- Iron-Catalyzed ?±,?-Dehydrogenation of Carbonyl Compounds
-
An iron-catalyzed α,β-dehydrogenation of carbonyl compounds was developed. A broad spectrum of carbonyls or analogues, such as aldehyde, ketone, lactone, lactam, amine, and alcohol, could be converted to their α,β-unsaturated counterparts in a simple one-step reaction with high yields.
- Zhang, Xiao-Wei,Jiang, Guo-Qing,Lei, Shu-Hui,Shan, Xiang-Huan,Qu, Jian-Ping,Kang, Yan-Biao
-
supporting information
p. 1611 - 1615
(2021/03/03)
-
- Monomeric vanadium oxide: A very efficient species for promoting aerobic oxidative dehydrogenation of N-heterocycles
-
Monomeric active species are very interesting in heterogeneous catalysis. In this work, we proposed a method to prepare VOx-NbOy@C catalysts, which involve the one-pot hydrothermal synthesis of inorganic/organic hybrid materials containing V/Nb followed by thermal treatment under a reducing atmosphere. The prepared catalysts were characterized using different techniques, such as high-angle annular dark-field scanning transmission electron microscopy and X-ray absorption fine structure spectroscopy. It was shown that monomeric VOx species were dispersed homogeneously in the catalysts. The VOx-NbOy@C catalysts displayed high performance in the aerobic oxidative dehydrogenation of N-heterocycles to aromatic heterocycles. It was demonstrated that the selectivity of reaction over the catalyst with a very small amount of V (0.07 wt%) was much higher than that over the NbOy@C, and the catalyst also exhibited excellent stability in the reaction. The detailed study indicated that monomeric VO2 species were the most effective for promoting the reaction. This journal is
- Xie, Zhenbing,Chen, Bingfeng,Zheng, Lirong,Peng, Fangfang,Liu, Huizhen,Han, Buxing
-
p. 431 - 437
(2021/01/11)
-
- Highly Ordered Mesoporous Cobalt Oxide as Heterogeneous Catalyst for Aerobic Oxidative Aromatization of N-Heterocycles
-
N-heterocycles are key structures for many pharmaceutical intermediates. The synthesis of such units normally is conducted under homogeneous catalytic conditions. Among all methods, aerobic oxidative aromatization is one of the most effective. However, in homogeneous conditions, catalysts are difficult to be recycled. Herein, we report a heterogeneous catalytic strategy with a mesoporous cobalt oxide as catalyst. The developed protocol shows a broad applicability for the synthesis of N-heterocycles (32 examples, up to 99 % yield), and the catalyst presents high turnover numbers (7.41) in the absence of any additives. Such a heterogenous approach can be easily scaled up. Furthermore, the catalyst can be recycled by simply filtration and be reused for at least six times without obvious deactivation. Comparative studies reveal that the high surface area of mesoporous cobalt oxide plays an important role on the catalytic reactivity. The outstanding recycling capacity makes the catalyst industrially practical and sustainable for the synthesis of diverse N-heterocycles.
- Cao, Yue,Wu, Yong,Zhang, Yuanteng,Zhou, Jing,Xiao, Wei,Gu, Dong
-
p. 3679 - 3686
(2021/06/18)
-
- Visible-light-mediated organoboron-catalysed metal-free dehydrogenation of N-heterocycles using molecular oxygen
-
The surge of photocatalytic transformation not only provides unprecedented synthetic methods, but also triggers the enthusiasm for more sustainable photocatalysts. On the other hand, oxygen is an ideal oxidant in terms of atom economy and environmental friendliness. However, the poor reactivity of oxygen at the ground state makes its utilization challenging. Herein, a visible-light-induced oxidative dehydrogenative process is disclosed, which uses an organoboron compound as the photocatalyst and molecular oxygen as the sole oxidant.Viathis approach, an array of N-heterocycles have been accessed under metal-free mild conditions, in good to excellent yields.
- Wei, Lanfeng,Wei, Yu,Xu, Liang,Zhang, Jinli
-
supporting information
p. 4446 - 4450
(2021/06/30)
-
- Geometric and electronic effects on the performance of a bifunctional Ru2P catalyst in the hydrogenation and acceptorless dehydrogenation of N-heteroarenes
-
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
-
p. 1185 - 1194
(2021/02/16)
-
- Metal-Free Deoxygenation of Amine N-Oxides: Synthetic and Mechanistic Studies
-
We report herein an unprecedented combination of light and P(III)/P(V) redox cycling for the efficient deoxygenation of aromatic amine N-oxides. Moreover, we discovered that a large variety of aliphatic amine N-oxides can easily be deoxygenated by using only phenylsilane. These practically simple approaches proceed well under metal-free conditions, tolerate many functionalities and are highly chemoselective. Combined experimental and computational studies enabled a deep understanding of factors controlling the reactivity of both aromatic and aliphatic amine N-oxides.
