- Symbiotic Transition-Metal and Organocatalysis for Catalytic Ambient Amine Oxidation and Alkene Reduction Reactions
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A new oxidation reaction based on two simple catalysts, namely, alloxan and a CuI salt, is highly effective for the aerobic oxidation and oxidative cross-coupling of amines. The reaction is operationally simple, reaction atmospheres enriched in dioxygen are obviated, and neither catalyst component requires prior synthesis. Mechanistic investigations have been performed and point towards a complex reaction manifold with evidence that supports a catalytic cycle that does not proceed through a quinone-imine step. Additionally, this dual catalyst system is efficient to effect diimide-mediated hydrogenation reactions of alkenes and alkynes, a transformation that has not been reported previously in the context of quinone catalyst systems.
- Murray, Alexander T.,King, Rose,Donnelly, Joseph V. G.,Dowley, Myles J. H.,Tuna, Floriana,Sells, Daniel,John, Matthew P.,Carbery, David R.
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- Investigations on the crystal plane effect of ceria on gold catalysis in the oxidative dehydrogenation of alcohols and amines in the liquid phase
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Gold nanoparticles supported on ceria{110} crystal planes were more reactive than on ceria{111} and {100} in the oxidative dehydrogenation of alcohols. Kinetic analysis and a Hammett plot suggest that hydride transfer is involved, and the cationic gold is catalytically active.
- Wang, Min,Wang, Feng,Ma, Jiping,Li, Mingrun,Zhang, Zhe,Wang, Yehong,Zhang, Xiaochen,Xu, Jie
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- Visible-light-induced photoredox catalysis with a tetracerium-containing silicotungstate
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The development of visible-light-induced photocatalysts for chemoselective functional group transformations has received considerable attention. Polyoxometalates (POMs) are potential materials for efficient photocatalysts because their properties can be p
- Suzuki, Kosuke,Tang, Fei,Kikukawa, Yuji,Yamaguchi, Kazuya,Mizuno, Noritaka
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- Oxygen-vacancy-mediated exciton dissociation in biobr for boosting charge-carrier-involved molecular oxygen activation
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Excitonic effects mediated by Coulomb interactions between photogenerated electrons and holes play crucial roles in photoinduced processes of semiconductors. In terms of photocatalysis, however, efforts have seldom been devoted to the relevant aspects. Fo
- Wang, Hui,Yong, Dingyu,Chen, Shichuan,Jiang, Shenlong,Zhang, Xiaodong,Shao, Wei,Zhang, Qun,Yan, Wensheng,Pan, Bicai,Xie, Yi
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- Exciton-Mediated Energy Transfer in Heterojunction Enables Infrared Light Photocatalysis
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Although a few semiconductors can directly absorb infrared light, their intrinsic properties like improper band-edge position and strong electron–hole interaction restrict further photocatalytic applications. Herein, we propose an exciton-mediated energy
- Jin, Sen,Li, Yuanjin,Liu, Wenxiu,Wang, Hui,Wang, Shuhui,Xie, Yi,Xu, Xiaoliang,Zhang, Xiaodong,Zhao, Zhi
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- Highly efficient CeO2-MoO3/SiO2 catalyst for solvent-free oxidative coupling of benzylamines into N-benzylbenzaldimines with O2 as the oxidant
