- Highly dispersed Mo-doped graphite carbon nitride: Potential application as oxidation catalyst with hydrogen peroxide
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A novel molybdenum-doped graphite carbon nitride (g-C3N4) catalyst was successfully prepared by simple calcination and applied to the oxidation of various substrates with hydrogen peroxide or tert-butylhydroperoxide (TBHP) as the oxidant. The morphology, structure, and chemical composition of the catalyst were characterized fully, demonstrating the presence of highly dispersed molybdenum species stabilized by the nitrogen atoms of g-C3N4. The Mo(vi) sites stabilized on the triazine ring of g-C3N4 interacted with H2O2 or TBPH, forming peroxo-Mo(vi) groups, which were active for oxidation. Mo-doped g-C3N4 exhibited significantly enhanced activity for the non-selective oxidation of methylene blue (MB) when compared with MoO3 or pure g-C3N4. Furthermore, the catalyst exhibited high efficiency for the selective oxidation of sulfides to sulfoxides, and N-compounds to the corresponding N-oxides, under mild conditions. The catalyst also showed potential application in the epoxidation of olefins. The effects of the homogeneous reaction of leached Mo and the recyclability of the catalyst were also evaluated. The data show that the catalyst exhibits great potential for various industrial applications.
- Gon?alves, Diogo A. F.,Alvim, Raquel P. R.,Bicalho, Hudson A.,Peres, Anderson M.,Binatti, Ildefonso,Batista, Pablo F. R.,Teixeira, Leonel S.,Resende, Rodrigo R.,Loren?on, Eudes
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- Fe-complex of a tetraamido macrocyclic ligand: Spectroscopic characterization and catalytic oxidation studies
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This work presents the spectroscopic characterization and reaction studies of a FeIII-complex (2) of a tetraamido macrocyclic ligand (1, 15,15-dimethyl-5,8,13,17-tetrahydro-5,8,13,17-tetraaza-dibenzo[a,g] cyclotridecene-6,7,14,16-tetraone). 2 was characterized primarily by means of EPR. In agreement with the magnetic moment (μeff = 3.87 BM), EPR spectroscopy of 2 shows signals consistent with S = 3/2 intermediate-spin ferric-iron. Besides EPR, mass spectrometry, UV/vis spectroscopy and cyclic voltammetry were used to further characterize 2. 2 is soluble in water and activates hydrogen peroxide under ambient conditions. 2 catalytically bleaches dyes, pulp and paper effluents and oxidizes several amines to their corresponding N-oxides with high turnover number and good yields.
- Sullivan, Shane Z.,Ghosh, Anindya,Biris, Alexandru S.,Pulla, Sharon,Brezden, Anna M.,Collom, Samulel L.,Woods, Ross M.,Munshi, Pradip,Schnackenberg, Laura,Pierce, Brad S.,Kannarpady, Ganesh K.
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- Perfluoropropylation of Furans, Thiophenes, and Pyridines with Bis(heptafluorobutyryl) Peroxide
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Bis(heptafluorobutyryl) peroxide (1) smoothly reacted with furans and thiophenes under mild conditions to regioselectively give 2-perfluoropropylfurans and thiophenes in high yields.Mechanistically, reactions with furans or thiophenes are considered to be initiated by one-electron transfers from substrates to 1.On the other hand, the perfluoropropylation of pyridine was proceeded by the usual free-radical substitution to a pyridinium salt by a heptafluoropropyl radical produced by the homolytic decomposition of 1.
- Sawada, Hideo,Yoshida, Masato,Hagh, Hidehiko,Aoshima, Kazuyoshi,Kobayashi, Michio
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- Effects of pyridine and its derivatives on the equilibria and kinetics pertaining to epoxidation reactions catalyzed by methyltrioxorhenium
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The coordination of substituted pyridines to MTO (methyltrioxorhenium) is governed by both electronic and steric effects. For example, the binding constant of pyridine to MTO is 200 L mol-1, whereas that of the better donor 4-picoline is 730 L mol-1 and that of the sterically encumbered 2,6- di-tert-butyl-4-methylpyridine is -1. A Hammett reaction constant ρ = -2.6, derived from meta- and para-substituted pyridine, applies to this equilibrium. Pyridine stabilizes the MTO/H2O2 system and accelerates the epoxidation of α-methylstyrene. The steady-state concentration of MTO is decreased during the catalytic epoxidation reaction by coordinating a pyridine derivative, thus stabilizing the MTO/H2O2 system against irreversible decomposition. Pyridine as a Lewis base accelerates the generation of the peroxorhehium catalysts, whereas coordination of pyridine to the diperoxorhenium complex appears responsible for the acceleration of epoxidation. Ultimately, however, it is the Bronsted basicity of pyridine that lowers the activity of hydronium ion, reducing the rate of epoxide ring opening.
- Wang, Wei-Dong,Espenson, James H.
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- Kinetics and Mechanism of the Oxidation of Pyridine by Caro's Acid Catalyzed by Ketones
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The kinetics of the oxidation of pyridine by peroxomonosulfate ion catalyzed by acetone and cyclohexanone has been investigated.The oxidation product was identified as pyridine 1-oxide, and the yield was found to be pH dependent.The rate law for the pyridine oxidation was shown to be .A mechanism involving a dioxirane intermediate which is consistent with the rate law has been postulated.Experiments leading to simplified forms of the rate law have been carried out.The ratios of rate constants kb/ka and ka'/ka were determined for both acetone and cyclohexanone.A side reaction, the Baeyer-Villiger process, is significant with cyclohexanone near pH 7.
- Gallopo, Andrew R.,Edwards, John O.