- Lecroq, William,Schleinitz, Jules,Billoue, Mallaury,Perfetto, Anna,Gaumont, Annie-Claude,Lalevée, Jacques,Ciofini, Ilaria,Grimaud, Laurence,Lakhdar, Sami
-
p. 1237 - 1242
(2021/06/01)
-
- Highly chemoselective deoxygenation of N-heterocyclic: N -oxides under transition metal-free conditions
-
Because their site-selective C-H functionalizations are now considered one of the most useful tools for synthesizing various N-heterocyclic compounds, the highly chemoselective deoxygenation of densely functionalized N-heterocyclic N-oxides has received much attention from the synthetic chemistry community. Here, we provide a protocol for the highly chemoselective deoxygenation of various functionalized N-oxides under visible light-mediated photoredox conditions with Na2-eosin Y as an organophotocatalyst. Mechanistic studies imply that the excited state of the organophotocatalyst is reductively quenched by Hantzsch esters. This operationally simple technique tolerates a wide range of functional groups and allows high-yield, multigram-scale deoxygenation. This journal is
- Kim, Se Hyun,An, Ju Hyeon,Lee, Jun Hee
-
supporting information
p. 3735 - 3742
(2021/05/04)
-
- MnOx/catechol/H2O: A cooperative catalytic system for aerobic oxidative dehydrogenation of N-heterocycles at room temperature
-
Amorphous manganese oxide doped by Na+ ion (Na-AMO) was successfully prepared and found to be an efficient heterogeneous catalyst in aerobic oxidative dehydrogenation of N-heterocycles, cooperate with catechol. Na-AMO was fully characterized by XRD, XPS BET H2-TPR, CO2-TPD FT-IR, TEM, SEM and had rich amounts of surface absorbed active oxygen species which are responsible for superior catalytic performance. The synergistic interaction between Na-AMO and catechol makes catalytic system efficient and tolerant, which offers various N-heterocycles in good to excellent yields under mild conditions.
- Tang, Tao,Bi, Xiuru,Meng, Xu,Chen, Gexin,Gou, Mingxia,Liu, Xiang,Zhao, Peiqing
-
-
- NCP-Type Pincer Iridium Complexes Catalyzed Transfer-Dehydrogenation of Alkanes and Heterocycles?
-
A series of NCP-type pincer iridium complexes, (RNCCP)IrHCl (2a—2c) and (BQ-NCOP)IrHCl 3, have been studied for catalytic transfer alkane dehydrogenation. Complex 3 containing a rigid benzoquinoline backbone exhibits high activity and robustness in dehydrogenation of alkanes to form alkenes. Even more importantly, this catalyst system was also highly effective in the dehydrogenation of a wide range of heterocycles to furnish heteroarenes.
- Wang, Yulei,Qian, Lu,Huang, Zhidao,Liu, Guixia,Huang, Zheng
-
supporting information
p. 837 - 841
(2020/05/18)
-
- Rh/TiO2-Photocatalyzed Acceptorless Dehydrogenation of N-Heterocycles upon Visible-Light Illumination
-
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
-
p. 5542 - 5553
(2020/08/25)
-
- Visible-Light-Promoted Efficient Aerobic Dehydrogenation of N-Heterocycles by a Tiny Organic Semiconductor Under Ambient Conditions
-
An efficient reusable catalytic system has been developed based on perylene diimide (PDI) organic semiconductor for the aerobic dehydrogenation of N-heterocycles with visible light. This practical catalytic system without any additives proceeds under ambient conditions. The minute aggregates of PDI molecules on the surface of SiO2 nanospheres form tiny organic semiconductors, resulting in high-efficiency photo-oxidative activity. Notably, the robustness of this method is demonstrated by the synthesis of a wide range of N-heteroarenes, gram-scale experiments as well as reusability tests.
- Su, Chenliang,Yu, Kunyi,Zhang, Hanjie,Zhu, Yongfa
-
supporting information
p. 1956 - 1960
(2020/04/10)
-
- DMSO/t-BuONa/O2-Mediated Aerobic Dehydrogenation of Saturated N-Heterocycles
-
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
-
p. 7501 - 7509
(2020/07/07)
-
- Catalytic Aerobic Dehydrogenatin of N-Heterocycles by N-Hydoxyphthalimide
-
Catalytic methods for the aerobic dehydrogenation of N-heterocycles are reported. In most cases, indoles are accessed efficiently from indolines using catalytic N-hydroxyphthalimide (NHPI) as the sole additive under air. Further studies revealed an improved catalytic system of NHPI and copper for the preparation of other heteroaromatics, for example quinolines. (Figure presented.).
- Chen, Weidong,Tang, Hao,Wang, Weilin,Fu, Qiang,Luo, Junfei
-
supporting information
p. 3905 - 3911
(2020/08/10)
-
- Method for preparation of quinoline compounds
-
The invention discloses a green preparation method of quinoline compounds. According to the method, cheap and easily available copper salt and N-hydroxyphthalimide are used as catalysts, oxygen is used as an oxidizing agent, oxidation of tetrahydroquinoline compounds is performed in an organic solvent, and synthesis of quinoline compounds is realized. The method has the advantages of simple reaction operation, low reaction cost, high yield, low metal pollution and the like.