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The development of noble-metal-free catalysts is currently a topic of paramount research investigation in the chemical industry. In this work, a promising CeO2- MoO3/SiO2 catalyst was synthesized for the oxidation of a wide variety of benzylamines with O2 as the oxidant under solvent-free conditions. For comparison, the efficiency of CeO2 and CeO2-MoO3 catalysts were also studied for the oxidation of benzylamine under identical conditions. The physicochemical properties of the catalysts were thoroughly analysed using X-ray diffraction, Raman spectroscopy, Barrett-Joyner-Halenda pore size distribution, Brunauer-Emmet-Teller (BET) surface area, Fouriertransform infrared spectroscopy, ammonia-temperature programmed desorption (NH3-TPD), and X-ray photoelectron spectroscopy techniques. Characterization studies revealed that the CeO2-MoO3/SiO2 catalyst shows favourable structural, textural and acidic properties, which are due to strong interaction between the Ce-Mo mixed oxide and the SiO2. In particular, the CeO2-MoO3/SiO2 sample exhibits smaller crystallite size and highest BET surface area compared with the CeO2-MoO3 and bare CeO2. Raman analysis revealed that the CeO2-MoO3/SiO2 sample exhibits greater number of oxygen vacancy defects. The NH3-TPD studies indicated that the CeO2-MoO3/SiO2 sample has large amount of acidic sites. Owing to the beneficial properties, the CeO2-MoO3/SiO2 sample exhibited an outstanding catalytic performance for the aerobic oxidation of various benzylamines. The achieved benzylamine conversions are *16, 65 and 98 %, respectively, for CeO2, CeO2-MoO3 and CeO2-MoO3/SiO2 samples. Despite the nature of the catalyst used and the reaction conditions employed, almost *100 % selectivity for the dibenzylimine product was found in the present study. Remarkably, the CeO2-MoO3/SiO2 catalyst can be repeatedly used up to 5 cycles without any considerable variation in the benzylamine conversion and imine product selectivity. Graphical Abstract The CeO2-MoO3/SiO2 catalyst showed an outstanding efficiency in the oxidation of benzylamine, which is attributed to abundant acidic sites, large number of oxygen vacancies, and superior BET surface area.
- Rao, Bolla Govinda,Sudarsanam, Putla,Rangaswamy,Reddy, Benjaram M.
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- Novel molybdenum–cerium based heterogeneous catalysts for efficient oxidative coupling of benzylamines under eco-friendly conditions
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Abstract: This work demonstrates that MoOx/CeO2–ZrO2 solid acid acts as a promising catalyst in the solvent-free oxidative-coupling of benzylamine into dibenzylimine with O2 as the oxidant. The benzylamine conversions were found to be ~27, 51, 74, and 99?% for CeO2, CeO2–ZrO2, MoOx/CeO2, and MoOx/CeO2–ZrO2 catalysts, respectively. The MoOx/CeO2–ZrO2 catalyst also efficiently converts various substituted- and secondary-benzylamines under solvent-free conditions with O2 resulting in moderate to excellent yields. Remarkably, a high selectivity of ~99.6–99.9?% towards the dibenzylimine product was found for all reaction conditions. The outstanding performance of MoOx/CeO2–ZrO2 catalyst was attributed to high specific surface area, improved structural defects, and superior acid properties. Graphical Abstract: [Figure not available: see fulltext.] The MoOx/CeO2–ZrO2 catalyst show an outstanding performance in the oxidation of benzylamine and its derivatives, which is attributed to abundant acidic sites, large number of oxygen vacancies, and superior BET surface area.
- Rangaswamy, Agolu,Sudarsanam, Putla,Rao, Bolla Govinda,Reddy, Benjaram M.
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- Aerobic Photooxidative Synthesis of Secondary Aldimines from Benzylamines by Using Methylene Blue
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We have developed a concise oxidative coupling of primary benzylamines to yield secondary aldimines catalyzed by methylene blue by using molecular oxygen as the oxidant in the presence of visible-light irradiation from fluorescent lamps.
