- New synthesis of isoquinoline derivatives by reactions of 2-(2-methoxyethenyl)benzonitriles with organolithiums and lithium dialkylamides
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A simple and efficient synthesis of 1-alkyl(or aryl)isoquinoline and isoquinolin-1-amine derivatives based on intramolecular cyclization of 2-(2-methoxyethenyl)benzonitriles initiated by the addition of alkyl(or aryl)lithiums and lithium dialkylamides to the nitrile carbons, respectively, is described.
- Kobayashi, Kazuhiro,Shiokawa, Taiyo,Morikawa, Osamu,Konishi, Hisatoshi
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- High-efficiency electrophosphorescent fluorene-alt-carbazole copolymers N-grafted with cyclometalated Ir complexes
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A series of electrophosphorescent conjugated fluorene-alt-carbazole copolymers are synthesized by Suzuki polycondensation. A diketone-ended alkyl chain which is grafted in the N-position of carbazole serves as a ligand to form a pendant cyclometalated Ir complex with 1-phenylisoquinoline (Piq), 2-naphthylpyridine (Napy), and 2-phenylquinoline (Phq). The PL efficiencies of PFCzIrPiq and PFCzIrPhq copolymers are around 60% and 70%, respectively. EL emission from the backbone of PFCzIrPiq and PFCzIrPhq copolymers is completely quenched even though the Ir complex contents in the polymers are as low as 0.5 mol %. The device of PFCzIrPiq05 copolymer shows the highest external quantum efficiency of 4.9% ph/el and the luminous efficiency of 4.0 cd/A with 240 cd/m2 at a bias voltage of 7.7 V and a peak emission of 610 nm. The device efficiency of PFCzIrPiq05 copolymer still remains high (QE ext = 3.4% ph/el and LE = 2.9 cd/A) with a luminance of 2978 cd/m2 even at a current density of 100 mA/cm2. The enhancement of the device performance could be due to the higher triplet energy and meanwhile to suitable HOMO and LUMO levels for efficient charge injection by introducing a carbazole unit into the polyfluorene backbone at the 3,6-linkage and blending PBD into the copolymers.
- Jiang, Jiaxing,Jiang, Changyun,Yang, Wei,Zhen, Hongyu,Huang, Fei,Cao, Yong
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- A series of red-light-emitting ionic iridium complexes: Structures, excited state properties, and application in electroluminescent devices
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A series of ionic diiminoiridium complexes [Ir(piq-C∧N) 2(L-N∧N)](PF6) were prepared, where piq-C∧N is 1-phenylisoquinolinato and L-N∧N are bidentate N-coordinating ligands: 2,2′-bipyridine (bpy), 4,4′-dimethyl-2,2′-bipyridine (mbpym), 5,5′-bis(thiopen-2-yl)-2,2′-bipyridine (tbpyt), and 5,5′-bis(9,9-dioctylfluoren-2-yl)-2,2′-bipyridine (FbpyF). X-ray diffraction studies of [Ir(piq)2(mbpym)](PF6) revealed that the iridium center adopts a distorted octahedral geometry. All complexes exhibited intense and long-lived emission at room temperature. The substituents on the 2,2′-bipyridine moieties influence the photophysical and electrochemical properties. The excited states were investigated through theoretical calculations together with photophysical and electrochemical properties. It was found that the excited state of the [Ir(piq) 2(FbpyF)](PF6) complex can be assigned to a mixed character of 3LC (πN∧N→π *N∧N), 3MLCT, 3LLCT (π C∧N→π*N∧N), and 3LC (πC∧N→π*C∧N). In addition, the alkylfluorene-substituted complex, [Ir(piq)2(FbpyF)](PF6), had relatively high quantum efficiency and good film-forming ability, and it was expected to be a good candidate for lighting and display applications. A nondoped, single-layer device that incorporates this complex as a light-emitting layer was fabricated and red phosphorescence was obtained. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
- Liu, Shu-Juan,Zhao, Qiang,Fan, Qu-Li,Huang, Wei
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- Efficient and stable deep-red phosphorescent organic light-emitting diodes based on an iridium complex containing a benzoxazole-substituted ancillary ligand
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In the deep red: A biscyclometalated deep-red phosphorescent dopant containing a new ancillary ligand, iridium(III) bis(1-phenylisoquinolinato-N, C2′) (2-(benzo[d]oxazol-2-yl)phenol) (Ir(piq)2bop) has been designed and synthesized. B
- Wu, Chuan,Tao, Silu,Chen, Mingming,Wong, Fu-Lung,Yuan, Yi,Mo, Hin-Wai,Zhao, Weiming,Lee, Chun-Sing
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- Novel cyclometalated Ru(II) complexes containing isoquinoline ligands: Synthesis, characterization, cellular uptake and in vitro cytotoxicity
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Two novel cyclometalated Ru(II) complexes containing isoquinoline ligand, [Ru(bpy)2(1-Ph-IQ)](PF6), (bpy = 2,2′-bipyridine; 1-Ph-IQ = 1-phenylisoquinoline; RuIQ-1) and [Ru(phen)2(1-Ph-IQ)](PF6) (phen = 1,10-phenanthroline; RuIQ-2) were found to show high cytotoxic activity against NCI–H460, A549, HeLa and MCF-7 cell lines. Notably, both of them exhibited IC50 values that were an order of magnitude lower than those of clinical cisplatin and two structurally similar Ru(II)-isoquinoline complexes [Ru(bpy)2(1-Py-IQ)](PF6)2 (Ru3) and [Ru(phen)2(1-Py-IQ)](PF6)2 (Ru4) (1-Py-IQ = 1-pyridine-2-yl). The cellular uptake and intracellular localization displayed that the two cyclometalated Ru(II) complexes entered NCI–H460 cancer cells dominantly via endocytosis pathway, and preferentially distributed in the nucleus. Further investigations on the apoptosis-inducing mechanisms of RuIQ-1 and RuIQ-2 revealed that the two complexes could cause S, G2/M double-cycle arrest by regulating cell cycle related proteins. The two complexes also could reduce the mitochondrial membrane potential (MMP), promote the generation of intracellular ROS and trigger DNA damage, and then lead to apoptosis-mediated cell death. More importantly, RuIQ-2 exhibits low toxicity both towards normal HBE cells in vitro and zebrafish embryos in vivo. Accordingly, the developed complexes hold great potential to be developed as novel therapeutics for effective and low-toxic cancer treatment.