- -
-
Paragraph 0049-0051
(2020/11/12)
-
- Aerobic oxidative dehydrogenation of N-heterocycles over OMS-2-based nanocomposite catalysts: Preparation, characterization and kinetic study
-
OMS-2-based nanocomposites doped with tungsten were prepared for the first time and their remarkably enhanced catalytic activity and recyclability in aerobic oxidative dehydrogenation of N-heterocycles were examined in detail. Many tetrahydroquinoline derivatives and a broad range of other N-heterocycles could be tolerated by the catalytic system using a biomass-derived solvent as a reaction medium. Newly generated mixed crystal phases, noticeably enhanced surface areas and labile lattice oxygen of the OMS-2-based nanocomposite catalysts might contribute to their excellent catalytic performance. Moreover, a kinetic study was extensively performed which concluded that the dehydrogenation of 1,2,3,4-tetrahydroquinoline is a first-order reaction, and the apparent activation energy is 29.66 kJ mol-1
- Bi, Xiuru,Tang, Tao,Meng, Xu,Gou, Mingxia,Liu, Xiang,Zhao, Peiqing
-
p. 360 - 371
(2020/02/04)
-
- Reversible aerobic oxidative dehydrogenation/hydrogenation of N-heterocycles over AlN supported redox cobalt catalysts
-
N-heterocycles with quinoline and tetrahydroquinoline structures are highly important in pharmaceutical and chemical industries, and their highly efficient mutual transformations are vital but still challenging. In the present work, AlN supported redox cobalt catalysts (Co3O4/AlN and Co/AlN) were prepared, which could achieve the reversible aerobic oxidative dehydrogenation/hydrogenation of N-heterocycles with good performances. The catalytic performances were stem from the strong interaction between Co species with AlN support, which were confirmed by the characterizations of Raman, XPS, UV–vis DRS, and H2-TPR etc. Both of the catalysts showed good stabilities and reusabilities for the titled reactions. Besides, the gram-scale experiments achieved with good yields to corresponding products, revealing the present protocol possesses great potential applications in industry. The strategy of using redox Co-based catalyst not only provides a potential catalyst for the reversible hydrogenation/oxidative dehydrogenation reactions but also replenishes methods for constructing of other redox catalyst, especially with AlN as a carrier.
- He, Zhen-Hong,Sun, Yong-Chang,Wang, Kuan,Wang, Zhong-Yu,Guo, Pan-Pan,Jiang, Chong-Shan,Yao, Man-Qing,Li, Zhu-Hui,Liu, Zhao-Tie
-
-
- Homologation of the Fischer Indolization: A Quinoline Synthesis via Homo-Diaza-Cope Rearrangement
-
We disclose a new Br?nsted acid promoted quinoline synthesis, proceeding via homo-diaza-Cope rearrangement of N-aryl-N′-cyclopropyl hydrazines. Our strategy can be considered a homologation of Fischer's classical indole synthesis and delivers 6-membered N-heterocycles, including previously inaccessible pyridine derivatives. This approach can also be used as a pyridannulation methodology toward constructing polycyclic polyheteroaromatics. A computational analysis has been employed to probe plausible activation modes and to interrogate the role of the catalyst.
- De, Chandra Kanta,Gerosa, Gabriela Guillermina,List, Benjamin,Maji, Rajat,Schwengers, Sebastian Armin
-
supporting information
p. 20485 - 20488
(2020/09/09)
-
- Exhaustive Reduction of Esters Enabled by Nickel Catalysis
-
We report a one-step procedure to directly reduce unactivated aryl esters into their corresponding tolyl derivatives. This is achieved by an organosilane-mediated ester hydrosilylation reaction and subsequent Ni/NHC-catalyzed hydrogenolysis. The resulting conditions provide a direct and efficient alternative to multi-step procedures for this transformation that often require the use of hazardous metal hydrides. Applications in the synthesis of -CD3-containing products, derivatization of bioactive molecules, and chemoselective reduction in the presence of other C-O bonds are demonstrated.
- Cook, Adam,Prakash, Sekar,Zheng, Yan-Long,Newman, Stephen G.
-
supporting information
p. 8109 - 8115
(2020/05/20)
-
- Nickel/Photoredox-Catalyzed Methylation of (Hetero)aryl Chlorides Using Trimethyl Orthoformate as a Methyl Radical Source
-
Methylation of organohalides represents a valuable transformation, but typically requires harsh reaction conditions or reagents. We report a radical approach for the methylation of (hetero)aryl chlorides using nickel/photoredox catalysis wherein trimethyl orthoformate, a common laboratory solvent, serves as a methyl source. This method permits methylation of (hetero)aryl chlorides and acyl chlorides at an early and late stage with broad functional group compatibility. Mechanistic investigations indicate that trimethyl orthoformate serves as a source of methyl radical via β-scission from a tertiary radical generated upon chlorine-mediated hydrogen atom transfer.
- Kariofillis, Stavros K.,Shields, Benjamin J.,Tekle-Smith, Makeda A.,Zacuto, Michael J.,Doyle, Abigail G.
-
supporting information
p. 7683 - 7689
(2020/04/22)
-
- Superacid-promoted synthesis of quinoline derivatives
-
A series of vinylogous imines have been prepared from anilines and cinnamaldehydes. These substrates react in superacidic media to provide quinolines and related compounds. A mechanism for the conversion is proposed which involves the cyclization of dicationic superelectrophilic intermediates. Aromatization of the quinoline ring is thought to occur by superacid-promoted elimination of benzene.
- Klumpp, Douglas A.,Stentzel, Michael R.,Vuong, Hein
-
supporting information
(2020/01/24)
-
- A Reusable Cobalt Catalyst for Reversible Acceptorless Dehydrogenation and Hydrogenation of N-Heterocycles
-
The development of robust catalytic systems based on base-metals for reversible acceptorless dehydrogenation (ADH) and hydrogenation of feedstock chemicals is very important in the context of ‘hydrogen storage’. Herein, we report a highly efficient reusable cobalt-based heterogeneous catalyst for reversible dehydrogenation and hydrogenation of N-heterocycles. Both the ADH and the hydrogenation processes operate under mild, benign conditions.