- Okada, Akifumi,Yuasa, Hiroki,Fujiya, Akitoshi,Tada, Norihiro,Miura, Tsuyoshi,Itoh, Akichika
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Read Online
- Catalytic dehydrogenation of amines to imines and the in-situ reduction of sulfoxides into sulfides
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The catalytic acceptorless dehydrogenation of primary amines into imines and H2 represents one of the most important organic transformations, and the in-situ utilization of the generated H2 for chemical reduction reactions has never
- Li, Bo,Liu, Bing,Liu, Xixi,Wang, Wei,Wang, Yanxin,Xiang, Nian,Zhang, Zehui
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- Unveiling Charge Dynamics in Acetylene-Bridged Donor-π-Acceptor Covalent Triazine Framework for Enhanced Photoredox Catalysis
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Covalent triazine frameworks (CTFs) with donor-acceptor motifs have been identified as prospective semiconducting materials for photocatalysis. Though donor-acceptor motifs can favor forward intramolecular charge separation, some cases still suffer from b
- Lan, Xingwang,Liu, Xiaopeng,Zhang, Yize,Li, Qing,Wang, Juan,Zhang, Qianfan,Bai, Guoyi
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p. 7429 - 7441
(2021/06/30)
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- The effect of halogen on arylsulfonylated phenothiazines for solid-sate luminescence and photocatalytic performance
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Halogen atom effect on organic luminescence materials incorporating arylsulfonylated phenothiazine as the central unit was investigated in both solid state and organic solution. New organic solids with very weak C-halogen?π interactions are constructed, i
- Liu, Caiyan,Shen, Yongli,Ye, Kaiqi,Yuan, Kedong,Zhao, Yunfeng
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p. 604 - 610
(2020/07/23)
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- Visible-Light-Driven Selective Oxidative Coupling of Amines to Imines by Bismuth-Rich Bismuth Oxybromide in Water
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Photocatalytic selective oxidative coupling of amines is a promising method for imine synthesis. Bismuth-rich bismuth oxybromide photocatalysts have been found to exhibit improved conversion and selectivity for the visible-light-driven selective oxidative
- Zhao, Wei,Yang, Chunxia,Zhang, Xu,Deng, Yu,Han, Chunqiu,Ma, Zhaoyu,Wang, Li,Ye, Liqun
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p. 116 - 120
(2019/12/27)
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- Easy Ruthenium-Catalysed Oxidation of Primary Amines to Nitriles under Oxidant-Free Conditions
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A dehydrogenation of primary amine to give the corresponding nitrile under oxidant- and base-free conditions catalysed by simple [Ru(p-cym)Cl2]2 with no extra ligand is reported. The system is highly selective for alkyl amines, whereas benzylamine derivatives gave the nitrile product together with the imine in a ratio ranging from 14:1 to 4:1 depending on the substrate. Preliminary mechanistic investigations have been performed to identify the key factors that govern the selectivity.
- Achard, Thierry,Egly, Julien,Sigrist, Michel,Maisse-Fran?ois, Aline,Bellemin-Laponnaz, Stéphane
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supporting information
p. 13271 - 13274
(2019/10/21)
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- Table salt as a catalyst for the oxidation of aromatic alcohols and amines to acids and imines in aqueous medium: Effectively carrying out oxidation reactions in sea water
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A simple, efficient, sustainable and economical method for the oxidation of alcohols and amines has been developed based on chloride, a sea abundant anionic catalyst for the practical synthesis of a wide range of carboxylic acids, ketones and imines. Oxidation of aromatic alcohols was carried out using NaCl (20 mol%) as the catalyst, NaOH (50 mol%) and aq. TBHP (4 equiv.) as the oxidant in 55-92% isolated yields. Oxidation of aromatic amines to imines was achieved by using only 20 mol% of NaCl and aq. TBHP (4 equiv.) in 32-93% isolated yields. The chlorine species formed during the reaction as the active oxidation catalyst has been identified as ClO2- for alcohols and ClO-/ClO2- for amines by control experiments. This method is mostly free from chromatographic purification, which makes it suitable for large-scale synthesis. We have scaled up to 30 gram scale the synthesis of carboxylic acids and imines in good yields and have also carried out efficiently this new method using filtered sea water as the solvent and catalyst.
- Hazra, Susanta,Kushawaha, Ajay Kishor,Yadav, Deepak,Dolui, Pritam,Deb, Mayukh,Elias, Anil J.
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supporting information
p. 1929 - 1934
(2019/04/29)
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- Selectivity-tunable amine aerobic oxidation catalysed by metal-free N,O-doped carbons
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Herein, we present a series of N,O-doped mesoporous carbons obtained at different pyrolysis temperatures as the first metal-free catalysts which successfully switch between imine and nitrile products for amine oxidation. Systematic characterization studies and control experiments revealed that the C-O group on the surface could function as a catalytically active site for nitrile synthesis and the N-doping environment was essential.