- Chen, Jincan,Wang, Jie,Deng, Yuanyuan,Li, Baojun,Li, Chengpeng,Lin, Yuxue,Yang, Dongbin,Zhang, Huanyun,Chen, Lanmei,Wang, Tao
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- Geometric and electronic effects on the performance of a bifunctional Ru2P catalyst in the hydrogenation and acceptorless dehydrogenation of N-heteroarenes
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The development of bifunctional catalysts for the efficient hydrogenation and acceptorless dehydrogenation of N-heterocycles is a challenge. In this study, Ru2P/AC effectively promoted reversible transformations between unsaturated and saturated N-heterocycles affording yields of 98% and 99%, respectively. Moreover, a remarkable enhancement in the reusability of Ru2P/AC was observed compared with other Ru-based catalysts. According to density functional theory calculations, the superior performance of Ru2P/AC was ascribed to specific synergistic factors, namely geometric and electronic effects induced by P. P greatly reduced the large Ru-Ru ensembles and finely modified the electronic structures, leading to a low reaction barrier and high desorption ability of the catalyst, further boosting the hydrogenation and acceptorless dehydrogenation processes.
- Shao, Fangjun,Yao, Zihao,Gao, Yijing,Zhou, Qiang,Bao, Zhikang,Zhuang, Guilin,Zhong, Xing,Wu, Chuan,Wei, Zhongzhe,Wang, Jianguo
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p. 1185 - 1194
(2021/02/16)
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- Efficient acceptorless dehydrogenation of hydrogen-rich N-heterocycles photocatalyzed by Ni(OH)2@CdSe/CdS quantum dots
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Hydrogen storage using liquid organic hydrogen carriers (LOHCs) is a promising hydrogen storage technology; however, the hydrogen release process typically requires a high temperature. Developing dehydrogenation technology under mild conditions is highly desirable. Herein, a new approach for photocatalytic acceptorless dehydrogenation of hydrogen-rich LOHCs using Ni(OH)2@CdSe/CdS QDs as the photocatalyst was demonstrated. 1,2,3,4-Tetrahydroquinoline (THQ), iso-THQ, indoline, and their derivatives were selected as hydrogen-rich substrates, which exhibit excellent dehydrogenation efficiency with the release of hydrogen photocatalyzed by Ni(OH)2@CdSe/CdS QDs. Up to 100% yields of hydrogen and over 90% yields of complete dehydrogenation products were obtained at ambient temperature. Isotope tracer studies indicate a stepwise pathway, beginning with the photocatalytic oxidation of the substrate to release a proton and followed by proton exchange with heavy water. This work provides a promising alternative strategy to develop highly efficient, low cost and earth-abundant photocatalysts for acceptorless dehydrogenation of hydrogen-rich LOHCs.
- Liu, Yanpeng,Yu, Tianjun,Zeng, Yi,Chen, Jinping,Yang, Guoqiang,Li, Yi
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p. 3810 - 3817
(2021/06/18)
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- Transition metal complex, mixture, composition and organic electronic device
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The invention discloses a transition metal complex containing gold (Au). The transition metal complex is shown as a general formula (1). According to the metal complex disclosed by the invention, due to a relatively stable six-membered ring aniline structure, the metal complex can be used as a doping material of a light-emitting layer in an organic electronic light-emitting device, so the stability of the device is improved, and meanwhile, the starting voltage is reduced to prolong the service life of the device.
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Paragraph 0312; 0325; 0326
(2021/06/12)
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- Transition metal complex, polymer, mixture, composition and organic electronic device
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The invention discloses a transition metal complex, a polymer, a mixture, a composition and an organic electronic device. According to the transition metal complex, due to the fact that the metal organic complex contains a ketone group and has excellent electron transmission capacity, the compound contains an arylamine group and also has excellent hole transmission capacity, and the transition metal complex has a stable six-membered ring structure, when the transition metal complex serves as a light-emitting layer doping material and is applied to an organic electronic device, especially an OLED, the light-emitting efficiency of the device can be improved, and the service life of the device can be prolonged.
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Paragraph 0273-0276
(2021/06/23)
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- Transition metal complex, polymer, mixture, composition and organic electronic device
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The invention discloses a transition metal complex, a polymer, a mixture, a composition and an organic electronic device. According to the transition metal complex provided by the invention, because the transition metal complex contains an ester group and a relatively stable six-membered ring structure, the complex has excellent electron transmission capability, and can improve the luminous efficiency and prolong the service life of the device when being used as a luminescent layer doping material in an organic electronic device, especially an OLED (Organic Light Emitting Diode).
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Paragraph 0237-0240
(2021/06/22)
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- Transition metal complex, polymer, mixture, composition and organic electronic device
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The invention discloses a transition metal complex, a polymer, a mixture, a composition and an organic electronic device. When the transition metal complex provided by the invention is used as a light-emitting layer doping material and is applied to an organic electronic device, especially an OLED, the light-emitting efficiency of the device can be improved, and the service life of the device can be prolonged.
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Paragraph 0273-0274; 0282-0283
(2021/06/26)
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- Inhibition of (dppf)nickel-catalysed Suzuki-Miyaura cross-coupling reactions by α-halo-N-heterocycles
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A nickel/dppf catalyst system was found to successfully achieve the Suzuki-Miyaura cross-coupling reactions of 3- and 4-chloropyridine and of 6-chloroquinoline but not of 2-chloropyridine or of other α-halo-N-heterocycles. Further investigations revealed that chloropyridines undergo rapid oxidative addition to [Ni(COD)(dppf)] but that α-halo-N-heterocycles lead to the formation of stable dimeric nickel species that are catalytically inactive in Suzuki-Miyaura cross-coupling reactions. However, the corresponding Kumada-Tamao-Corriu reactions all proceed readily, which is attributed to more rapid transmetalation of Grignard reagents.
- Burton, Paul M.,Cooper, Alasdair K.,Donohoe, William,Greaves, Megan E.,Kennedy, Alan R.,Nelson, David J.,Ronson, Thomas O.