- Jaiswal, Garima,Subaramanian, Murugan,Sahoo, Manoj K.,Balaraman, Ekambaram
-
p. 2449 - 2457
(2019/05/10)
-
- Potassium tert-Butoxide-Promoted Acceptorless Dehydrogenation of N-Heterocycles
-
Potassium tert-butoxide-promoted acceptorless dehydrogenation of N-heterocycles was efficiently realized for the generation of N-heteroarenes and hydrogen gas under transition-metal-free conditions. In the presence of KOtBu base, a variety of six- and five-membered N-heterocyclic compounds efficiently underwent acceptorless dehydrogenation to afford the corresponding N-heteroarenes and H2 gas in o-xylene at 140 °C. The present protocol provides a convenient route to aromatic nitrogen-containing compounds and H2 gas. (Figure presented.).
- Liu, Tingting,Wu, Kaikai,Wang, Liandi,Yu, Zhengkun
-
supporting information
p. 3958 - 3964
(2019/08/01)
-
- CONVERSION OF TETRAHYDROQUINOLINE DERIVATIVES TO QUINOLINE USING AZOCOMPOUND
-
The present invention relates to a method of converting tetrahydroquinoline derivatives into quinoline using an azo compound and, more specifically, to a conversion method which is performed in a deuterium chloroform (CDCl_3) or chloroform (CHCl_3) solution including dialkyl azodicarboxylate, which is a method of producing quinoline through a dehydrogenation reaction of 1,2,3,4-tetrahydroquinoline. According to the present invention, a dehydrogenation reaction rate is dependent on the electronic and steric properties of used dialkyl azodicarboxylate; and chloroform shows better results than other substances in solvents screened with diethyl azodicarboxylate. Various types of 1,2,3,4-tetrahydroquinoline undergo the dehydration reaction of the present invention to produce the corresponding quinoline in a yield of at least 90%; and diethyl hydrazo dicarboxylate, which is a reduced form of diethyl azodicarboxylate, is readily separated and recyclable.COPYRIGHT KIPO 2020
- -
-
Paragraph 0041-0042; 0047; 0101-0116
(2020/03/10)
-
- Two-Dimensional Metal-Organic Layers for Electrochemical Acceptorless Dehydrogenation of N-Heterocycles
-
The catalytic acceptorless dehydrogenation (CAD) is an attractive synthetic route to unsaturated compounds because of its high atomic efficiency. Here we report electrochemical acceptorless dehydrogenation of N-heterocycles to obtain quinoline or indole derivatives using metal-organic layer (MOL) catalyst. MOL is the two-dimensional version of metal-organic frameworks (MOF), and it can be constructed on conductive multi-walled carbon nanotubes via facile solvothermal synthesis to overcome the conductivity constraint for MOFs in electrocatalysis. TEMPO-OPO3 2? was incorporated into the system through a ligand exchange with capping formate on the MOL surface to serve as the active catalytic centers. The hybrid catalyst is efficient in the organic conversion and can be readily recycled and reused.
- Yang, Ling,Ma, Fa-Xue,Xu, Fan,Li, Dong,Su, Liangmei,Xu, Hai-Chao,Wang, Cheng
-
supporting information
p. 3557 - 3560
(2019/06/04)
-
- Corrigendum: Organo-Photoredox Catalyzed Oxidative Dehydrogenation of N-Heterocycles (Chemistry - A European Journal, (2017), 23, 57, (14167-14172), 10.1002/chem.201703642)
-
The authors have been alerted to an error that was unfortunately missed at the time of publication. Table was duplicated with Table 4. The correct version of Table 2 is shown below. The authors apologise for any inconvenience caused. Organo-photoredox catalyzed oxidative dehydrogenation of tetrahydroquinolines (THQ).[a,b] (Table presented.) [a] Reaction conditions: 1 (0.5 mmol), rose bengal (1.0 mol %), N,N-dimethylacetamide (2.0 mL), open air atmosphere under visible-light irradiation at room temperature for 24 h. [b] Isolated yields. [c] 0.1 mol % of photoredox catalyst for 28 h.
- Sahoo, Manoj K.,Jaiswal, Garima,Rana, Jagannath,Balaraman, Ekambaram
-
p. 7038 - 7038
(2019/05/17)
-
- Room temperature catalytic dehydrogenation of cyclic amines with the liberation of H2 using water as a solvent
-
Catalytic dehydrogenation of cyclic amines, in particular partially saturated N-heterocycles to N-heterocyclic arenes, with the removal of molecular hydrogen as the sole byproduct in water is reported. This dehydrogenation reaction proceeds smoothly under very mild and benign conditions and operates at room temperature. This distinctive reactivity has been achieved under dual catalytic conditions by merging the visible-light active [Ru(bpy)3]2+ as the photoredox catalyst and a newly synthesized cobalt complex as the proton-reduction catalyst. A detailed mechanistic study (control experiments, electrochemical studies, UV-visible experiments) is presented for the present dual catalysis.