- Li, Yingguang,Shang, Sensen,Wang, Lianyue,Lv, Ying,Niu, Jingyang,Gao, Shuang
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supporting information
p. 12251 - 12254
(2019/10/21)
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- Seaweed-like 2D-2D Architecture of MoS2/rGO Composites for Enhanced Selective Aerobic Oxidative Coupling of Amines
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To provide a solution for pursuing high redox reactivity beyond the compromise between the numbers of sulfur vacancies and electron transfer ability, 2D-2D architecture of MoS2/rGO composite was fabricated with 2D graphene-like transition metal
- Wang, Mingming,Wu, Haihong,Shen, Chaoren,Luo, Shuping,Wang, Dan,He, Lin,Xia, Chungu,Zhu, Gangli
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p. 1935 - 1942
(2019/03/21)
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- Method for synthesizing imide type compound by carrying out visible light catalytic oxidation on amine type compound
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The invention discloses a method for synthesizing an imide type compound by carrying out visible light catalytic oxidation on an amine type compound. The method takes tetrahydroxymethyl tetra(1,4-dithiin)tetraaza-cobalt porphyrin as a catalyst and molecul
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Paragraph 0034-0040; 0065-0071
(2019/08/30)
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- Method for preparing imine compounds
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The invention discloses a method for preparing an imine compounds. According to the method, under the absence of an oxidizing agent, a copper catalyst is utilized to for catalyzingse an amine compounds to prepare imine in a coupling manner. According to t
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Paragraph 0033; 0034; 0035
(2019/01/08)
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- Direct synthesis of nitriles by Cu/DMEDA/TEMPO-catalyzed aerobic oxidation of primary amines with air
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By screening the copper catalysts, ligands, and the reaction conditions, a simple CuCl/DMEDA/TEMPO catalyst system readily available from commercial sources is developed for a direct and selective synthesis of the useful nitriles by an aerobic oxidation reaction of primary amines using air as an advantageous oxidant under mild conditions.
- Ma, Xian-Tao,Xu, Hao,Xiao, Ying-Lin,Su, Chen-Liang,Liu, Jian-Ping,Xu, Qing
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p. 1336 - 1339
(2017/06/21)
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- Co-N-C supported on SiO2: A facile, efficient catalyst for aerobic oxidation of amines to imines
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We developed a novel, facile preparation method of Co-N-C/SiO2, which was the pyrolysis of silicone gel containing metal ion and triethanolamine (TEA) prepared by sol-gel process. N2 adsorption-desorption characterization displayed the sample had high specific surface area and pore volume (220.9 m2 g-1, 0.67 mL g-1). The active Co appeared to be small particles with size of about 5 nm and was well dispersed on SiO2. And the highly dispersed cobalt and nitrogen-doped carbon in Co-N-C/SiO2 served as active phase for the oxidation of amines to imines, thus Co-N-C/SiO2 could efficiently catalyze the oxidation of amines to imines in solvent-free, air atmospheric conditions, avoiding the use of large excesses of additives, specialized oxidant and solvent.
- Zhang, Chenghui,Zhao, Pengshan,Zhang, Zongliang,Zhang, Jingwei,Yang, Ping,Gao, Peng,Gao, Jun,Liu, Di
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p. 47366 - 47372
(2017/10/19)
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- Active and Recyclable Catalytic Synthesis of Indoles by Reductive Cyclization of 2-(2-Nitroaryl)acetonitriles in the Presence of Co-Rh Heterobimetallic Nanoparticles with Atmospheric Hydrogen under Mild Conditions
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A cobalt-rhodium heterobimetallic nanoparticle-catalyzed reductive cyclization of 2-(2-nitroaryl)acetonitriles to indoles has been achieved. The tandem reaction proceeds without any additives under the mild conditions (1 atm H2 and 25 °C). This procedure could be scaled up to the gram scale. The catalytic system is significantly stable under these reaction conditions and could be reused more than ten times without loss of catalytic activity.