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p. 14074 - 14082
(2021/11/12)
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- Development of versatile and potent monoquaternary reactivators of acetylcholinesterase
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To date, the only treatments developed for poisoning by organophosphorus compounds, the most toxic chemical weapons of mass destruction, have exhibited limited efficacy and versatility. The available causal antidotes are based on reactivation of the enzyme acetylcholinesterase (AChE), which is rapidly and pseudo-irreversibly inhibited by these agents. In this study, we developed a novel series of monoquaternary reactivators combining permanently charged moieties tethered to position 6- of 3-hydroxypyridine-2-aldoxime reactivating subunit. Highlighted representatives (21, 24, and 27; also coded as K1371, K1374, and K1375, respectively) that contained 1-phenylisoquinolinium, 7-amino-1-phenylisoquinolinium and 4-carbamoylpyridinium moieties?as peripheral anionic site ligands, respectively, showed efficacy superior or comparable to that of the clinically used standards. More importantly, these reactivators exhibited wide-spectrum efficacy and were minutely investigated via determination of their reactivation kinetics in parallel with molecular dynamics simulations to study their mechanisms of reactivation of the tabun-inhibited AChE conjugate. To further confirm the potential applicability of these candidates, a mouse in vivo assay was conducted. While K1375 had the lowest acute toxicity and the most suitable pharmacokinetic profile, the oxime K1374 with delayed elimination half-life was the most effective in ameliorating the signs of tabun toxicity. Moreover, both in vitro and in vivo, the versatility of the agents was substantially superior to that of clinically used standards. Their high efficacy and broad-spectrum capability make K1374 and K1375 promising candidates that should be further investigated for their potential as nerve agents and insecticide antidotes.
- Gorecki, Lukas,Hepnarova, Vendula,Karasova, Jana Zdarova,Hrabinova, Martina,Courageux, Charlotte,Dias, José,Kucera, Tomas,Kobrlova, Tereza,Muckova, Lubica,Prchal, Lukas,Malinak, David,Jun, Daniel,Musilek, Kamil,Worek, Franz,Nachon, Florian,Soukup, Ondrej,Korabecny, Jan
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p. 985 - 1001
(2021/02/03)
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- 2-Phosphinoimidazole Ligands: N-H NHC or P-N Coordination Complexes in Palladium-Catalyzed Suzuki-Miyaura Reactions of Aryl Chlorides
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We report the synthesis of two palladium 2-(dialkylphosphino)imidazole complexes and demonstrate their activity as catalysts for Suzuki-Miyaura reactions with (hetero)aryl chlorides at room temperature. Our mechanistic studies demonstrate that these palladium complexes exist as an equilibrium mixture between the P-N coordinated and N-H NHC forms of ligand. Our studies suggest that the N-H NHC form may be important for high catalytic activity in Suzuki-Miyaura reactions with aryl chlorides. These reactions proceed at or near room temperature in good to excellent yields. Heteroaryl chlorides are also reactive at lower catalyst loadings.
- Martinez, Erin E.,Larson, Alexandra J. S.,Fuller, Sydney K.,Petersen, Kathryn M.,Smith, Stacey J.,Michaelis, David J.
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supporting information
p. 1560 - 1564
(2021/05/29)
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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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- DMSO/t-BuONa/O2-Mediated Aerobic Dehydrogenation of Saturated N-Heterocycles
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Aromatic N-heterocycles such as quinolines, isoquinolines, and indolines are synthesized via sodium tert-butoxide-promoted oxidative dehydrogenation of the saturated heterocycles in DMSO solution. This reaction proceeds under mild reaction conditions and has a good functional group tolerance. Mechanistic studies suggest a radical pathway involving hydrogen abstraction of dimsyl radicals from the N-H bond or α-C-H of the substrates and subsequent oxidation of the nitrogen or α-aminoalkyl radicals.
- Cai, Hu,Tan, Wei,Xie, Yongfa,Yang, Ruchun,Yue, Shusheng
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p. 7501 - 7509
(2020/07/07)
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- Preparation method of (S)-1-phenyl-1,2,3,4-tetrahydroisoquinoline
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The invention discloses a preparation method of (S)-1-phenyl-1,2,3,4-tetrahydroisoquinoline. Benzophenone and aminoacetaldehyde dimethyl acetal are used as raw materials, which carry out a reaction under a heating condition to obtain N-(diphenylmethylene)-2,2-dimethoxyethylamine; N-(diphenylmethylene)-2,2-dimethoxyethylamine carries out cyclization under an acid heating condition to obtain 1-phenylisoquinoline, 1-phenylisoquinoline is reduced by using a Pd/C or Ni catalyst to obtain racemic 1-phenyl-1,2,3,4-tetrahydroisoquinoline, and finally 1-phenyl-1,2,3,4-tetrahydroisoquinoline is split byL-mandelic acid to obtain (S)-1-phenyl-1,2,3,4-tetrahydroisoquinoline. Compared with the prior art, benzophenone and aminoacetaldehyde dimethyl acetal are creatively and directly used for reaction,the raw materials are cheap and easy to obtain, and the production cost is greatly reduced. Phosphorus-containing wastewater is not generated, so that the preparation method is safer and more environment-friendly; L-mandelic acid is used for replacing traditional tartaric acid, the crystallization speed is high, the yield is high, the splitting efficiency is improved, and the production period isshortened.
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- Rh/TiO2-Photocatalyzed Acceptorless Dehydrogenation of N-Heterocycles upon Visible-Light Illumination
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TiO2 is an effective and extensively employed photocatalyst, but its practical use in visible-light-mediated organic synthesis is mainly hindered by its wide band gap energy. Herein, we have discovered that Rh-photodeposited TiO2 nanoparticles selectively dehydrogenate N-heterocyclic amines with the concomitant generation of molecular hydrogen gas in an inert atmosphere under visible light (λmax = 453 nm) illumination at room temperature. Initially, a visible-light-sensitive surface complex is formed between the N-heterocycle and TiO2. The acceptorless dehydrogenation of N-heterocycles is initiated by direct electron transfer from the HOMO energy level of the amine via the conduction band of TiO2 to the Rh nanoparticle. The reaction condition was optimized by examining different photodeposited noble metals on the surface of TiO2 and solvents, finding that Rh0 is the most efficient cocatalyst, and 2-propanol is the optimal solvent. Structurally diverse N-heterocycles such as tetrahydroquinolines, tetrahydroisoquinolines, indolines, and others bearing electron-deficient as well as electron-rich substituents underwent the dehydrogenation in good to excellent yields. The amount of released hydrogen gas evinces that only the N-heterocyclic amines are oxidized rather than the dispersant. This developed method demonstrates how UV-active TiO2 can be employed in visible-light-induced synthetic dehydrogenation of amines and simultaneous hydrogen storage applications.
- Bahnemann, Detlef W.,Balayeva, Narmina O.,Dillert, Ralf,Mamiyev, Zamin,Zheng, Nan
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p. 5542 - 5553
(2020/08/25)
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- Meta-dehydrogenative alkylation of arenes with ethers, ketones, and esters catalyzed by ruthenium
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A meta-dehydrogenative alkylation of arenes with cyclic ethers, ketones, and esters catalyzed by ruthenium is achieved in the presence of a di-tert-butyl peroxide (DTBP) oxidant. Interestingly, when quinoline and isoquinoline are employed as the directing group, or a chain ether as alkylation reagent, the system produces Minisci reaction products. Mechanistic study indicates that meta-dehydrogenative alkylation is a radical process initiated by DTBP with the assistance of a CAr-Ru bond ortho/para-directing effect.