- Sahoo, Manoj K.,Balaraman, Ekambaram
-
supporting information
p. 2119 - 2128
(2019/04/26)
-
- Visible-Light-Mediated Photocatalytic Aerobic Dehydrogenation of N-heterocycles by Surface-Grafted TiO2 and 4-amino-TEMPO
-
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.
-
p. 10694 - 10704
(2019/11/14)
-
- Heterogeneous nickel-catalysed reversible, acceptorless dehydrogenation of N-heterocycles for hydrogen storage
-
Nickel-based nanocatalysts were used in acceptorless, reversible dehydrogenation and hydrogenation reactions of N-heterocycles. Both processes were realized in the same solvent using a single catalyst, without isolation of products and workup, which makes it attractive for hydrogen storage purposes. This concept has been demonstrated in a continuous hydrogenation/dehydrogenation sequence of quinaldine with negligible loss in activity of the nickel catalyst after three hydrogen storage cycles. The scope of acceptorless dehydrogenation has been explored and control experiments suggest that hydrogen liberation is initiated via amine dehydrogenation and supports the direct alkane dehydrogenation from the partially oxidized N-heterocycles.
- Ryabchuk, Pavel,Agapova, Anastasiya,Kreyenschulte, Carsten,Lund, Henrik,Junge, Henrik,Junge, Kathrin,Beller, Matthias
-
supporting information
p. 4969 - 4972
(2019/05/21)
-
- Palladium-Catalyzed Methylation of Aryl, Heteroaryl, and Vinyl Boronate Esters
-
A method for the direct methylation of aryl, heteroaryl, and vinyl boronate esters is reported, involving the reaction of iodomethane with aryl-, heteroaryl-, and vinylboronate esters catalyzed by palladium and PtBu2Me. This transformation occurs with a remarkably broad scope and is suitable for late-stage derivatization of biologically active compounds via the boronate esters. The unique capabilities of this method are demonstrated by combining carbon-boron bond-forming reactions with palladium-catalyzed methylation in a tandem transformation.
- Haydl, Alexander M.,Hartwig, John F.
-
supporting information
p. 1337 - 1341
(2019/02/26)
-
- Ordered Porous Nitrogen-Doped Carbon Matrix with Atomically Dispersed Cobalt Sites as an Efficient Catalyst for Dehydrogenation and Transfer Hydrogenation of N-Heterocycles
-
Single-atom catalysts (SACs) have been explored widely as potential substitutes for homogeneous catalysts. Isolated cobalt single-atom sites were stabilized on an ordered porous nitrogen-doped carbon matrix (ISAS-Co/OPNC). ISAS-Co/OPNC is a highly efficient catalyst for acceptorless dehydrogenation of N-heterocycles to release H2. ISAS-Co/OPNC also exhibits excellent catalytic activity for the reverse transfer hydrogenation (or hydrogenation) of N-heterocycles to store H2, using formic acid or external hydrogen as a hydrogen source. The catalytic performance of ISAS-Co/OPNC in both reactions surpasses previously reported homogeneous and heterogeneous precious-metal catalysts. The reaction mechanisms are systematically investigated using first-principles calculations and it is suggested that the Eley–Rideal mechanism is dominant.
- Han, Yunhu,Wang, Ziyun,Xu, Ruirui,Zhang, Wei,Chen, Wenxing,Zheng, Lirong,Zhang, Jian,Luo, Jun,Wu, Konglin,Zhu, Youqi,Chen, Chen,Peng, Qing,Liu, Qiang,Hu,Wang, Dingsheng,Li, Yadong
-
supporting information
p. 11262 - 11266
(2018/08/28)
-
- Efficient dehydrogenation of 1,2,3,4-tetrahydroquinolines mediated by dialkyl azodicarboxylates
-
Various dialkyl azodicarboxylates were investigated for the dehydrogenation of 1,2,3,4-tetrahydroquinolines to quinolines. The dehydrogenation rates varied according to the electronic and steric nature of the used dialkyl azodicarboxylates. Among solvents screened with diethyl azodicarboxylate, chloroform exhibited superior results to others. A variety of 1,2,3,4-tetrahydroquinolines underwent the present dehydrogenation to produce the corresponding quinolines. Diethyl hydrazodicarboxylate, which is a reduced species of diethyl azodicarboxylate, was easily separated for recycle.
- Bang, Saet Byeol,Kim, Jinho
-
supporting information
p. 1291 - 1298
(2018/04/05)
-
- Oxidation Potential Tunable Organic Molecules and Their Catalytic Application to Aerobic Dehydrogenation of Tetrahydroquinolines
-
In this work, oxidation potential tunable organic molecules, alkyl 2-phenyl hydrazocarboxylates, were disclosed. The exquisite tuning of their oxidation potentials facilitated a catalytic dehydrogenation of 1,2,3,4-tetrahydroquinolines in the presence of Mn(Pc) and O2.