- Choi, Isaac,Chung, Hyunho,Park, Jang Won,Chung, Young Keun
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p. 5508 - 5511
(2016/11/17)
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- Monocyclic β-lactam and unexpected oxazinone formation: synthesis, crystal structure, docking studies and antibacterial evaluation
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Novel monocyclic β-lactam derivatives bearing aryl, phenyl and heterocyclic rings were synthesized as possible antibacterial agents. Cyclization of imines (3h, 3t) with phenylacetic acid in the presence of phosphoryl chloride and triethyl amine did not afford the expected β-lactams. Instead, highly substituted 1,3-oxazin-4-ones (4h, 4t) were isolated as the only product and confirmed by single crystal X-ray analysis of 4t. The results of antibacterial activity showed that compound 4l exhibited considerable antibacterial activity with MIC and MBC values of 62.5 μg/mL against Klebsiella pneumoniae. Cytotoxicity assay on Chinese Hamster Ovary (CHO) cell line revealed non-cytotoxic behavior of compounds 4d, 4h, 4k and 4l up to 200 μg/mL conc. Molecular docking was performed for compound 4l with penicillin binding protein-5 to identify the nature of interactions. The results of both in silico and in vitro evaluation provide the basis for compound 4l to be carried as a potential lead molecule in the drug discovery pipeline against bacterial infections.
- Aneja, Babita,Irfan, Mohammad,Hassan, Md. Imtaiyaz,Prakash, Amresh,Yadava, Umesh,Daniliuc, Constantin G.,Zafaryab, Md.,Rizvi, M. Moshahid A.,Azam, Amir,Abid, Mohammad
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p. 834 - 852
(2016/07/07)
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- C70 as a Photocatalyst for Oxidation of Secondary Benzylamines to Imines
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Photosensitive C70 was used for the catalytic oxidation of benzylamines to the corresponding imines. The advantages of using C70 compared to C60 or other commonly used photosensitizers such as tetraphenylporphyrin (TPP) ar
- Kumar, Rakesh,Glei?ner, Eva H.,Tiu, Elisha Gabrielle V.,Yamakoshi, Yoko
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supporting information
p. 184 - 187
(2016/02/05)
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- A Solvent-Free Process for Synthesis of Imines by Iron-Catalyzed Oxidative Self- or Cross-Condensation of Primary Amines Using Molecular Oxygen as Sole Oxidant
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Abstract: The synthesis of imines by oxidative self- or cross-condensation of primary amines has been achieved using iron(II) bromide as the catalyst. The protocol is ligand-free, additive-free, solvent-free, and high-yielding and utilizes renewable oxygen as sole oxidant. The reaction tolerated a wide range of functionalities. Graphical Abstract: [Figure not available: see fulltext.]
- Gopalaiah, Kovuru,Saini, Anupama
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p. 1648 - 1654
(2016/08/30)
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- Magnetically separable CuFe2O4/reduced graphene oxide nanocomposites: As a highly active catalyst for solvent free oxidative coupling of amines to imines
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In this report, a very simple and straightforward one step coprecipitation method was used for decorating CuFe2O4 nanoparticles (NPs) over graphene sheets. The as synthesized CuFe2O4/RGO nanocomposites (CFRNCs)
- Dhanda, Ritu,Kidwai, Mazaahir
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p. 53430 - 53437
(2016/06/14)
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- Aerobic oxidation of amines to imines catalyzed by a ruthenium complex under solvent-free conditions
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A ruthenium complex [Et3NH]2[Ru(dipic)Cl3] showed high efficiency in the homo-coupling of primary amines and cross-coupling of benzylamine with anilines and aliphatic amines to the corresponding imines under air and solvent-free conditions. This protocol is an atom-economical green process and tolerates various substrates bearing both electron-donating and electron-withdrawing substituents.
- Zhang, Yuecheng,Lu, Fei,Huang, Rong,Zhang, Hongyu,Zhao, Jiquan
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supporting information
p. 10 - 13
(2016/04/26)
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- Simple Copper Catalysts for the Aerobic Oxidation of Amines: Selectivity Control by the Counterion
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We describe the use of simple copper-salt catalysts in the selective aerobic oxidation of amines to nitriles or imines. These catalysts are marked by their exceptional efficiency, operate at ambient temperature and pressure, and allow the oxidation of amines without expensive ligands or additives. This study highlights the significant role counterions can play in controlling selectivity in catalytic aerobic oxidations.