- Li, Gang,Gao, Yuan,Jia, Chunqi,Wang, Shichong,Yan, Bingxu,Fang, Yu,Yang, Suling
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supporting information
p. 8758 - 8763
(2020/12/02)
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- Transition-Metal-Free Desulfinative Cross-Coupling of Heteroaryl Sulfinates with Grignard Reagents
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A mild cross-coupling reaction of heteroaryl sulfinates with Grignard reagents has been developed under transition-metal-free conditions. This study provides an example of the SO22- as a leaving group in an aromatic system and an effective methodology for the construction of C-C bond.
- Wei, Jun,Liang, Huamin,Ni, Chuanfa,Sheng, Rong,Hu, Jinbo
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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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- A telescoped Knochel-Hauser/Kumada-Corriu coupling strategy to functionalized aromatic heterocycles
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The direct application of Knochel-Hauser derivative arylmagnesium halides in Kumada-Corriu couplings is described. By utilizing the in situ-generated Grignard reagents, the transmetalation with stoichiometric zinc salts to known Negishi coupling conditions is avoided, thereby streamlining the transformation. Several aromatic hetereocycles participate in the deprotonation and couple with a variety of phenyl iodides and bromides in isolated yields up to 81%. The parent system is demonstrated on 6 g scale with 79% yield, and monitored via ReactIR to show the stability of the Grignard and progression of the deprotonation/C–C coupling reaction.
- Clagg, Kyle,Hold, Sara,Kumar, Archana,Koenig, Stefan G.,Angelaud, Remy
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- Introduction of Heteroaromatic Bases onto Cycloalkanes with BPO
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Heteroaromatic bases, such as lepidine, phenanthridine, isoquinoline, etc., were treated with cycloalkanes, such as cyclopentane, cyclohexane, cycloheptane, cyclooctane, etc., under warming conditions with benzoyl peroxide (BPO) to form heteroaromatic bases bearing cycloalkyl groups in good yields. Here, the inert C(sp3)-H bond of cycloalkanes could be functionalized to C(sp3)-heteroaromatic bases via an oxidative radical reaction pathway under transition-metal-free conditions.
- Zhou, Luan,Togo, Hideo
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p. 1627 - 1634
(2019/02/19)
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- Visible-Light-Mediated Photocatalytic Aerobic Dehydrogenation of N-heterocycles by Surface-Grafted TiO2 and 4-amino-TEMPO
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Herein, the visible-light-induced dehydrogenation of N-heterocycles such as tetrahydroquinolines, tetrahydroisoquinolines, and indolines in O2-containing suspensions of a commercially available titanium dioxide photocatalyst yielding the corresponding heteroarenes is presented. 4-Amino-2,2,6,6-tetramethylpipiridinyloxyl (4-amino-TEMPO) was found to exhibit a beneficial role, as it increased the yield and improved the selectivity of the dehydrogenation reaction. Both the selectivity and the yield are further enhanced by grafting 0.1 wt % of Ni(II) ions onto the TiO2 surface. It is proposed that the basic reactant adsorbs at Lewis acid sites present at the TiO2 surface. The dehydrogenation reaction is initiated by visible-light excitation of the resulting surface complex and a subsequent single-electron transfer from the excited N-heterocycle via the conduction band of TiO2 to O2. Ni(II) ions possibly serve as an electron transfer bridge between the conduction band of TiO2 and O2, while the TEMPO derivative is assumed to act as a selective redox mediator involved in reactions of the generated reactive oxygen species.
- Balayeva, Narmina O.,Zheng, Nan,Dillert, Ralf,Bahnemann, Detlef W.
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p. 10694 - 10704
(2019/11/14)
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- Metal organic complex and application thereof in organic electronic devices
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The invention relates to a metal organic complex and an application thereof in organic electronic devices. The metal organic complex has a structural general formula represented as a chemical formula(1). The metal organic complex is good in stability, high in light emitting efficiency and simple in synthesis.
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Paragraph 0266; 0267; 0268; 0269
(2019/04/26)
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- Enabling Catalytic Arene C-H Amidomethylation via Bis(tosylamido)methane as a Sustainable Formaldimine Releaser
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Addition of catalytic arene C-H to formaldimines has been enabled by Ru(II)-catalyzed amidomethylation with bis(tosylamido)methane as a catalytic formaldimine releaser. The new process provides an atom-efficient and sustainable solution to address the challenges of formaldimines in this type of transformation. Furthermore, new synthetic routes based on this catalytic system have been developed for step-efficient access to N-heterotricyclic core structures that are pharmaceutically relevant.
- Li, Zhong-Yuan,Chaminda Lakmal, Hetti Handi,Cui, Xin
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supporting information
p. 3735 - 3740
(2019/05/24)
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- Visible Light Induced Rhodium(I)-Catalyzed C?H Borylation
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An efficient visible light induced rhodium(I)-catalyzed regioselective borylation of aromatic C?H bonds is reported. The photocatalytic system is based on a single NHC?RhI complex capable of both harvesting visible light and enabling the bond breaking/forming at room temperature. The chelating nature of the NHC-carboxylate ligand was critical to ensure the stability of the RhI complex and to provide excellent photocatalytic activities. Experimental mechanistic studies evidenced a photooxidative ortho C?H bond addition upon irradiation with blue LEDs, leading to a cyclometalated RhIII-hydride intermediate.
