- Synthesis of Alkyl Substituted p-Benzoquinones from the Corresponding Phenols Using Molecular Oxygen Catalyzed by Copper(II) Chloride-Amine Hydrochloride Systems
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2,4,6-Trimethylphenol was effectively oxidized to trimethyl-p-benzoquinone with molecular oxygen in the presense of a catalytic amount of copper(II) chloride-amines in alcohol at ambient temperature.Various amines could be used as a co-catalyst in the presence of acids, and especially hydroxylamine hydrochloride and acetone oxime coupled with hydrochloric acid showed high activity. 2,6-Dimethyl-p-benzoquinone was also obtained from 2,6-dimethylphenol in good yield in this catalytic oxidation system.
- Shimizu, Masao,Watanabe, Yoshihito,Orita, Hideo,Hayakawa, Takashi,Takehira, Katsuomi
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- A novel oxygenation of 2,3,6-trimethylphenol to trimethyl-p-benzoquinone by dioxygen with copper(II) chloride/amine hydrochloride catalyst
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2,3,6-Trimethylphenol was efficiently oxygenated to trimethyl-p-benzoquinone by molecular oxygen in the presence of catalytic amount of copper (II) chloride/amine hydrochloride in alcoholic solvent at ambient temperature.
- Takehira,Shimizu,Watanabe,Orita,Hayakawa
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- A Novel Synthesis of Trimethyl-p-benzoquinone: Copper(II)-hydroxylamine catalysed Oxygenation of 2,3,6-Trimethylphenol with Dioxygen
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2,3,6-Trimethylphenol was efficiently oxygenated to trimethyl-p-benzoquinone with molecular oxygen in the presence of a catalytic amount of copper(II) chloride-hydroxylamine in an alcoholic solvent at ambient temperature.
- Takehira, Katsuomi,Shimizu, Masao,Watanabe, Yoshihito,Orita, Hideo,Hayakawa, Takashi
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- New Co(II) and Cu(II) Phthalocyanine Catalysts Reinforced by Long Alkyl Chains for the Degradation of Organic Pollutants
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Abstract: The need to develop sustainable, low-cost, earth abundant catalyst is becoming paramount for overcoming environmental problems. Toward this goal, new cobalt(II) and copper(II) phthalocyanine complexes used as catalyst for degradation of organic pollutants (such as 2,3-dichlorophenol, 4-methoxyphenol, 4-nitrophenol, 2,3,6-trimethylphenol) with different oxygen source. This catalytic system with these complexes showed high conversion rates for degradation of organic pollutants and could easily be recovered by recycling reactions. Graphical Abstract: [Figure not available: see fulltext.].
- Saka, Ece Tugba,?a?lar, Yasemin
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- Large centimeter-sized macroporous ferritin gels as versatile nanoreactors
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Organized assemblies of bionanoparticles such as ferritin provides templates that can be exploited for nanotechnological applications. Organization of ferritin into well-defined three-dimensional assemblies is challenging and has attracted considerable attention recently. We have synthesized, for the first time, large (centimeter-sized) self-standing macroporous scaffold monoliths from ferritin bionanoparticles, using dynamic templating of surfactant H1 domains. These scaffolds comprise three-dimensionally connected strands of ferritin, organized as a porous gel with porosity ~55 μm. The iron oxide inside the ferritin scaffold can be easily replaced with catalytically active monodisperse zerovalent transition metal nanoparticles using a very simple protocol. Since the ferritin is cross-linked in the scaffold, it is significantly robust with enhanced thermal stability and better tolerance toward several organic solvents in comparison to the native ferritin bionanoparticle. In addition, the scaffold macropores facilitate substrate and reagent transport and hence the monoliths containing active Pd or iron oxide nanoparticles inside apo-ferritin bionanoparticles were used as a recyclable heterogeneous catalyst for the oxidation of 2,3,6-trimethyl phenol to 2,3,6-trimethyl-1,4-benzoquinone (precursor for Vitamin E synthesis) and for Suzuki-Miyaura cross-coupling reaction in both aqueous and organic solvents. The protein shell around the nanoparticles protects them from agglomeration, a phenomenon that otherwise plagues nanoparticles-based catalysis. The presence of macropores allow the ferritin scaffold to act as catalytic monolith for continuous flow reactions having rapid reaction rates, while offering a low pressure drop. Finally, the Pd@apo-ferritin scaffold was immobilized inside a steel cartridge and used for the continuous flow hydrogenation of alkenes to their corresponding alkanes for 15 cycles without any loss of activity.