- Xu, Boran,Hartigan, Elizabeth M.,Feula, Giancarlo,Huang, Zheng,Lumb, Jean-Philip,Arndtsen, Bruce A.
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supporting information
p. 15802 - 15806
(2016/12/16)
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- Selective oxidation of amines to aldehydes or imines using laccase-mediated bio-oxidation
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An efficient and practical chemo-enzymatic aerobic oxidation in water of benzylamines to obtain aldehydes or imines is described. Laccase from Trametes versicolor was chosen as biocatalyst, and TEMPO (radical 2,2,6,6-tetramethylpiperidine 1-oxyl) as mediator. A study on the pH dependence of the aqueous medium allowed us to realise a fine tuning on product selectivity. Under our optimized reaction conditions, the bio-oxidation of a series of primary, secondary and cyclic amines has been achieved.
- Galletti, Paola,Funiciello, Federica,Soldati, Roberto,Giacomini, Daria
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p. 1840 - 1848
(2015/06/02)
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- Catalytic Amine Oxidation under Ambient Aerobic Conditions: Mimicry of Monoamine Oxidase B
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The flavoenzyme monoamine oxidase (MAO) regulates mammalian behavioral patterns by modulating neurotransmitters such as adrenaline and serotonin. The mechanistic basis which underpins this enzyme is far from agreed upon. Reported herein is that the combination of a synthetic flavin and alloxan generates a catalyst system which facilitates biomimetic amine oxidation. Mechanistic and electron paramagnetic (EPR) spectroscopic data supports the conclusion that the reaction proceeds through a radical manifold. This data provides the first example of a biorelevant synthetic model for monoamine oxidase B activity.
- Murray, Alexander T.,Dowley, Myles J. H.,Pradaux-Caggiano, Fabienne,Baldansuren, Amgalanbaatar,Fielding, Alistair J.,Tuna, Floriana,Hendon, Christopher H.,Walsh, Aron,Lloyd-Jones, Guy C.,John, Matthew P.,Carbery, David R.
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supporting information
p. 8997 - 9000
(2015/08/03)
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- Factors influencing the regioselectivity of the oxidation of asymmetric secondary amines with singlet oxygen
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Aerobic amine oxidation is an attractive and elegant process for the α functionalization of amines. However, there are still several mechanistic uncertainties, particularly the factors governing the regioselectivity of the oxidation of asymmetric secondary amines and the oxidation rates of mixed primary amines. Herein, it is reported that singlet-oxygen-mediated oxidation of 1° and 2° amines is sensitive to the strength of the α-C-H bond and steric factors. Estimation of the relative bond dissociation energy by natural bond order analysis or by means of one-bond C-H coupling constants allowed the regioselectivity of secondary amine oxidations to be explained and predicted. In addition, the findings were utilized to synthesize highly regioselective substrates and perform selective amine cross-couplings to produce imines.
- Ushakov, Dmitry B.,Plutschack, Matthew B.,Gilmore, Kerry,Seeberger, Peter H.
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supporting information
p. 6528 - 6534
(2015/04/22)
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- The Cu(OTf)2 catalysed microwave assisted synthesis of a new scaffold, 7-aryl-7,8-dihydropyrido[4,3-c]pyridazin-5(6H )-one
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The synthesis of novel 7-aryl-7,8-dihydropyrido[4,3-c]pyridazin-5(6 H)-ones is described including a one-step Mannich-type reaction followed by intramolecular ring closure of ethyl 3-methylpyridazine-4-carboxylate and aldimines, catalysed by the Lewis aci
- Muylaert, Koen,Mangelinckx, Sven,Jatczak, Martyna,De Coen, Laurens M.,Van Hecke, Kristof,Stevens, Christian V.