- Thongpaen, Jompol,Manguin, Romane,Dorcet, Vincent,Vives, Thomas,Duhayon, Carine,Mauduit, Marc,Baslé, Olivier
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supporting information
p. 15244 - 15248
(2019/10/22)
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- Site-Selective C–H Functionalization of (Hetero)Arenes via Transient, Non-symmetric Iodanes
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Fosu, Hambira, and colleagues describe the direct C–H functionalization of medicinally relevant arenes or heteroarenes. This strategy is enabled by transient generation of reactive, non-symmetric iodanes from anions and PhI(OAc)2. The site-selective incorporation of Cl, Br, OMs, OTs, and OTf to complex molecules, including within medicines and natural products, can be conducted by the operationally simple procedure included herein. A computational model for predicting site selectivity is also included. The discovery of new medicines is a time- and labor-intensive process that frequently requires over a decade to complete. A major bottleneck is the synthesis of drug candidates, wherein each complex molecule must be prepared individually via a multi-step synthesis, frequently requiring a week of effort per molecule for thousands of candidates. As an alternate strategy, direct, post-synthetic functionalization of a lead candidate could enable this diversification in a single operation. In this article, we describe a new method for direct manipulation of drug-like molecules by incorporation of motifs with either known pharmaceutical value (halides) or that permit subsequent conversion (pseudo-halides) to medicinally relevant analogs. This user-friendly strategy is enabled by combining commercial iodine reagents with salts and acids. We expect this simple method for selective, post-synthetic incorporation of molecular diversity will streamline the discovery of new medicines. A strategy for C–H functionalization of arenes and heteroarenes has been developed to allow site-selective incorporation of various anions, including Cl, Br, OMs, OTs, and OTf. This approach is enabled by in situ generation of reactive, non-symmetric iodanes by combining anions and bench-stable PhI(OAc)2. The utility of this mechanism is demonstrated via para-selective chlorination of medicinally relevant arenes, as well as site-selective C–H chlorination of heteroarenes. Spectroscopic, computational, and competition experiments describe the unique nature, reactivity, and selectivity of these transient, unsymmetrical iodanes.
- Fosu, Stacy C.,Hambira, Chido M.,Chen, Andrew D.,Fuchs, James R.,Nagib, David A.
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supporting information
p. 417 - 428
(2019/02/14)
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- Dark red phosphorescent iridium complex and organic electroluminescent device thereof
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The invention relates to a dark red phosphorescent iridium complex and an organic electroluminescent device thereof, and in particular relates to a dark red-to-near infrared iridium complex phosphorescent luminescent material with a first ligand of 1-phenylisoquinoline derivative, and an auxiliary ligand of amidiniumguanidino derivative, and an organic electroluminescent device prepared from the same, wherein the general structural formula is as shown in the specification. The compound has the advantages that the preparation process is simple, and the prepared electroluminescent device is highin efficiency and long in service life and can be used in flat panel display, illumination, light sources and other applications.
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Paragraph 0020
(2019/03/29)
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- Acceptorless Dehydrogenation of N-Heterocycles and Secondary Alcohols by Ru(II)-NNC Complexes Bearing a Pyrazoyl-indolyl-pyridine Ligand
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Ruthenium(II) hydride complexes bearing a pyrazolyl-(2-indol-1-yl)-pyridine ligand were synthesized and structurally characterized by NMR analysis and X-ray single crystal crystallographic determinations. These complexes efficiently catalyzed acceptorless dehydrogenation of N-heterocycles and secondary alcohols, respectively, exhibiting highly catalytic activity with a broad substrate scope. The present work has established a strategy to construct highly active transition metal complex catalysts and provides an atom-economical and environmentally benign protocol for the synthesis of aromatic N-heterocyclic compounds and ketones.
- Wang, Qingfu,Chai, Huining,Yu, Zhengkun
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p. 584 - 591
(2018/03/08)
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- Metal-Free Dehydrogenation of N-Heterocycles by Ternary h-BCN Nanosheets with Visible Light
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An efficient metal-free catalytic system has been developed based on hexagonal boron carbon nitride (h-BCN) nanosheets for the dehydrogenation of N-heterocycles with visible light; hydrogen gas is released in the process, and thus no proton acceptor is needed. This acceptorless dehydrogenation of hydroquinolines, hydroisoquinolines, and indolines to the corresponding aromatic N-heterocycles occurred in excellent yield under visible-light irradiation at ambient temperature. With h-BCN as the photocatalyst and water as the solvent, this environmentally benign protocol shows broad substitution tolerance and high efficiency.
- Zheng, Meifang,Shi, Jiale,Yuan, Tao,Wang, Xinchen
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supporting information
p. 5487 - 5491
(2018/04/02)
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- Transition-Metal-Free Decarboxylative Arylation of 2-Picolinic Acids with Arenes under Air Conditions
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A facile, transition-metal-free, and direct decarboxylative arylation of 2-picolinic acids with simple arenes is described. The oxidative decarboxylative arylation of 2-picolinic acids with arenes proceeds readily via N-chloro carbene intermediates to afford 2-arylpyridines in satisfactory to good yields under transition-metal-free conditions. This new type of decarboxylative arylation is operationally simple and scalable and exhibits high functional-group tolerance. Various synthetically useful functional groups, such as halogen atoms, methoxycarbonyl, and nitro, remain intact during the decarboxylative arylation of 2-picolinic acids.
- Zhang, Xitao,Feng, Xiujuan,Zhou, Chuancheng,Yu, Xiaoqiang,Yamamoto, Yoshinori,Bao, Ming
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supporting information
p. 7095 - 7099
(2018/11/23)
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- Intramolecular Desulfitative Coupling: Nickel-Catalyzed Transformation of Diaryl Sulfones into Biaryls via Extrusion of SO2
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As a new transformation of organosulfur compounds, intramolecular desulfitative coupling of diaryl sulfones to the corresponding biaryls has been developed with the aid of nickel-NHC catalysts. This catalytic elimination of SO2 was also applicable to alkenyl aryl sulfone to furnish the corresponding alkenyl arene.
- Takahashi, Fumiya,Nogi, Keisuke,Yorimitsu, Hideki
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p. 6601 - 6605
(2018/10/20)
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- Transition-Metal-Free C-H Arylation of Unactivated Arenes with 8-Hydroxyquinoline as a Promoter
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A method for the transition-metal-free direct C-H arylation of unactivated arenes is developed with aryl bromides as substrates and 8-hydroxyquinoline as an efficient promoter. A variety of biaryl compounds with structural diversity are obtained in moderate to high yields. Mechanistic studies reveal that the reaction proceeds via a homolytic aromatic substitution pathway.
- Zheng, Xuehua,Wu, Xu-Nian,Chen, Jing-Yi,Luo, Hai-Bin,Wu, Deyan,Wu, Yinuo
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p. 1721 - 1727
(2018/02/06)
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- Accessing Heterobiaryls through Transition-Metal-Free C-H Functionalization
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Herein we report a transition-metal-free synthetic protocol for heterobiaryls, one of the most important pharmacophores in the modern drug industry, employing a new multidonor phenalenyl (PLY)-based ligand. The current procedure offers a wide substrate scope (24 examples) with a low catalyst loading resulting in an excellent product yield (up to 95%). The reaction mechanism involves a single electron transfer (SET) from a phenalenyl-based radical to generate a reactive heteroaryl radical. To establish the mechanism, we have isolated the catalytically active SET initiator, characterizing by a magnetic study.