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- Formation and catalytic activity of novel water soluble di[ethylenediaminetetraacetato bis(N-oxido)] lanthanides
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Reaction of hydrogen peroxide with ethylenediaminetetraacetato lanthanides results in the formation of water-soluble isomorphous N-oxido ethylenediaminetetraacetato lanthanides K5[Ln(edtaO2) 2] · 12H2O [Ln = La (1), Ce (2), Nd (3), H 4edta = ethylenediaminetetraacetic acid C10H 16O8N2] in weak basic solution, where lanthanide ions are octa-coordinated by two quardentate N-oxido edta ligands, resulting in a distorted anti-tetragonal prism. Based on the comparisons of solid and solution 13C NMR spectra, these compounds are fully dissociated in solution. Catalytic reaction of K5[La(edtaO 2)2]·12H2O shows 96% conversion for the reaction of pyridine to pyridine N-oxide at 70 C.
- Jiang, Xue,Chen, Mao-Long,Yang, Yu-Chen,Zhou, Zhao-Hui
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- Immobilization of polyoxometalates on protonated graphitic carbon nitride: A highly efficient and reusable catalyst for the synthesis of pyridine-N-oxides
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N-oxides represent a significant class of compounds with increasing value due to their extensive applications in chemistry and biology. Herein, a series of heterogeneous catalysts were prepared based on the impregnation-precipitation method. In this strategy, protonated graphitic carbon nitride (pg-C3N4) was prepared first, and Cs3PW12O40 was immobilized over the surface of pg-C3N4 to obtain CsPW-CN composites. The prepared CsPW-CN composites achieved better catalytic activities than the pure Cs3PW12O40 in the N-oxidation of pyridine, and obtained 99% yield of pyridine-N-oxide in aqueous medium with H2O2 as a mild oxidant. Based on the characterizations of the catalyst morphology, structure, and chemical composition, the intimate interaction between Cs3PW12O40 and pg-C3N4 was verified. Meanwhile, the occurrence of the unique semi-embedded structure was an expected derivation of the pg-C3N4. Furthermore, the prepared CsPW-CN-1 composite was readily recovered and yielded 88.3% of the pyridine-N-oxide after 4 runs. This work could potentially provide a well-defined CsPW-CN composite for the N-oxidation of pyridine with a sustainable approach.
- Cai, Menglu,Cao, Wenhui,Chen, Yingqi,Dai, Liyan,Fang, Yangyang,Jia, Mingji,Song, Yujun,Wang, Xiaozhong,Yuan, Lei
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- Method for preparing sulfone and N-oxygen compound by using green and efficient oxidation system
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The invention discloses a method for preparing sulfone and N-oxygen compound by using a green and efficient oxidation system. The method comprises the following steps of: by using a tertiary amine compound or aromatic thioether or fatty thioether compound as a raw material, H2O2 as an oxidant, methanol as a reaction solvent and potassium carbonate as an alkali, introducing sulfuryl fluoride 5O2F2gas as an accelerator; performing stirring at room temperature under a sealed condition for oxidation reaction; and after finishing the reaction, filtering to remove solid potassium carbonate, dryingto remove water, filtering to obtain a crude product, and finally carrying out column chromatography separation to obtain a pure product. Tertiary amine is oxidized into an N-oxygen compound, and thethioether is oxidized into sulfone. According to the method, the sulfuryl fluoride (SO2F2) which is very cheap and easy to obtain is used as the reaction promoter, green and environment-friendly hydrogen peroxide (H2O2) is used as an oxidizing agent, and so that the yield of the reaction is generally high; after the reaction, byproducts are only water and inorganic salts (SO4 and F) whichare easy to remove and free of pollution, and the green and efficient oxidation system can be realized, and therefore, the method is suitable for large-scale industrial production.
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Paragraph 0039-0041
(2021/01/29)
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- SO2F2-mediated oxidation of primary and tertiary amines with 30% aqueous H2O2 solution
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A highly efficient and selective oxidation of primary and tertiary amines employing SO2F2/H2O2/base system was described. Anilines were converted to the corresponding azoxybenzenes, while primary benzylamines were transformed into nitriles and secondary benzylamines were rearranged to amides. For tertiary amine substrates quinolines, isoquinolines and pyridines, their oxidation products were the corresponding N-oxides. The reaction conditions are very mild and just involve SO2F2, amines, 30% aqueous H2O2 solution, and inorganic base at room temperature. One unique advantage is that this oxidation system is just composed of inexpensive inorganic compounds without the use of any metal and organic compounds.
- Liao, Xudong,Zhou, Yi,Ai, Chengmei,Ye, Cuijiao,Chen, Guanghui,Yan, Zhaohua,Lin, Sen
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supporting information
(2021/11/01)
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- Method for synthesizing pyridine-N-oxide through catalytic oxidation by continuous non-solvent method
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The invention discloses a method for synthesizing pyridine-N-oxide through catalytic oxidation by a continuous non-solvent method, and belongs to the field of chemical synthesis. The method is characterized by comprising the following steps: mixing metered pyridine or alkyl pyridine with an oxidizing agent in proportion, carrying out a reaction in a continuous tubular reactor filled with an immobilized catalyst, and distilling off excess water after the reaction is finished to obtain a pyridine-N-oxide or alkyl pyridine-N-oxide product, wherein the catalyst is cross-linked polystyrene resin immobilized with active substance anions and has a quaternary ammonium salt group. Compared with the prior art, the method for synthesizing the pyridine-N-oxide through catalytic oxidation by the continuous non-solvent method can realize continuous production of the pyridine-N-oxide, is environment-friendly, energy-saving and high in conversion rate, and has very good promotion and application values.