- Jung, Dahyeon,Jang, Seol Heui,Yim, Taeeun,Kim, Jinho
-
supporting information
p. 6436 - 6439
(2018/10/15)
-
- Electrochemical Acceptorless Dehydrogenation of N-Heterocycles Utilizing TEMPO as Organo-Electrocatalyst
-
Catalytic acceptorless dehydrogenation (CAD) has been a basically important organic transformation to ubiquitous unsaturated compounds without the usage of a sacrificial hydrogen acceptor. In this work, we successfully developed the first electrochemical acceptorless dehydrogenation (ECAD) of N-heterocycles using TEMPO as the organo-electrocatalyst. We have achieved the catalytic dehydrogenation of N-heterocycles in an anode and the release of H2 in a cathode using an undivided-cell system. A variety of six-membered and five-membered nitrogen-heteroarenes can be synthesized in good yields in this system. In addition, this protocol can also be used in the application of important molecular synthesis. Our electrochemical strategy provides a mild and metal-free route for (hetero)aromatic compounds synthesis via the CAD strategy.
- Wu, Yong,Yi, Hong,Lei, Aiwen
-
p. 1192 - 1196
(2018/02/14)
-
- Actinide-Based Porphyrinic MOF as a Dehydrogenation Catalyst
-
Uranyl–organic frameworks (UOFs) have recently been the object of many research endeavors due to the unique coordination mode of uranyl ions and their attractive physicochemical properties. Here, a new (3,4)-connected UOF (U-IHEP-4) assembled from uranyl and porphyrin ligand tetrakis(4-carboxyphenyl)porphyrin (H4TCPP) is reported, which represents the first case of actinide porphyrinic MOFs. Adsorption experiments in DMF solution demonstrated that U-IHEP-4 selectively adsorbs positively charged dyes, which is in line with its negatively charged framework and large pore volume ratio (90 %). Remarkably, U-IHEP-4 exhibited high catalytic activity for the dehydrogenation of N-heterocycles to synthesize the corresponding aromatic heterocycles and it can be used as an efficient heterogeneous catalyst.
- Hu, Kong-Qiu,Huang, Zhi-Wei,Zhang, Zhi-Hui,Mei, Lei,Qian, Bing-Bing,Yu, Ji-Pan,Chai, Zhi-Fang,Shi, Wei-Qun
-
supporting information
p. 16766 - 16769
(2018/10/31)
-
- Aerobic oxidative dehydrogenation of N-heterocycles catalyzed by cobalt porphyrin
-
An efficient catalytic procedure has been developed for the aerobic oxidative dehydrogenation of N-heterocycles by cobalt porphyrin in the absence of any additives. The catalytic system could tolerate various 1,2,3,4-tetrahydroquinoline derivatives and some other N-heterocycles. The corresponding N-heteroaromatics could be obtained in 59–86% yields. The mechanism investigation suggested that the aerobic oxidative dehydrogenation might proceed with imine intermediate through radical paths.
- Zhou, Weiyou,Chen, Dongwei,Sun, Fu'an,Qian, Junfeng,He, Mingyang,Chen, Qun
-
supporting information
p. 949 - 953
(2018/02/09)
-
- Osmium Catalysts for Acceptorless and Base-Free Dehydrogenation of Alcohols and Amines: Unusual Coordination Modes of a BPI Anion
-
A novel type of catalyst precursors for the dehydrogenation of hydrogen carriers based on organic liquids has been discovered. Complexes OsH6(PiPr3)2 (1) and OsH(OH)(CO)(PiPr3)2 (2) react with 1,3-bis(6′-methyl-2′-pyridylimino)isoindoline (HBMePI) to give OsH3{κ2-Npy,Nimine-(BMePI)}(PiPr3)2 (3) and OsH{κ2-Npy,Nimine-(BMePI)}(CO)(PiPr3)2 (4). The unprecedented κ2-Npy,Nimine coordination mode of BMePI is thermodynamically preferred with Os(IV) and Os(II) metal fragments and allows for preparation of BMePI-based dinuclear metal cations. Treatment of OsH2Cl2(PiPr3)2 (5) with 0.5 equiv of HBMePI in the presence of KOtBu affords the chloride salt of the bis(osmium(IV)) dinuclear cation [{OsH3(PiPr3)2}2{μ-(κ2-Npy,Nimine)2-BMePI}]+ (6). Related homoleptic bis(osmium(II)) complexes have been also synthesized. Complex 4 reacts with the bis(solvento) [OsH(CO){κ1-O-[OCMe2]2}(PiPr3)2]BF4 to give [{OsH(CO)(PiPr3)2}2{μ-(κ2-Npy,Nimine)2-BMePI}]BF4 (7), whereas the addition of 0.5 equiv of HBMePI to {OsCl(η6-C6H6)}2(μ-Cl)2 (8) affords [{OsCl(η6-C6H6)}2{μ-(κ2-Npy,Nimine)2-BMePI}]Cl (9). The reactions of 4 with 8 and {OsCl(η6-p-cymene)}2(μ-Cl)2 (10) lead to the heteroleptic cations [(PiPr3)2(CO)HOs{μ-(κ2-Npy,Nimine)2-BMePI}OsCl(η6-arene)]+ (arene = C6H6 (11), p-cymene (12)). The electronic structrure and electrochemical properties of the dinuclear complexes were also studied. Complexes 3 and 4 are efficient catalyst precursors for the acceptorless and base-free dehydrogenation of secondary and primary alcohols and cyclic and lineal amines. The primary alcohols afford aldehydes. The amount of H2 released per gram of heterocycle depends upon the presence of a methyl group adjacent to the nitrogen atom, the position of the nitrogen atom in the heterocycle, and the size of the heterocycle.