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p. 139 - 155
(2015/02/19)
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- Anion (fluoride)-doped ceria nanocrystals: Synthesis, characterization, and its catalytic application to oxidative coupling of benzylamines
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Fluoride doping in the CeO2 lattice has been achieved by a simple, reliable, reproducible, and safe solution-based method. F-containing CeO2 has retained the fluorite structure, and its effect has been confirmed from various analytical techniques such as powder X-ray diffraction, Fourier transform IR, Raman, UV-visible diffuse reflectance, photoluminescence (PL), and X-ray photoelectron spectroscopy (XPS), scanning electron microscopy-energy-dispersive X-ray (EDX) and transmission electron microscopy-EDX analysis. The concentration of fluoride in the CeO2 lattice has been determined from chemical analysis and core-level XPS analysis. The concentration of Ce3+ in the F-doped and undoped CeO2 samples have been determined both from XPS analysis as well as from variable-temperature magnetic susceptibility measurements. The characteristic Ce3+ emission in the PL spectrum indicated the increase of Ce 3+ ion concentration in the F-doped sample, conforming to the results from XPS and magnetic measurements. F-doped CeO2 nanocrystals showed moderate monodispersity as determined from particle-size measurements using dynamic light scattering experiments and high surface area of 106.1 m 2/g. Optical band gap of CeO2 has narrowed upon doping with fluoride ions from 3.05 to 2.95 eV. The formation of extrinsic oxygen vacancy complexes upon F-doping has been observed in the Raman spectrum (at 1097 cm-1) in addition to fingerprint bands of CeO2. The UV-shielding property and photocatalytic inactivity toward aqueous dye degradation process of F-doped CeO2 has suggested its potential use in cosmetic applications. Both F-doped CeO2 and CeO2 have been used as catalysts for oxidative coupling of benzylamines to imines in the presence of molecular oxygen under solvent-free conditions. F-doped CeO 2 exhibited better catalytic efficiency than CeO2. The oxidation procedure using these catalysts is simple, environmentally benign, and solvent-free, and the catalysts are reusable.
- Ahmad, Shahzad,Gopalaiah, Kovuru,Chandrudu, Sankala Naga,Nagarajan, Rajamani
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p. 2030 - 2039
(2014/03/21)
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- Tert-Butyl hydroperoxide (TBHP)-mediated oxidative self-coupling of amines to imines over a α-MnO2 catalyst
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We here demonstrate a simple, efficient and eco-friendly protocol for the direct synthesis of imines from amines via a facile α-MnO2 catalyzed-procedure at rt. Up to 13 benzylic, heterocyclic, and normal aliphatic imines were synthesized with 95-99% selectivity at 82-99% conversion. the Partner Organisations 2014.
- Zhang, Zhe,Wang, Feng,Wang, Min,Xu, Shutao,Chen, Haijun,Zhang, Chaofeng,Xu, Jie
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supporting information
p. 2523 - 2527
(2014/05/06)
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- Cu(I)/TEMPO-catalyzed aerobic oxidative synthesis of imines directly from primary and secondary amines under ambient and neat conditions
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By catalyst and condition screening, a simple Cu(I)/TEMPO-catalyst system was found to be an active and highly effective catalyst for the aerobic oxidation of amines to imines in open air at room temperature under neat conditions. This new method provided a mild, efficient, and practical alternative for the synthesis of the useful imines directly from primary and secondary amines.
- Huang, Bo,Tian, Haiwen,Lin, Shoushuai,Xie, Meihua,Yu, Xiaochun,Xu, Qing
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supporting information
p. 2861 - 2864
(2013/06/05)
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- Iron-catalyzed direct synthesis of imines from amines or alcohols and amines via aerobic oxidative reactions under air
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Abundant and cheap iron readily catalyzed the aerobic oxidative reactions of primary amines, secondary amines, benzylamines with anilines, and alcohols with amines by directly using air as the economic and safe oxidant, providing several direct, practical, and greener approaches for the preparation of useful imines.
- Zhang, Erlei,Tian, Haiwen,Xu, Sendong,Yu, Xiaochun,Xu, Qing
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supporting information
p. 2704 - 2707
(2013/07/19)
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- Selective autoxidation of benzylamines: Application to the synthesis of some nitrogen heterocycles
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A green and remarkably simple synthesis of nitrogen heterocycles from benzylamines and anilines o-substituted by a cyclizable group has been developed based on selective uncatalyzed autoxidation of benzylamines.