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Paragraph 0037-0043
(2020/08/06)
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- The M?CPbA?NH3(G) system: A safe and scalable alternative for the manufacture of (substituted) pyridine and quinoline N?oxides?
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An improved, safe, and scalable isolation process for (substituted) pyridine and quinoline N-oxides in quantitative yields along with high purities using the m-CPBA?NH3(g) system is described. The safety was assessed by reaction calorimetry and differential scanning calorimetry studies for possible hazards during the conversion and isolation steps. Careful interpretation of the data substantiated the safety and scalability. The process flow is simplified to meet the industrial requirements of safety, cost-effectiveness, and utility minimization. The reaction was safely demonstrated at a 2.5 kg scale.
- Palav, Amey,Misal, Balu,Ernolla, Anilkumar,Parab, Vinod,Waske, Prashant,Khandekar, Dileep,Chaudhary, Vinay,Chaturbhuj, Ganesh
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supporting information
p. 244 - 251
(2019/03/17)
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- Novel synthetic method of sodium pyrithione
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The invention discloses a novel synthetic method of sodium pyrithione. The method includes the following steps: synthesizing a pyridine n-oxide by using pyridine as a raw material, water as a solventand hydrogen peroxide as an oxidant in the presence of catalysts; and mixing the pyridine n-oxide with organic solvents, adding surfactants, vulcanizing agents and alkali reagents, refluxing water, and raising the temperature and pressurizing for reaction after water in the reaction system is separated to synthesize the sodium pyrithione. The novel synthetic method of sodium pyrithione uses the cheap pyridine as the raw material, has the advantages of easily available raw material, simply synthesis route, high total reaction yield, less ''three wastes'' generated by the reaction and low synthesis cost, and has extremely high industrial value.
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Paragraph 0038-0039; 0041-0042; 0044-0045; 0047-0048; 0050-
(2019/05/08)
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- Method for preparing azaheterocycle-N-oxides
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The invention relates to a method for preparing azaheterocycle-N-oxides. The method is concretely characterized in that pyridine, quinoline and isoquinoline compounds, which are used as raw materials,are oxidized under the action of a catalyst to obtain the corresponding N-oxides. The method for preparing azaheterocycle-N-oxides is a preparation method having the advantages of high yield, low cost, easiness in operation, and suitableness for industrialization.
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Paragraph 0030-0031
(2019/09/14)
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- A Biocatalytic Synthesis of Heteroaromatic N-Oxides by Whole Cells of Escherichia coli Expressing the Multicomponent, Soluble Di-Iron Monooxygenase (SDIMO) PmlABCDEF
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Aromatic N-oxides (ArN?OX) are desirable biologically active compounds with a potential for application in pharmacy and agriculture industries. As biocatalysis is making a great impact in organic synthesis, there is still a lack of efficient and convenient enzyme-based techniques for the production of aromatic N-oxides. In this study, a recombinant soluble di-iron monooxygenase (SDIMO) PmlABCDEF overexpressed in Escherichia coli was showed to produce various aromatic N-oxides. Out of 98 tested N-heterocycles, seventy were converted to the corresponding N-oxides without any side oxidation products. This whole-cell biocatalyst showed a high activity towards pyridines, pyrazines, and pyrimidines. It was also capable of oxidizing bulky N-heterocycles with two or even three aromatic rings. Being entirely biocatalytic, our approach provides an environmentally friendly and mild method for the production of aromatic N-oxides avoiding the use of strong oxidants, organometallic catalysts, undesirable solvents, or other environment unfriendly reagents. (Figure presented.).
- Petkevi?ius, Vytautas,Vaitekūnas, Justas,Taurait?, Daiva,Stankevi?iūt?, Jonita,?arlauskas, Jonas,??nas, Narimantas,Me?kys, Rolandas
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supporting information
p. 2456 - 2465
(2019/01/25)
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- Exogenous-oxidant-and catalyst-free electrochemical deoxygenative C2 sulfonylation of quinoline: N-oxides
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An exogenous-oxidant-and catalyst-free electrochemical deoxygenative C2 sulfonylation reaction has been achieved. By employing quinoline N-oxides as the starting materials, the electrochemical C-H sulfonylation of electron-deficient quinolines was indirectly achieved at room temperature and a variety of sulfonylated quinoline derivatives were synthesized in modest to high yield with excellent regioselectivity. Notably, this protocol is the first example for synthesizing sulfonylated electron-deficient heteroarenes/arenes through electrochemistry.
- Jiang, Minbao,Yuan, Yong,Wang, Tao,Xiong, Yunkui,Li, Jun,Guo, Huijiao,Lei, Aiwen
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supporting information
p. 13852 - 13855
(2019/11/21)
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- A mild and efficient H2O2 oxygenation of N-heteroaromatic compounds to the amine N-oxides and KI deoxygenation back to the tertiary amine with hexaphenyloxodiphosphonium triflate
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A mild and efficient method for the oxidation of N-heteroaromatic compounds to the corresponding N-oxides using H2O2 in the presence of hexaphenyloxodiphosphnium triflate (Hendrickson reagent) in EtOH at room temperature was reported. This methodology presented relatively fast and selective reactions to afford the N-oxides in good yields. The reverse reactions, deoxygenation reactions, were also carried out under the same reaction conditions by KI to produce the tertiary amines.