- Banik, Ananya,Paira, Rupankar,Shaw, Bikash Kumar,Vijaykumar, Gonela,Mandal, Swadhin K.
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p. 3236 - 3244
(2018/03/23)
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- Graphene oxide-phenalenyl composite: transition metal-free recyclable and catalytic C-H functionalization
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An efficient route towards a heterogeneous transition metal-free catalytic C-H functionalization using a covalently linked graphene oxide-phenalenyl conjugate is described herein (28 examples, which include a core of some biologically relevant biaryl and hetero-biaryls). It is an environmentally benign, economical and heterogeneous platform, whose catalytic activity can easily be regenerated through a simple washing-drying technique and the catalytic activity can be retained even after 10 cycles.
- Singh, Bhagat,Paira, Rupankar,Biswas, Goutam,Shaw, Bikash Kumar,Mandal, Swadhin K.
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supporting information
p. 13220 - 13223
(2018/12/10)
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- Suzuki-Miyaura cross-coupling for efficient synthesis of aryl-substituted N-heteroarenes catalyzed by recyclable N-phenylpiperazine-Palladium(II) complex
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Polystyrene supported N-phenylpiperazine-Pd(II) complex D was synthesized and characterized by various techniques, including Fourier transform infrared spectroscopy (FTIR), scanning electronmicroscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and thermal analysis (TG-DTA). This heterogeneous Pd(II) complex showed high catalytic efficiency for the Suzuki-Miyaura coupling of arylboronic acids with aryl bromides, aryl chlorides to give the corresponding 2-arylpyridines and heteroarenes. The coupled products were formed in excellent yields at low catalyst loadings under mild reaction conditions. Further, this heterogeneous catalyst showed excellent recyclability and reused for four cycles with no significant decrease in its activity.
- Perumgani, Pullaiah C.,Kodicherla, Balaswamy,Mandapati, Mohan Rao,Parvathaneni, Sai Prathima
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supporting information
p. 227 - 232
(2018/04/02)
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- Directed: Ortho C-H borylation catalyzed using Cp?Rh(iii)-NHC complexes
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Cp?Rh(NHC) complexes with bulky chiral bidentate NHC-carboxylate ligands were efficiently synthesized and fully characterized including solid-state structures. These unprecedented rhodium(iii) complexes demonstrated high selectivity in pyridine-directed ortho-C-H borylation of arenes under mild conditions.
- Thongpaen, Jompol,Schmid, Thibault E.,Toupet, Loic,Dorcet, Vincent,Mauduit, Marc,Baslé, Olivier
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supporting information
p. 8202 - 8205
(2018/07/29)
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- Ir(III) complex-based phosphorescence and electrochemiluminescence chemodosimetric probes for Hg(II) ions with high selectivity and sensitivity
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Mercury, one of the most prevalent toxic metal elements, poses severe risks to human health and the environment. Several molecular probes have been developed for colorimetric and fluorometric detection of Hg(ii) ions. Nevertheless, development of a rapid, selective, and sensitive probe for Hg(ii) ions remains important. Herein, we report three Ir(iii) complex-based phosphorescence and electrochemiluminescence chemodosimeters for the selective detection of Hg(ii) ions. The acetylacetonate ancillary ligand of probe 1 reacts selectively with the Hg(ii) ion, inducing phosphorescence enhancement with a concomitant blue-shift. Meanwhile, the Hg(ii) ion selectively quenches the phosphorescence of probe 2. Probes 1 and 2 showed low detection limits (LOD) of 73 and 160 nM, respectively. In addition, the Hg(ii) ion level was successfully monitored by the electrochemiluminescence decrement of probe 9 with a good linear correlation between 0 and 40 μM, with a detection limit of 170 pM.
- Rhee, Hayoung,Kim, Taemin,Hong, Jong-In
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p. 3803 - 3810
(2018/03/21)
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- C6-Selective Direct Arylation of 2-Phenylpyridine via an Activated N-methylpyridinium Salt: A Combined Experimental and Theoretical Study
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An elegant pre-activation strategy, based on the formation of N-methylpyridinium iodide salts for C6-selective direct arylation of 2-phenylpyridines using Pd/Cu cooperative catalysis, has been developed. By this methodology, a wide range of unsymmetrical 2, 6-diarylpyridines were synthesized with high reactivity and regioselectivity as well as good functional group tolerance. In particular, challenging substrates bearing electron donating groups (EDGs), such as OMe, NMe2, were also successfully employed in this reaction. Deuterium incorporation studies revealed that the C?H bond acidity is improved significantly in N-methylpyridinium salts compared with their N-Oxide and N-iminopyridinium ylide counterparts, thus solving the long-standing problem associated with previous strategies for the synthesis of diaryl pyridines. Finally, the control experiments and DFT calculations supported a Pd-catalyzed and Cu-mediated mechanism in which a carbenoid copper species that is formed in-situ from N-methylpyridinium salts, participates in a Pd-catalyzed arylation followed by an iodide-promoted N-demethylation process. (Figure presented.).
- Yin, Changzhen,Zhong, Kangbao,Li, Wenjing,Yang, Xiao,Sun, Rui,Zhang, Chunchun,Zheng, Xueli,Yuan, Maolin,Li, Ruixiang,Lan, Yu,Fu, Haiyan,Chen, Hua
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supporting information
p. 3990 - 3998
(2018/09/12)
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- Red light metal complex, preparation method and application thereof
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The invention belongs to the field of organic electroluminescence materials, and discloses a red light metal complex formed by using an alkyl-substituted phenylisoquinoline derivative as a main ligand, a preparation method and an application thereof. Different alkyl substituents are introduced on the main ligand, purification and sublimation yields of a material are remarkably improved, so using cost of the material is effectively reduced, and it is extremely beneficial to industrial production. In addition, because of the steric-hindrance effect of an increased alkyl chain, steric hindrance of molecules is enhanced, so a luminescence quenching situation is relieved, and luminous efficiency is improved.
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Paragraph 0106-0108
(2019/01/15)
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- Hybrid Catalysis Enabling Room-Temperature Hydrogen Gas Release from N-Heterocycles and Tetrahydronaphthalenes
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Hybrid catalyst systems to achieve acceptorless dehydrogenation of N-heterocycles and tetrahydronaphthalenes-model substrates for liquid organic hydrogen carriers-were developed. A binary hybrid catalysis comprising an acridinium photoredox catalyst and a Pd metal catalyst was effective for the dehydrogenation of N-heterocycles, whereas a ternary hybrid catalysis comprising an acridinium photoredox catalyst, a Pd metal catalyst, and a thiophosphoric imide organocatalyst achieved dehydrogenation of tetrahydronaphthalenes. These hybrid catalyst systems allowed for 2 molar equiv of H2 gas release from six-membered N-heterocycles and tetrahydronaphthalenes under mild conditions, i.e., visible light irradiation at rt. The combined use of two or three different catalyst types was essential for the catalytic activity.