- Buil, María L.,Esteruelas, Miguel A.,Gay, M. Pilar,Gómez-Gallego, Mar,Nicasio, Antonio I.,O?ate, Enrique,Santiago, Alicia,Sierra, Miguel A.
-
p. 603 - 617
(2018/03/08)
-
- Vanadium-Catalyzed Dehydrogenation of N-Heterocycles in Water
-
In this paper, the dehydrogenation of tetrahydroquinolines using oxovanadium(V) catalysts under mild conditions in water and oxygen atmosphere is described. This catalytic technology was successfully applied to a range of other structurally related N-heterocycles, and a reaction mechanism is proposed.
- Zumbr?gel, Nadine,Sako, Makoto,Takizawa, Shinobu,Sasai, Hiroaki,Gr?ger, Harald
-
supporting information
p. 4723 - 4727
(2018/08/23)
-
- Pd-Catalyzed Alkylation of (Iso)quinolines and Arenes: 2-Acylpyridine Compounds as Alkylation Reagents
-
The first Pd-catalyzed alkylation of (iso)quinolines and arenes is reported. The readily available and bench-stable 2-acylpyridine compounds were used as an alkylation reagent to form the structurally versatile alkylated (iso)quinolines and arenes. The method affords a convenient pathway for the introduction of alkyl groups into organic molecules.
- Wu, Qingsong,Han, Shuaijun,Ren, Xiaoxiao,Lu, Hongtao,Li, Jingya,Zou, Dapeng,Wu, Yangjie,Wu, Yusheng
-
supporting information
p. 6345 - 6348
(2018/10/20)
-
- Nickel-catalyzed C-O bond reduction of aryl and benzyl 2-pyridyl ethers
-
The reduction of aryl and benzyl 2-pyridyl ethers with sodium isopropoxide was carried out via nickel-catalyzed C-OPy bond cleavage, giving reductive products in reasonable to excellent yields. This method allowed the 2-pyridyloxy group to be directly rem
- Li, Jing,Wang, Zhong-Xia
-
supporting information
p. 2138 - 2141
(2018/03/06)
-
- High efficiency microwave-assisted synthesis of quinoline from acrolein diethyl acetal and aniline utilizing Ni/Beta catalyst
-
A facile and solvent-free microwave-assisted approach to quinoline was developed by utilizing both acrolein diethyl acetal and aniline as reagents, firstly employing Ni/Beta zeolite as mild, ecofriendly and low-cost solid catalyst. As high as 83% yield of quinoline was quickly achieved at a short microwave time. The results indicated that the effect of Ni on Beta zeolite not only significantly promoted conversion of acrolein diethyl acetal to effective intermediate but also dramatically accelerated dehydrogenation rate of tetrahydroquinoline/dihydroquinoline to quinoline.
- Li, An,Yang, Zan,Yang, Tao,Luo, Cai-Wu,Chao, Zi-Sheng,Zhou, Cong-Shan
-
-
- Visible-Light Photocatalyzed Deoxygenation of N-Heterocyclic N-Oxides
-
A scalable and operationally simple method is described that allows for the chemoselective deoxygenation of a wide range of N-heterocyclic N-oxides (a total of 36 examples). This visible-light-induced protocol features the use of only commercially available reagents, room-temperature conditions, and unprecedented chemoselective removal of the oxygen atom in a quinoline N-oxide in the presence of a pyridine N-oxide in the same molecule through the judicious selection of a photocatalyst.
- Kim, Kyu Dong,Lee, Jun Hee
-
supporting information
p. 7712 - 7716
(2019/01/03)
-
- Method for compounding quinoline compound in manner of oxidative dehydrogenation of tetrahydroquinoline compound through visible light catalysis
-
The invention discloses a method for compounding a quinoline compound in the manner of oxidative dehydrogenation of a tetrahydroquinoline compound through visible light catalysis. The method comprises the following steps: utilizing oxygen to replace peroxide as an oxidizing agent; taking polysubstituted BODIPY organic compound as a photocatalyst; catalyzing the oxidative dehydrogenation of 1,2,3,4-tetrahydroquinoline compound and compounding the quinoline compound. Compared with the present compounding method, the method has the advantages of mild reaction condition, metal-free photocatalyst used in the reaction, less dosage of the catalyst, high catalytic efficiency, stabilization, high efficiency, simple operation, environmental protection, high conversion rate of products and excellent selectivity.
- -
-
Paragraph 0018; 0019; 0020-0023; 0030-0050; 0091-0094
(2017/10/07)
-
- Preparation method of quinoline derivative
-
The invention provides a preparation method of a quinoline derivative. The method includes the steps of: in the presence of an oxidizing agent, adding a catalyst, then adding aniline or aromatic amine with different substituents, at the same time adding alcohol for reaction so as to prepare the quinoline derivative by one step. Specifically, the catalyst comprises a metal catalyst, an assistant catalyst I and an assistant catalyst II; the metal catalyst is a transition metal catalyst; the assistant catalyst I is an alkaline nitrogen-containing ligand; and the assistant catalyst II is an acidic compound. The quinoline derivative prepared by the method provided by the invention has stable performance and high purity. And the preparation method of the quinoline derivative can prepare quinoline, 2-methylquinoline, 8-hydroxyquinoline quinoline and other derivatives by one-step reaction, and the preparation method is simple and practicable. The preparation process does not produce new "three wastes", is environment-friendly, and provides a green and environment-friendly synthesis method. The preparation method has the characteristics of few raw material variety, little reaction equipment, few preparation step and low cost, and is more suitable for industrial production.
