of the method, under the neutral conditions, bis(pinacolato)diboron low in price serves as the raw material, friendly low-grade saturated monohydric alcohol serves as the solvent, the indole compounds are obtained through simple operation, the raw materials are low in price and easy to obtain, efficiency and safety are high, and wide expandability and good industrial application prospects are achieved.
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Paragraph 0032; 0033; 0034; 0035
(2016/10/10)
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- Method for preparing indole compounds through catalysis of ionic liquid
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The invention relates to a green synthesis method of one type of indole derivatives. The method is characterized by taking sulfonic acid ionic liquid as a catalyst, taking aliphatic ketone, aromatic ketone and aromatic hydrazine hydrochloride as raw materials, reacting in water, filtering and drying a reaction mixture to obtain indole compounds. The method is simple to operate; the raw materials are low intoxicity and low in costs; the reaction condition is mild; the product is easy to separate; the synthesis process is environmentally-friendly; the indole compounds are high in purity; the catalyst can be directly reused without treatment; the method is green and environmentally-friendly, and is suitable for industrial production.
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Paragraph 0040-0042
(2018/02/04)
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- Novel and Efficient Heterogeneous 4-Methylbenzenesulfonic Acid-Based Ionic Liquid Supported on Silica Gel for Greener Fischer Indole Synthesis
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In this work, a functionalizing active species 4-methylbenzenesulfonic acid-based IL on silica gel (IL-SO3H-SiO2) has been prepared, and characterized by FT-IR, XRD, TGA, SEM and EDX spectra. Then, IL-SO3H-SiO2 was utilized as an efficient and heterogeneous catalyst for the synthesis of indoles via the one-pot Fischer reaction of phenyl hydrazines with ketones or aldehydes at room temperature. The heterogeneous catalyst could be recovered easily by filtration and reused many times without significant loss of its catalytic activity.
- Hu, Yu-Lin,Fang, Dong,Li, Dong-Sheng
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p. 968 - 976
(2016/04/20)
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- A diversity-oriented approach to indolocarbazoles: Via Fischer indolization and olefin metathesis: Total synthesis of tjipanazole D and i
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New synthetic strategies to indolocarbazoles have been reported via two-fold Fischer indolization under green conditions using l-(+)-tartaric acid and N,N-dimethyl urea. Starting with cyclohexanone, a bench-top starting material, this methodology has been extended to the total synthesis of natural products such as tjipanazoles D and I as well as the core structure of asteropusazole and racemosin B. Here, atom economical reactions like ring-closing metathesis, enyne-metathesis, and the Diels-Alder reaction have been used as key steps. Diverse strategies demonstrated here are useful in medicinal chemistry and materials science to design a library of decorated indoles.
- Kotha, Sambasivarao,Saifuddin, Mohammad,Aswar, Vikas R.
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p. 9868 - 9873
(2016/10/31)
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- Indoline derivatives a series of structure containing asymmetric squaraine cyanine small molecule and its application
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The invention provides a series of novel asymmetric squarine micromolecules, and an application thereof. By introducing different electricity-rich aromatic units in two ends of a squaric acid four-membered ring as donor units, a series of low narrow-gap asymmetric squarine micromolecule photovoltaic materials are designed and synthesized. The series of the low narrow-gap asymmetric squarine micromolecule photovoltaic materials have strong absorption in visible and near-infrared light regions; absorption spectra cover400-900 nm; and HOMO and LUMO of the series of the low narrow-gap asymmetric squarine micromolecule photovoltaic materials can match well with energy levels of an acceptor material PCBM to obtain a high open-circuit voltage. The compounds have good solubility and film-forming property, so that the compounds can be applied in bulk hetero-junction organic solar cells processed by low-cost solution. Performances of the organic solar cells with asymmetric squaric acid macromolecules as donor materials can reach an open-circuit voltage Voc=0.72-1.05 V, a short-circuit current Jsc=8.80-12.67 mA/cm, a fill factor (FF)=0.38-0.55, and photoelectric conversion efficiency (PCE)=2.41-6.10%.
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Paragraph 0055-0058
(2019/02/02)
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- Dearomatization of Indoles via Palladium-Catalyzed Allylic C-H Activation
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The first Pd-catalyzed allylic dearomatization of substituted indoles triggered by C-H bond activation is reported. The presence of a catalytic amount of 2,5-DMBQ is proven to be a key factor for the high yield. This one-pot tandem allylic C-H activation/dearomatization sequence provides a straightforward access to 3,3-disubstituted indolines.
- Zhang, Heng,Hu, Rong-Bin,Liu, Na,Li, Shi-Xia,Yang, Shang-Dong
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supporting information
p. 28 - 31
(2016/01/15)
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- A general synthesis of arylindoles and (1-arylvinyl)carbazoles: Via a one-pot reaction from N -tosylhydrazones and 2-nitro-haloarenes and their potential application to colon cancer
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A convergent and effective synthesis of 3-aryl-indoles, 2,3-diaryl indoles, and (1-arylvinyl)carbazoles from a one-pot sequence involving the coupling of N-tosylhydrazones with ortho-nitro-haloarenes followed by a cyclization has been developed. Compound 5i exhibits excellent antiproliferative activity in the low nM range against colon cancer cell lines.
- Bzeih, Tourin,Naret, Timothée,Hachem, Ali,Jaber, Nada,Khalaf, Ali,Bignon, Jerome,Brion, Jean-Daniel,Alami, Mouad,Hamze, Abdallah
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p. 13027 - 13030
(2016/11/09)
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- Iron-Catalyzed Intramolecular C(sp2)-H Amination
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The nucleophilic iron complex Bu4N[Fe(CO)3(NO)] (TBA[Fe]) catalyzes the direct intramolecular C-H amination of α-azidobiaryls and (azidoaryl)alkenes into the corresponding carbazoles and indoles, respectively, under mild conditions and with low catalyst loadings. These features and the broad functional-group tolerance render this method a particularly attractive alternative to established noble-metal-based procedures.
- Alt, Isabel T.,Plietker, Bernd
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p. 1519 - 1522
(2016/02/14)
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