- Kato, Shota,Saga, Yutaka,Kojima, Masahiro,Fuse, Hiromu,Matsunaga, Shigeki,Fukatsu, Arisa,Kondo, Mio,Masaoka, Shigeyuki,Kanai, Motomu
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supporting information
p. 2204 - 2207
(2017/02/23)
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- Cyclometalated ruthenium complex as well as synthetic method and application thereof
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The invention provides a cyclometalated ruthenium complex as well as a synthetic method and application thereof. The cyclometalated ruthenium complex has a chemical general formula of [Ru(L)2(PhIQ-R)](PF6), wherein PhIQ-R serves as a main ligand; when R is equal to H, PhIQ-R refers to 1-phrnyl-isoquinoline; when R is equal to Me, PhIQ-R refers to 1-p-methylphenyl-isoquinoline; and L is an auxiliary ligand and is preferably selected from 2,2-dipyridyl or phenanthroline. The cyclometalated ruthenium complex [Ru(L)2(PhIQ-R)](PF6) has more excellent antitumor activity than cis-platinum and is easily synthesized; and the cyclometalated ruthenium complex disclosed by the invention has excellent antitumor activity and the advantages of transmembrane simplicity, high targeting property and low toxicity, is applied to preparing various anti-cancer drugs or DNA insertion agents and has excellent clinical application prospects.
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- Method for solvent accelerated selective dehydrogenation of tetrahydroisoquinoline type compound
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The invention discloses a method for synthesizing 1-substituted-3,4-dihydroisoquinoline through the solvent accelerated selective partial dehydrogenation of a 1-substituted-1,2,3,4-tetrahydroisoquinoline compound. For a simple and easily obtained cyclic amine type compound such as a tetrahydroisoquinoline compound, a corresponding imine compound can be obtained through selective dehydrogenation; the conversion ratio of the cyclic amine type compound is higher; further, the proportion of a partially dehydrogenated product to a fully dehydrogenated product is more than 20 to 1. The method is simple and convenient to operate, is practical, easy and feasible, and is mild in reaction condition; the actual cost is greatly reduced. In addition, a method for synthesizing 3,4-dihydroisoquinoline through the direct dehydrogenation of tetrahydroisoquinoline has the advantages of atom economy and environmental friendliness.
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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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- Inhibitors of the detoxifying enzyme of the phytoalexin brassinin based on quinoline and isoquinoline scaffolds
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The detoxification of the phytoalexin brassinin to indole-3-carboxaldehyde and S-methyl dithiocarbamate is catalyzed by brassinin oxidase (BOLm), an inducible fungal enzyme produced by the plant pathogen Leptosphaeria maculans. Twenty-six substituted quinolines and isoquinolines are synthesized and evaluated for antifungal activity against L. maculans and inhibition of BOLm. Eleven compounds that inhibit BOLm activity are reported, of which 3-ethyl-6-phenylquinoline displays the highest inhibitory effect. In general, substituted 3-phenylquinolines show significantly higher inhibitory activities than the corresponding 2-phenylquinolines. Overall, these results indicate that the quinoline scaffold is a good lead to design paldoxins (phytoalexin detoxification inhibitors) that inhibit the detoxification of brassinin by L. maculans.
- Pedras, M. Soledade C.,Abdoli, Abbas,Sarma-Mamillapalle, Vijay K.
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- Synthesis, photophysical, electrochemical and electroluminescence studies of red emitting phosphorescent Ir(III) heteroleptic complexes
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Abstract: Five heteroleptic, cyclometalated (C∧N) Iridium(III) complexes of acetylacetone (acac) and 1-phenyl-isoquinoline (piq) derivatives, Ir(acac)(piq)2, Ir(acac)(2,4-difluoro-piq)2, Ir(acac)(4-trifluoromethyl-piq)2, Ir(acac)(4-N,N-dimethyl-piq)2, Ir(acac)(4-acetyl-piq)2, were synthesized and characterized. The (C ∧N ) 2Ir(acac) complexes in toluene showed phosphorescence (λ max= 598 nm to 658 nm) with quantum yields (0.1 to 0.32) and microsecond lifetimes (0.43 to 1.9 μ s). The complexes were non-luminescent in thin films due to self-quenching but luminescent when lightly doped (5%) in a host organic material, 4,4′-Bis(N-carbazolyl)-1,1′-biphenyl (CBP). The HOMO levels determined using cyclic voltammetric oxidation potentials were in the range ?5.48 to ?5.80 eV. Electroluminescence properties and performance of the Ir complexes doped in CBP (active layer) were studied in a multilayer (ITO/F4TCNQ/TPD/doped CBP/BCP/LiF/Al) organic light emitting device (OLED). The electroluminescense (EL) spectra of the device matched with the phosphorescent spectra of the Ir complexes. The turn-on voltage at ~ 4.5 V, maximum brightness of 7600 cd/m 2 and current efficiency of ~ 7.0 cd/A at a brightness of ~ 100 cd/m 2 indicate that these are promising OLED materials. GRAPHICAL ABSTRACT: Synopsis. Heteroleptic, cyclometalated (C∧N) Iridium(III) complexes of acetylacetone (acac) and 1-phenyl-isoquinoline were synthesized and their photophysical, electrochemical and electroluminescence properties were studied. The OLED of Ir complex as emitting material showed turn-on voltage at ~ 4.5 V, maximum brightness of 7600 cd/m 2 and current efficiency of ~ 7.0 cd/A at a brightness of ~ 100 cd/m 2.[Figure not available: see fulltext.].
- Ali, Farman,Nayak, Pabitra K,Periasamy,Agarwal, Neeraj
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p. 1391 - 1398
(2017/09/25)
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- Enantioselective, Copper-Catalyzed Alkynylation of Ketimines to Deliver Isoquinolines with α-Diaryl Tetrasubstituted Stereocenters
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An enantioselective, copper-catalyzed alkynylation of cyclic α,α-diaryl ketiminium ions has been developed to deliver isoquinoline products with diaryl, tetrasubstituted stereocenters. The success of this reaction relied on identification of Ph-PyBox as the optimal ligand, i-Pr2NEt as the base, and CHCl3 as the solvent. A broad scope and functional group tolerance were observed. Notably, the use of both aryl and silyl acetylenes results in high yields and enantioselectivities. Mechanistic experiments are consistent with a dimeric or higher order catalyst.