- Nguyen, Thanh Binh,Ermolenko, Ludmila,Al-Mourabit, Ali
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supporting information
p. 2713 - 2717
(2013/10/08)
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- Bodipy derivatives as organic triplet photosensitizers for aerobic photoorganocatalytic oxidative coupling of amines and photooxidation of dihydroxylnaphthalenes
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We used iodo-Bodipy derivatives that show strong absorption of visible light and long-lived triplet excited states as organic catalysts for photoredox catalytic organic reactions. Conventionally most of the photocatalysts are based on the off-the-shelf compounds, usually showing weak absorption in the visible region and short triplet excited state lifetimes. Herein, the organic catalysts are used for two photocatalyzed reactions mediated by singlet oxygen ( 1O2), that is, the aerobic oxidative coupling of amines and the photooxidation of dihydroxylnaphthalenes, which is coupled to the subsequent addition of amines to the naphthoquinones, via C-H functionalization of 1,4-naphthoquinone, to produce N-aryl-2-amino-1,4-naphthoquinones (one-pot reaction), which are anticancer and antibiotic reagents. The photoreactions were substantially accelerated with these new iodo-Bodipy organic photocatalysts compared to that catalyzed with the conventional Ru(II)/Ir(III) complexes, which show weak absorption in the visible region and short-lived triplet excited states. Our results will inspire the design and application of new organic triplet photosensitizers that show strong absorption of visible light and long-lived triplet excited state and the application of these catalysts in photoredox catalytic organic reactions.
- Huang, Ling,Zhao, Jianzhang,Guo, Song,Zhang, Caishun,Ma, Jie
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supporting information
p. 5627 - 5637
(2013/07/25)
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- Simple copper/TEMPO catalyzed aerobic dehydrogenation of benzylic amines and anilines
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CuBr2 with 2,2,6,6-tetramethylpiperidyl-1-oxy (TEMPO) has been successfully employed for the aerobic oxidation of primary and secondary benzyl amines in aqueous acetonitrile. Such catalytic systems have previously been used extensively in alcohol oxidation reactions. The same catalyst system was also used for oxidative cross-couplings of benzylamines with anilines. The electronic and steric properties of the aniline partner were found to be of crucial importance in determining reactivity or lack thereof. A mechanism for these reactions is proposed based on the data obtained to date. In the absence of benzyl amines, electron-rich anilines were found to undergo dehydrogenative coupling and yields of the resulting azo products could be increased by replacing CuBr2 with CuBr. No ligand (e.g. pyridine) is required for either reaction to proceed and presumably water and acetonitrile solvate the copper-containing intermediates.
- Hu, Zhenzhong,Kerton, Francesca M.
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supporting information; experimental part
p. 1618 - 1624
(2012/03/22)
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- Mimicking the environment of living organisms to achieve the oxidative coupling of amines to imines catalyzed by water-soluble metalloporphyrins
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Highly efficient procedure for preparing imines from the oxidative coupling of amines catalyzed by metalloporphyrins using water as the only solvent has been developed. Manganese porphyrin showed an excellent activity for the oxidative coupling of a wide
- Zhou, Xian-Tai,Ren, Qing-Gang,Ji, Hong-Bing
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scheme or table
p. 3369 - 3373
(2012/07/31)
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- Convenient and clean synthesis of imines from primary benzylamines
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The current syntheses of imines from benzylamines are often performed in organic solvents or under harsh reaction conditions. Clean oxidation of primary benzylamines to imines has been successfully achieved using H2O 2 in water at room temperature catalyzed by V2O 5. Among the 10 imine products, 5 of them precipitated from the reaction and led pure products after simple filtration. No organic solvents are needed in the whole process. The yields are good to quantitative. This represents an efficient and green procedure of the synthesis of imines. A similar green oxidation of benzylamines to aromatic aldehydes is also reported. A benzylic anion-involved mechanism is proposed based on the experiments.
- Chu, Guobiao,Li, Chunbao
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supporting information; experimental part
p. 4716 - 4719
(2010/11/24)
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