- Khodaei, Mohammad Mehdi,Alizadeh, Abdolhamid,Hezarkhani, Hadis Afshar
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p. 1843 - 1849
(2018/07/06)
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- Pyridine synthesis of heterocyclic nitrogen oxide
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The invention provides a synthesis method of pyridine heterocycle oxynitrides, which comprises the following steps: mixing a catalyst {Mo132}, pyridine compounds and 30% hydrogen peroxide in a mole ratio of 1:143:714 in a mixed solvent composed of ethanol and water in a volume ratio of 2:3 at room temperature to react for 6-24 hours, extracting with a dichloromethane organic solvent, and purifying by distilling with an organic phase dichloromethane to obtain the pyridine heterocycle oxynitride product. Compared with the past systems, the catalytic system can complete the catalytic oxidation of the pyridine compounds and quinoline compounds at room temperature within a short time, is reusable and has high yield.
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Paragraph 0012-0015
(2017/08/25)
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- A pyridine nitrogen oxide high-efficient, multi-phase catalytic preparation method
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The invention discloses a high efficient heterogeneous catalytic preparation method of pyridine oxynitride. In the provided preparation method, mono-substituted or poly-substituted pyridines or pyridine derivatives are taken as the primary raw materials, titanium dioxide loaded on tungsten (WO3/TiO2) is taken as the catalyst, hydrogen peroxide is taken as the oxidizing agent, and reactions are carried out in a water solution at a room temperature so as to obtain the target product. Compared with the prior art, the preparation method has the following advantages: (1) the provided oxidation method, no acetic acid is used, and thus the requirements on equipment are greatly reduced; (2) a heterogeneous catalytic method is adopted to prepare pyridine oxynitride, the catalyst can be separated from the reaction system through simple filtration or centrifugation, and the operation is convenient; (3) titanium dioxide loaded on tungsten is taken as the catalyst, pyridine oxynitride is prepared by one step in a water solution at a room temperature, the reaction conditions are mild, and the pollution to the environment is little.
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Paragraph 0153; 0157; 0158; 0159
(2017/08/25)
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- Mild, one-pot preparation of 2-substituted benzimidazoles from organic halides
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Alkyl halides are feasibly transformed into benzimidazoles by a domino reaction under solvent-free conditions. The organic halides react with o-phenylenediamines in stoichiometric amounts in the presence of pyridine-N-oxide to produce the desired substituted benzimidazoles. This domino synthesis does not require catalysts. The synthesis occurs in dry medium and the environmental impact is minimal. The method provides products without intermediate separation. A mechanism of benzimidazole synthesis is also proposed.
- Br?tulescu, George
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supporting information
p. 811 - 817
(2017/04/06)
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- Copper-Catalyzed Direct, Regioselective Arylamination of N-Oxides: Studies to Access Conjugated π-Systems
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An efficient copper(I)-catalyzed direct regioselective arylamination of various heterocyclic N-oxides was achieved successfully under redox-neutral conditions using anthranils as arylaminating reagents. The developed protocol is simple, straightforward, and economic with a broad range substrate scope. The dual functional groups in the final molecules were utilized to construct structurally and functionally diverse nitrogen-containing organic π-conjugated systems.
- Biswas, Aniruddha,Karmakar, Ujjwal,Nandi, Shiny,Samanta, Rajarshi
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p. 8933 - 8942
(2017/09/11)
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- Catalyst-free and selective oxidation of pyridine derivatives and tertiary amines to corresponding N-oxides with 1,2-diphenyl-1,1,2,2-tetrahydroperoxyethane
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The catalyst-free oxidation of various pyridine derivatives and tertiary amines to their corresponding N-oxides with 1,1,2,2-tetrahydroperoxy-1,2-diphenylethane as an efficient oxidant has been developed. The methodology proved to tolerate a number of functional groups. The reactions proceeded smoothly under solvent-free and mild conditions at room temperature. All the products were easily extracted from the reaction mixtures in excellent yields. Graphical abstract: The catalyst-free oxidation of various pyridine derivatives and tertiary amines to their corresponding N-oxides with 1,1,2,2-tetrahydroperoxy-1,2-diphenylethane as an efficient oxidant has been developed. The methodology proved to tolerate a number of functional groups. The reactions proceeded smoothly under solvent-free and mild conditions at room temperature. All the products were easily extracted from the reaction mixtures in excellent yields.
- Azarifar, Davood,Mahmoudi, Boshra
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p. 645 - 651
(2016/02/19)
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- A lipase-glucose oxidase system for the efficient oxidation of: N -heteroaromatic compounds and tertiary amines
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In this work, a lipase-glucose oxidase system has been designed and proven to be an efficient system for the oxidation of N-heteroaromatic compounds and tertiary amines. This dual-enzyme system not only displays environmental friendliness, but also demonstrates its huge potential in industrial applications.
- Yang, Fengjuan,Zhang, Xiaowen,Li, Fengxi,Wang, Zhi,Wang, Lei
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supporting information
p. 3518 - 3521
(2016/07/06)
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- Renewable waste rice husk grafted oxo-vanadium catalyst for oxidation of tertiary amines to N-oxides
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Low cost renewable waste rice husks (RH) have been used as a support for grafting of an oxo-vanadium Schiff base via covalent attachment for the oxidation of tertiary amines to N-oxide. The synthesis of the desired RH grafted oxo-vanadium complex involves prior functionalization of the RH support with amino-propyltrimethoxysilane (APTMS) followed by its reaction with salicylaldehyde to get an RH-functionalized Schiff base which subsequently reacted with vanadyl sulphate to get the targeted oxo-vanadium catalyst. The synthesized catalyst was found to be an efficient heterogeneous catalyst and afforded an excellent yield of corresponding N-oxides via oxidation of tertiary amines with hydrogen peroxide as an oxidant. Furthermore, the synthesized catalyst was found to be quite stable and showed consistent activity for five runs without any loss in activity.
- Panwar, Vineeta,Bansal, Ankushi,Ray, Siddharth S.,Jain, Suman L.