- Dasgupta, Srimoyee,Liu, Jixin,Shoffler, Clarissa A.,Yap, Glenn P. A.,Watson, Mary P.
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supporting information
p. 6006 - 6009
(2016/12/09)
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- General copper-catalyzed coupling of alkyl-, aryl-, and alkynylaluminum reagents with organohalides
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We report the first example of a very general Cu-catalyzed cross-coupling of organoaluminum reagents with organohalides. The reactions proceed for the couplings of alkyl-, aryl-, and alkynylaluminum reagents with aryl and heteroaryl halides and vinyl bromides, affording the cross-coupled products in good to excellent yields. Both primary and secondary alkylaluminum reagents can be utilized as organometallic coupling partners. These reactions are not complicated by β-hydride elimination, and as a result rearranged products are not observed with secondary alkylaluminum reagents even for couplings with heteroaryl halides under "ligand-free" conditions. Radical clock experiment with a radical probe and relative reactivity study of Ph3Al with two haloarenes, 1-bromonaphthalene and 4-chlorobenzonitrile, having two different redox potentials indicates that the reaction does not involve free aryl radicals and radical anions as intermediates. These results combined with the result of the Hammett plot obtained by reacting Ph3Al with iodoarenes containing p-H, p-Me, p-F, and p-CF3 substituents, which shows a linear curve (R2 = 0.99) with a ρ value of +1.06, suggest that the current transformation follows an oxidative addition-reductive elimination pathway.
- Shrestha, Bijay,Thapa, Surendra,Gurung, Santosh K.,Pike, Ryan A. S.,Giri, Ramesh
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p. 787 - 802
(2016/02/18)
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- A new approach to 1-substituted β-carbolines and isoquinolines utilizing tributyl[(Z)-2-ethoxyvinyl]stannane as a C-3,C-4 building block
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Starting from readily available indole-2-carboxylic acids, 1-substituted β-carbolines (among them the alkaloids harmane and isoharmine) are readily obtained via the corresponding 2-acylindoles, bromination at C-3, followed by a one-pot Stille cross-coupling with tributyl[(Z)-2-ethoxyvinyl]stannane, and ring closure with ammonium acetate. 1-Substituted isoquinolines are available in an analogous manner starting from 2-bromobenzoic acid.
- Kamlah, Alexandra,Lirk, Florian,Bracher, Franz
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p. 837 - 845
(2016/01/20)
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- Palladium carbon catalyzed selective partial dehydrogenation method of tetrahydroisoquinoline
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The invention relates to a method for synthesis of 1-substituted-3, 4-dihydroisoquinoline by palladium carbon catalyzed selective partial dehydrogenation of a 1-substituted-1, 2, 3, 4-tetrahydroisoquinoline compound. The reaction temperature is 0-80DEG C. For easily available cyclic amine compounds like tetrahydroisoquinoline, a corresponding imine compound can be obtained through selective dehydrogenation, the conversion rate is up to 99%, and the proportion of a partial dehydrogenation product and a complete dehydrogenation product is greater than 20:1. The method provided by the invention has simple and practical operation, the raw materials and catalyst are cheap and easily available, the reaction conditions are mild, and the catalyst can be recycled, thus greatly reducing the actual cost. In addition, the method for synthesis of 3, 4-dihydroisoquinoline through direct dehydrogenation of tetrahydroisoquinoline has the advantages of atom economy and environmental friendliness.
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Paragraph 0036; 0037; 0040
(2017/02/09)
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- Highly selective partial dehydrogenation of tetrahydroisoquinolines using modified Pd/C
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A highly selective procedure has been developed for the partial dehydrogenation of 1-substituted-1,2,3,4-tetrahydroisoquinolines over K3PO4·3H2O-modified Pd/C catalyst. This new method provides facile, atom-economical and environmentally friendly access to 1-substituted-3,4-dihydroisoquinolines without the need for stoichiometric amounts of harmful oxidants. The use of standard Pd/C as a catalyst for this process gave poor chemoselectivity. Pleasingly, the use of a K3PO4·3H2O-modified Pd/C catalyst promoted the partial dehydrogenation of 1-substituted-1,2,3,4-tetrahydroisoquinolines with excellent chemoselectivity by suppressing further dehydroaromatization. Furthermore, conducting the reaction under an atmosphere of oxygen led to further improvements in the chemoselectivity of the dehydrogenation, with the ratio of imine to isoquinoline reaching up to 32/1. The heterogenous Pd/C catalyst could also be recycled and reused at least three times with excellent conversion and chemoselectivity, demonstrating the significantly practical potential of this methodology.
- Ji, Yue,Chen, Mu-Wang,Shi, Lei,Zhou, Yong-Gui
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- Ligand-Free Copper-Catalyzed Negishi Coupling of Alkyl-, Aryl-, and Alkynylzinc Reagents with Heteroaryl Iodides
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Reported herein is an unprecedented ligand-free copper-catalyzed cross-coupling of alkyl-, aryl-, and alkynylzinc reagents with heteroaryl iodides. The reaction proceeds at room temperature for the coupling of primary, secondary, and tertiary alkylzinc reagents with heteroaryl iodides without rearrangement. An elevated temperature (100 C) is required for aryl-heteroaryl and alkynyl-heteroaryl couplings.
- Thapa, Surendra,Kafle, Arjun,Gurung, Santosh K.,Montoya, Adam,Riedel, Patrick,Giri, Ramesh
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supporting information
p. 8236 - 8240
(2015/07/07)
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- A Pd(ii)/Mg-La mixed oxide catalyst for cyanation of aryl C-H bonds and tandem Suzuki-cyanation reactions
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A palladium(ii)/magnesium-lanthanum mixed oxide (Pd(ii)/Mg-La) catalyst is a reusable catalyst for cyanation of aromatic C-H bonds by using the combination of NH4HCO3 and DMSO as the ''CN'' source. Moderate to good yields of aromatic nitriles were obtained. An excellent regioselectivity was achieved using the present protocol. A tandem process involving Suzuki coupling followed by a cyanation reaction was also developed using the heterogeneous (Pd(ii)/Mg-La) catalyst. This cascade process resulted in the formation of aromatic nitrile from simple 2-halopyridine. The catalyst was recovered by centrifugation and reused for three consecutive cycles with nearly consistent activity and selectivity. This journal is
- Kishore, Ramineni,Yadav, Jagjit,Venu, Boosa,Venugopal, Akula,Lakshmi Kantam
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supporting information
p. 5259 - 5264
(2015/07/07)
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