- -
-
Paragraph 0105; 0106
(2017/06/02)
-
- Assembly of Diversely Substituted Quinolines via Aerobic Oxidative Aromatization from Simple Alcohols and Anilines
-
An aerobic oxidative aromatization of simple aliphatic alcohols and anilines under the Pd(OAc)2/2,4,6-Collidine/Br?nsted acid catalytic system has been established, providing a direct approach for the preparation of diverse substituted quinoline derivatives in high yields with wide functional group tolerance. Practically, the protocol can be easily scaled up to gram-scale and was utilized in the concise formal synthesis of a promising herbicide candidate.
- Li, Jixing,Zhang, Jinlong,Yang, Huameng,Jiang, Gaoxi
-
supporting information
p. 3284 - 3290
(2017/03/23)
-
- Acceptorless dehydrogenation of N-heterocycles by supported Pt catalysts
-
Pt metal nanoparticles loaded on various supports and carbon-supported various metal catalysts are tested for dehydrogenation of 6-methyl-1,2,3,4- tetrahydroquinoline to 6-methyl-quinoline under oxidant-free conditions. In the 20 types of the catalysts screened, carbon-supported Pt catalyst (Pt/C) shows the highest activity. Pt/C is reusable after the reaction and is effective for dehydrogenation of various N- heterocycles (tetrahydroquinolines and indoline). Pt/C is also effective for hydrogenation of quinoline under 3 bar H2. The results demonstrate that this catalytic method may be useful for an organic hidride–based hydrogen storage system.
- Moromi, Sondomoyee K.,Siddiki,Kon, Kenichi,Toyao, Takashi,Shimizu, Ken-ichi
-
p. 507 - 511
(2016/12/09)
-
- Acceptorless Dehydrogenation of N-Heterocycles by Merging Visible-Light Photoredox Catalysis and Cobalt Catalysis
-
Herein, the first acceptorless dehydrogenation of tetrahydroquinolines (THQs), indolines, and other related N-heterocycles, by merging visible-light photoredox catalysis and cobalt catalysis at ambient temperature, is described. The potential applications to organic transformations and hydrogen-storage materials are demonstrated. Primary mechanistic investigations indicate that the catalytic cycle occurs predominantly by an oxidative quenching pathway.
- He, Ke-Han,Tan, Fang-Fang,Zhou, Chao-Zheng,Zhou, Gui-Jiang,Yang, Xiao-Long,Li, Yang
-
supporting information
p. 3080 - 3084
(2017/03/14)
-
- Method for preparing quinoline derivative by catalyzing oxidative dehydrogenation of nitrogen-containing heterocyclic ring through carbon nitride material
-
The invention belongs to the field of chemical synthesis, and particularly relates to a method for preparing a quinoline derivative by catalyzing oxidative dehydrogenation of a nitrogen-containing heterocyclic ring through a carbon nitride material. The carbon nitride material is prepared by using a nitrogen-containing organic macrocyclic compound as a precursor and calcining in an inert atmosphere. During a reaction, oxygen or air is used as an oxidant, and in the presence or absence of a solvent, the reaction is performed at 50-120 DEG C and the carbon nitrogen material can convert the nitrogen-containing heterocyclic ring into the corresponding quinoline derivative. According to the invention, no metal is introduced into a reaction system, and the method is easy to amplify; after being recycled for at least 9 times, a catalyst still maintain good selectivity and activity; therefore, the method has a significant practical prospect during industrial production.
- -
-
Paragraph 0014; 0015
(2017/08/29)
-
- Dehydrogenation of Nitrogen Heterocycles Using Graphene Oxide as a Versatile Metal-Free Catalyst under Air
-
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
-
supporting information
p. 2358 - 2363
(2017/07/22)
-
- Organo-Photoredox Catalyzed Oxidative Dehydrogenation of N-Heterocycles
-
We report here for the first time the catalytic oxidative dehydrogenation of N-heterocycles by a visible-light organo-photoredox catalyst with low catalyst loading (0.1–1 mol %). The reaction proceeds efficiently under base- and additive-free conditions with ambient air at room temperature. The utility of this benign approach is demonstrated by the synthesis of various pharmaceutically relevant N-heteroarenes such as quinoline, quinoxaline, quinazoline, acridine, and indole.
- Sahoo, Manoj K.,Jaiswal, Garima,Rana, Jagannath,Balaraman, Ekambaram
-
supporting information
p. 14167 - 14172
(2017/10/16)
-
- Non-redox metal ions promoted oxidative dehydrogenation of saturated C[sbnd]C bond by simple Pd(OAc)2 catalyst
-
Adding non-redox metal ions to simple Pd(OAc)2 catalyst can remarkably promote oxidative dehydrogenation of saturated C[sbnd]C bond, and the activity improvement is Lewis acidity strength dependent. Through UV–vis and NMR characterizations of the catalyst, it was proposed that in-situ generated heteronuclear Pd(II)/Zn(II) dimer is the key active species for dehydrogenation.
- Lou, Chenlin,Qin, Shuhao,Zhang, Sicheng,Lv, Zhanao,Senan, Ahmed M.,Chen, Zhuqi,Yin, Guochuan
-
-