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p. 71550 - 71556
(2016/08/05)
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- Base free regioselective synthesis of α-triazolylazine derivatives
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A regioselective α-heteroarylation followed by deoxygenation towards the synthesis of variety of azine triazole from simple azine N-oxides derivatives and N-tosyl-1,2,3-triazoles has been described. The reaction is metal free and base free with shorter reaction time, high yields and a broad substrate scope.
- Harisha, Mysore Bhyrappa,Nagaraj, Muthupandi,Muthusubramanian, Shanmugam,Bhuvanesh, Nattamai
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p. 58118 - 58124
(2016/07/06)
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- Metal-Free, Phosphonium Salt-Mediated Sulfoximination of Azine N-Oxides: Approach for the Synthesis of N-Azine Sulfoximines
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Herein, we report a simple and metal-free method for the synthesis of N-azine sulfoximines by the nucleophilic substitution of azine N-oxides with NH-sulfoximines. The present method works at room temperature with wide functional group compatibility and gives several unprecedented N-azine sulfoximines. The reaction conditions were also found suitable with enantiopure substrates and furnished products without any racemization. It also finds an application in the sulfoximination of azine-based functional molecules such as 2,2′-bipyridine, 1,10-phenanthroline, and quinine.
- Aithagani, Sravan Kumar,Kumar, Mukesh,Yadav, Mahipal,Vishwakarma, Ram A.,Singh, Parvinder Pal
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p. 5886 - 5894
(2016/07/23)
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- Benzylation of heterocyclic N-oxides via direct oxidative cross-dehydrogenative coupling with toluene derivatives
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A novel cross-dehydrogenative coupling (CDC) of heterocyclic N-oxides with toluene derivatives has been discussed, allowing for the facile synthesis of a broad range of structurally diverse C1-benzyl quinoline N-oxides, isoquinoline N-oxides and pyridine N-oxides, including two methylated quinoline N-oxides in particular. This protocol not only extends the application of toluenes in synthetic organic chemistry, but also offers an alternative method to prepare benzylated heterocyclic N-oxides without any metal involved, which is important in medicinal chemistry.
- Wan,Qiao,Sun,Di,Fang,Li,Guo
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supporting information
p. 10227 - 10232
(2016/12/07)
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- The microwave-assisted ortho-alkylation of azine N-oxides with N-tosylhydrazones catalyzed by copper(i) iodide
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A copper catalyzed regioselective cross-coupling of N-tosylhydrazones with azine N-oxides to yield ortho-alkylated products in moderate to good yields is reported. The reaction is facilitated by microwave, takes place without any ligand, and uses inexpensive copper(i) iodide as the catalyst.
- Jha, Abadh Kishor,Jain, Nidhi
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supporting information
p. 1831 - 1834
(2016/02/05)
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- Metal-Free Oxidation of Primary Amines to Nitriles through Coupled Catalytic Cycles
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Synergism among several intertwined catalytic cycles allows for selective, room temperature oxidation of primary amines to the corresponding nitriles in 85-98 % isolated yield. This metal-free, scalable, operationally simple method employs a catalytic quantity of 4-acetamido-TEMPO (ACT; TEMPO=2,2,6,6-tetramethylpiperidine N-oxide) radical and the inexpensive, environmentally benign triple salt oxone as the terminal oxidant under mild conditions. Simple filtration of the reaction mixture through silica gel affords pure nitrile products.
- Lambert, Kyle M.,Bobbitt, James M.,Eldirany, Sherif A.,Kissane, Liam E.,Sheridan, Rose K.,Stempel, Zachary D.,Sternberg, Francis H.,Bailey, William F.
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supporting information
p. 5156 - 5159
(2016/04/09)
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- Selective Oxidation with Aqueous Hydrogen Peroxide by [PO4{WO(O2)2}4]3- Supported on Zinc-Modified Tin Dioxide
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We prepared supported phosphorus-containing tetranuclear peroxotungstate ([PO4{WO(O2)2}4]3-, denoted by PW4) catalysts by using zinc-modified SnO2 supports with different zinc contents [PW4-Zn(x)/SnO2, in which x denotes the zinc content (wt%)]. The supported catalysts, in particular PW4-Zn(0.8)/SnO2, could act as efficient and reusable heterogeneous catalysts for selective oxidation with aqueous H2O2 as the terminal oxidant. The catalytic performance of PW4-Zn(0.8)/SnO2 was much superior to those of the corresponding homogeneous analogue THA3PW4 (THA=tetra-n-hexylammonium) and the previously reported tungstate-based heterogeneous catalysts such as our W-Zn/SnO2. In the presence of PW4-Zn(0.8)/SnO2, various types of organic substrates such as alkenes, amines, silanes, and sulfides could be converted into the corresponding oxygenated products in high to excellent yields by using near-stoichiometric amounts of H2O2 with respect to the substrates (typically 1.2 equiv.). The PW4 species interacting with highly dispersed Zn2+ species on SnO2 likely plays an important role in the present oxidation.
- Nojima, Susumu,Kamata, Keigo,Suzuki, Kosuke,Yamaguchi, Kazuya,Mizuno, Noritaka
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p. 1097 - 1104
(2015/04/14)
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- Facile Immobilization of a Lewis Acid Polyoxometalate onto Layered Double Hydroxides for Highly Efficient N-Oxidation of Pyridine-Based Derivatives and Denitrogenation
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N-Oxides are a class of highly important compounds that are used widely as synthetic intermediates. In this paper, we demonstrate for the first time the use of a polyoxometalate-based composite material as a highly efficient heterogeneous catalyst for the N-oxidation of pyridines and its derivatives in the presence of H2O2 at room temperature. The composite was prepared by the intercalation of the [La(PW11O39)2]11- anion into a layered double hydroxide (LDH) modified with tris(hydroxymethyl)aminomethane (Tris). Additionally, the Tris-LDH-La(PW11)2-based catalyst has been employed for the denitrogenation of a model oil mixture in the presence of 1-butyl-3-methylimidazolium tetrafluoroborate and H2O2. Denitrogenation can be achieved in 40 min at 75 C. Finally, the heterogeneous catalyst can be recovered easily and reused at least 10 times without a measurable decrease of the catalytic activity and disintegration of the Tris-LDH-La(PW11)2 structure. Between the sheets: We demonstrate for the first time the use of a polyoxometalate-based composite material as a highly efficient heterogeneous catalyst for the N-oxidation of pyridines and its derivatives in the presence of H2O2 at room temperature. The composite is prepared by the intercalation of the [La(PW11O39)2]11- anion into a layered double hydroxide modified with tris(hydroxymethyl)aminomethane.
- Liu, Kai,Yao, Zhixiao,Miras, Haralampos N.,Song, Yu-Fei
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p. 3903 - 3910
(2016/01/26)
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- Catalytic system for pyridine oxidation to N-oxides under mild conditions based on polyoxomolybdate
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A reusable and effective catalytic system has been developed for oxidation of pyridines catalyzed by Keplerate polyoxomolybdate ({Mo132}) at room temperature. Pyridine compounds could be oxidized in high yields under mild conditions.
- Yang, Chunxia,Zhao, Wei,Cheng, Zhiguo,Luo, Baomin,Bi, Dongqin
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p. 36809 - 36812
(2015/05/05)
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- Carbon nanofibers decorated with oxo-rhenium complexes: Highly efficient heterogeneous catalyst for oxidation of amines with hydrogen peroxide
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Pyridine functionalized carbon nanofibers (Py-CNFs) were synthesized, characterized and used for the grafting of oxo-rhenium complex i.e., methyltrioxorhenium (MTO) via acid-base ionic interaction. The grafting of MTO to Py-CNFs was confirmed by FTIR, UV-vis, SEM, TEM and TGA analyses. The determination of rhenium content by ICP-AES further suggested the successful immobilization of MTO to the support. The developed heterogeneous material i.e., MTO@Py-CNFs was found to be an efficient catalyst for the oxidation of various secondary as well as tertiary amines to corresponding nitrones or N-oxides, respectively by using hydrogen peroxide. The developed catalyst was readily recovered by centrifugation and reused for subsequent ten runs without any significant loss in catalytic activity.
- Verma, Sanny,Kumar, Subodh,Shawat, Efrat,Nessim, Gilbert Daniel,Jain, Suman L.
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- Metal-free methylation of a pyridine N-oxide C-H bond by using peroxides
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Metal-free methylation of a pyridine N-oxide C-H bond was developed using peroxide as a methyl reagent under neat conditions. Pyridine N-oxide derivatives with various groups (e.g., Cl, NO2, and OCH3) were all suitable substrates, and the desired products were obtained in moderate to excellent yields under standard conditions. Moreover, the methylation can be performed with a good yield on the gram-scale experiment. Tentative mechanistic studies show that the methylation is a classical radical process.
- Li, Gang,Yang, Suling,Lv, Bingjie,Han, Qingqing,Ma, Xingxing,Sun, Kai,Wang, Zhiyong,Zhao, Feng,Lv, Yunhe,Wu, Hankui
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supporting information
p. 11184 - 11188
(2015/11/27)
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- 2,2,2-Trifluoroacetophenone as an organocatalyst for the oxidation of tertiary amines and azines to N-oxides
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A cheap, mild and environmentally friendly oxidation of tertiary amines and azines to the corresponding Noxides is reported by using polyfluoroalkyl ketones as efficient organocatalysts. 2,2,2-Trifluoroacetophenone was identified as the optimum catalyst for the oxidation of aliphatic tertiary amines and azines. This oxidation is chemoselective and proceeds in high-to-quantitative yields utilizing 10 mol% of the catalyst and H2O2 as the oxidant.
- Limnios, Dimitris,Kokotos, Christoforos G.
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supporting information
p. 559 - 563
(2014/04/03)
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- Insights into the mechanistic and synthetic aspects of the Mo/P-catalyzed oxidation of N-heterocycles
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A Mo/P catalytic system for an efficient gram-scale oxidation of a variety of nitrogen heterocycles to N-oxides with hydrogen peroxide as terminal oxidant has been investigated. Combined spectroscopic and crystallographic studies point to the tetranuclear Mo4P peroxo complex as one of the active catalytic species present in the solution. Based on this finding an optimized catalytic system has been developed. The utility and chemoselectivity of the catalytic system has been demonstrated by the synthesis of over 20 heterocyclic N-oxides.
- Larionov, Oleg V.,Stephens, David,Mfuh, Adelphe M.,Arman, Hadi D.,Naumova, Anastasia S.,Chavez, Gabriel,Skenderi, Behije
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p. 3026 - 3036
(2014/05/06)
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- Green and reusable synthetic procedure for pyridine N-oxides catalyzed by a lacunary polyoxometalate
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A lacunary Keggin polyoxometalate of K8[BW11O39H] · 13H2O was used as an effective and reusable catalyst for pyridine oxidation. Good yields of pyridine N-oxides were obtained in this catalytic system with hydrogen peroxide in water under mild conditions. Taylor and Francis Group, LLC.
- Zhao, Wei,Wang, Xing,Yang, Chunxia
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p. 150 - 160
(2013/11/06)
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- Trichloroacetonitrile-hydrogen peroxide: A simple and efficient system for the selective oxidation of tertiary and secondary amines
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A variety of tertiary and secondary amines were efficiently oxidized to their corresponding N-oxides and nitrones, respectively, using the trichloroacetonitrile-hydrogen peroxide system. The in situ generated trichloromethylperoxyimidic acid is the active reagent for the oxidation processes.
- Nikbakht, Fatemeh,Heydari, Akbar
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p. 2513 - 2516
(2014/05/06)
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- Grafting of a rhenium-oxo complex on Schiff base functionalized graphene oxide: An efficient catalyst for the oxidation of amines
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A rhenium-oxo complex such as methyltrioxorhenium (MTO) has been homogeneously immobilized on a Schiff base modified graphene oxide (GrO) support via covalent bonding. The loading of MTO on GrO nanosheets was monitored by FTIR, TG-DTA, and elemental analyses. The developed heterogeneous catalyst is found to be efficient for the oxidation of various amines to the corresponding N-oxides using hydrogen peroxide as an oxidant in high to excellent yields. At the end of the reaction, the catalyst is readily recovered by filtration and reused for subsequent runs. After the third run, the catalyst showed a marginal decrease in catalytic activity owing to the leaching of the MTO complex from the support. This journal is the Partner Organisations 2014.
- Khatri, Praveen K.,Choudhary, Shivani,Singh, Raghuvir,Jain, Suman L.,Khatri, Om P.
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p. 8054 - 8061
(2014/05/20)
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- Phosphoric acid modified montmorillonite clay: A new heterogeneous catalyst for nitration of arenes
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The easily available montmorillonite clay is treated with phosphoric acid and 10 wt.% is found to be the optimum concentration of phosphoric acid that can be adsorbed chemically on the surface of the clay. Acidity of this phosphoric acid treated montmorillonite clay (PAM) is determined by volumetric as well as potentiometric titration and characterized. Catalytic efficacy of PAM in nitration of various aromatic compounds is reported.
- Bharadwaj, Saitanya K.,Boruah, Purna K.,Gogoi, Pradip K.
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p. 124 - 128
(2014/12/11)
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- A facile synthetic route for antineoplastic drug GDC-0449
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In the current study a facile synthetic route for preparing antineoplastic drug GDC-0449 is investigated. Starting with pyridine-1-oxide and 1-iodo-3-nitrobenzene, the intermediate product 2-(2-chloro-5-nitrophenyl) pyridine was prepared by cross-coupling
- Cao, Meng,Hu, Hua-You,Zhao, Hu-Cheng,Zhang, Xi-Quan,Gu, Hong-Mei,Yang, Ling,Cai, Jin,Wang, Peng,Hu, Bing,Ji, Min
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p. 1408 - 1414
(2014/07/21)
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- The oxidation of pyridines catalyzed by surfactant-encapsulated polyoxometalate [(C18H37)2(CH3) 2N]8[HBW11O39] with the temperature-responsive property of solubility
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Temperature-responsive characterization of solubility based on a surfactant-encapsulated polyoxometalate ([(C18H37) 2(CH3)2N]8[HBW11O 39]) in tert-butyl alcohol was described and used in catalytic oxidation of pyridines. The catalyst could be recovered and reused several times by controlling the temperature.
- Zhao, Wei,Yang, Chunxia,Ding, Yong,Ma, Baochun
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p. 2614 - 2618
(2013/09/12)
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- A green catalytic procedure for oxidation of pyridines catalyzed by a lacunary polyoxometalate in water at room temperature
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A green and reusable catalytic procedure for oxidation of pyridines to N-oxides was developed. High yields of heterocyclic N-oxides were obtained when catalyzed by Δ-Na8HPW9O34 in water at room temperature. The catalyst used in the system could be recovered and reused several times without obvious loss of activity.
- Zhao, Wei,Yang, Chunxia
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supporting information
p. 1867 - 1870
(2013/10/08)
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- Oxidation of alcohols and pyridines by a water-soluble polyoxometalate with hydrogen peroxide
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A water-soluble catalyst based on a silicotungstate polyoxometalate, K 8[β-SiW11O39] · 14H2O, was developed for the oxidation of pyridines and alcohols with hydrogen peroxide. The reactions were carried out in water, and good yields of the corresponding heterocyclic N-oxides and ketones were obtained under relatively mild conditions. The catalyst could be easily recovered by extraction with ethyl acetate and reused several times. Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications to view the free supplemental file.
- Zhang, Zhenxin,Zhu, Qianqian,Ding, Yong
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supporting information
p. 1211 - 1218
(2013/03/29)
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- Silver-catalyzed 2-pyridyl arylation of pyridine N-oxides with arylboronic acids at room temperature
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A novel direct arylation of pyridine N-oxides with arylboronic acids through C-H functionalization has been developed. This new reaction is performed at room temperature using catalytic silver(I) nitrate in the presence of potassium persulfate and give 2-
- Mai, Wenpeng,Yuan, Jinwei,Li, Zhicheng,Sun, Gangchun,Qu, Lingbo
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supporting information; experimental part
p. 145 - 149
(2012/02/04)
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- Efficient heterogeneous epoxidation of alkenes by a supported tungsten oxide catalyst
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Oxidation optimization: A combination of tungsten and zinc oxides on a SnO2 support (W-Zn/SnO2) is a heterogeneous and reusable solid catalyst for selective oxidation with aqueous H2O2. With it, various substrates, such as alkenes, amines, silanes, and sulfides, were oxidized into the corresponding products in high yields (see scheme). The catalyst can be reused several times without an appreciable loss in catalytic performance. Copyright
- Kamata, Keigo,Yonehara, Koji,Sumida, Yasutaka,Hirata, Kazuhisa,Nojima, Susumu,Mizuno, Noritaka
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supporting information; scheme or table
p. 12062 - 12066
(2012/02/03)
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- Method of synthesis of tetradentate amide macrocycle ligand and its metal-complex
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A tetradendate amide based macrocyclic ligand and its Fe(III) complex which act as activators of hydrogen peroxide. The synthetic methodology to develop the ligands is new, simple and provides better yield for each step of the ligand synthesis. The Fe(III
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Page/Page column 3
(2011/05/05)
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- The oxidation of pyridine and alcohol using the Keggin-type lacunary polytungstophosphate as a temperature-controlled phase transfer catalyst
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A novel temperature-controlled phase transfer catalyst of [(C 18H37)2(CH3)2N] 7[PW11O39] has been developed for the oxidation of pyridines and alcohols with hydrogen peroxide. The reactions were conducted in 1,4-dioxane, and high yields of the corresponding heterocyclic N-oxides and ketones were obtained under relative mild conditions. The catalyst could be easily recovered and reused after reaction with cooling. There was no discernable loss in activity and selectivity after several reaction cycles.
- Ding, Yong,Zhao, Wei
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experimental part
p. 45 - 51
(2011/04/24)
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- Influence of a reaction medium on the oxidation of aromatic nitrogen-containing compounds by peroxyacids
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The influence of different solvents on the oxidation reaction rate of pyridine (Py), quinoline (QN), acridine (AN), α-oxyquinoline (OQN) and a-picolinic acid (APA) by peroxydecanoic acid (PDA) was studied. It was found that the oxidation rate grows in the series Py eq) and its decomposition constant (k2) in acetone and benzene were calculated. It was shown that the nature of the solvent influences the numerical values of both Kp and k2. It was established that introduction of acetic acid (which is able to form compounds with Py) into the reaction medium slows the rate of the oxidation process drastically. Correlation equations linking the polarity, polarizability, electrophilicity, and basicity of solvents with the constant of the PDA oxidation reaction rate for Py were found. It was concluded that the basicity and polarity of the solvent have a decisive influence on the oxidation reaction rate, while the polarizability and electrophilicity of the reaction medium do not influence the oxidation reaction rate. Pleiades Publishing, Ltd., 2011.
- Dutka,Matsyuk,Dutka
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scheme or table
p. 45 - 50
(2011/06/18)
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- Mild and recyclable catalytic oxidation of pyridines to N-oxides with H2O2 in water mediated by a vanadium-substituted polyoxometalate
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A vanadium-substituted polyoxometalate, K6[PW9V 3O40]·4H2O, was used as a recyclable and effective catalyst for the oxidation of pyridines. The reactions were successfully conducted in water under mild conditions. The catalyst could be easily recovered and reused.
- Ding, Yong,Zhao, Wei,Song, Wenfeng,Zhang, Zhenxin,Ma, Baochun
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supporting information; experimental part
p. 1486 - 1489
(2011/08/03)
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- Organic salts of polyoxometalates: Novel and efficient catalysts for the synthesis of pyridine n-oxide derivatives
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Catalytic N-oxidation of pyridine derivatives to related N-oxides were performed in the peresence of three organic salts of polyoxometalates including two heteropolyanion (THA)7.7H6.3[NaP5W 30O110], 1, and (THPA)7.5 H 6.5[NaP5W30O110], 2, and one isopolyanion [TBA]2[W6O19] (3) with W as central metal atom. Catalyst (3) showed the best catalytic activity. The highly selective oxidation gave good to excellent yields of the related N-oxides along with decarboxylation at 2-position of pyridine ring. The effect of some operative variables, such as temperature, various solvents, and the reaction time was studied. The reaction conditions were optimized. Copyright Taylor & Francis Group, LLC.
- Tavakoli-Hoseini, Niloofar,Bamoharram, Fatemeh F.,Heravi, Majid M.
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experimental part
p. 912 - 915
(2011/02/28)
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- Oxidation of organic compounds by sulfonated porous carbon and hydrogen peroxide
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The oxidation of organic compounds by sulfonated porous carbon and H 2O2 was studied at room temperature. Alkyl and aryl sulfides were oxidized to the corresponding sulfoxides or sulfones in excellent yields. Secondary alcohols were also converted to the corresponding esters/lactones and aldehydes to methyl esters in good yields. Moreover, aliphatic tertiary amines and substituted pyridines were oxidized to N-oxides.
- Shokrolahi, Arash,Zali, Abbas,Keshavarz, Mohammad Hossein
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experimental part
p. 1427 - 1432
(2012/04/18)
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- Probing 'spin-forbidden' oxygen-atom transfer: Gas-phase reactions of chromium-porphyrin complexes
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Oxygen-atom transfer reactions of metalloporphyrin species play an important role in biochemical and synthetic oxidation reactions. An emerging theme in this chemistry is that spin-state changes can play important roles, and a 'two-state' reactivity model
- Crestoni, Maria Elisa,Fornarini, Simonetta,Lanucara, Francesco,Warren, Jeffrey J.,Mayer, James M.
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experimental part
p. 4336 - 4343
(2010/05/14)
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- Selective oxidation of pyridine to pyridine-N-oxide with hydrogen peroxide over Ti-MWW catalyst
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The oxidation of pyridine to pyridine-N-oxide (PNO) with hydrogen peroxide has been investigated on various titanosilicate catalysts. Superior to other titanosilicates like TS-1, Ti-Beta and Ti-MOR, Ti-MWW showed a higher catalytic activity and product se
- Xie, Wei,Zheng, Yuting,Zhao, Song,Yang, Junxia,Liu, Yueming,Wu, Peng
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experimental part
p. 114 - 118
(2011/01/04)
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