- Kumari, Sushma,Kulkarni, Amol,Kumaraswamy, Guruswamy,Sen Gupta, Sayam
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- Preparation, characterization of new Co(II) and Cu(II) phthalocyanines and their catalytic performances in aerobic oxidation of substituted phenols
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Substituted phenol pollutants are produced as by products of many industrial processes. Aerobic oxidations for their degradation in the context of effluent treatment or environmental remediation often lack selectivity. In this work Co(II) and Cu(II) phthalocyanines-catalyzed approach is described that converts substituted phenols into less harmfull products. New cobalt(II) and copper(II) phthalocyanine complexes are used as catalyst for degradation of substituted phenols with different oxidants. The oxidation process exhibits remarkable selectivity and conversion owing to the fact that Co(II) and Cu(II) phthalocyanines work with high performance.
- Saka, Ece Tugba
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- The efficient catalytic oxidation of 2,3,6-trimethylphenol with air over composite catalyst to synthesize Vitamin E intermediate
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2,3,5-Trimethylbenzoquinone (TMBQ)is a kind of crucial intermediate in the synthesis of Vitamin E, whose demand is increasing rapidly. The traditional synthesis method of TMBQ needs H2O2 or pure O2 as the oxidant, which is expensive and needs much attention in the production, transportation and storage process. In order to overcome the issues, the green oxidant, air, has been developed in this work to prepare TMBQ for the first time. TMBQ was synthesized from 2,3,6-trimethylphenol (TMP) with the oxidant of air in the solvent of isoamylol catalyzed by composite catalyst of inorganic salts at one atmosphere pressure. The critical reaction parameters, including the ingredient of composite catalyst, reaction time, reaction temperature, stirring speed and the addition of ionic liquids were investigated in order to achieve the optimal reaction condition. TMBQ was obtained with the conversion of 100% and selectivity of 96.7% at 90?°C for 7–8?h at one atmosphere pressure, over the composite catalyst, the aqueous solution of CuCl2, FeCl3 and MgCl2, with the help of ion liquid, 1-sulfobutyl-3-methylimidazole hydrochloride ([Bmim]Cl). Moreover, the catalyst could be recycled more than four times. Air is very cheap, abundant, eco-friendly and safe in production, transportation and storage process. The synthesis of TMBQ from TMP with air as oxidant at one atmosphere pressure has obvious advantages, which will bring new inspiration for the industrial production of TMBQ. Graphic abstract: [Figure not available: see fulltext.].
- Zhang, Tianyong,Song, Yuxin,Yang, Yang,Li, Bin,Jiang, Shuang
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- Highly selective H2O2-based oxidation of alkylphenols to p-benzoquinones over MIL-125 metal-organic frameworks
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The titanium-based metal-organic framework MIL-125 and its amine-functionalized analog, MIL-125-NH2, have been synthesized and characterized by elemental analysis, XRD, SEM, TEM, N2 adsorption measurements, and spectroscopic techniques, including FTIR, Raman, and DR UV/Vis spectroscopy. Catalytic properties of MIL-125 and MIL-125-NH2 were evaluated in the selective oxidation of two representative alkyl-substituted phenols, 2,3,6-trimethylphenol and 2,6-di-tert-butylphenol, with the clean oxidant H2O2. With both MIL-125 and MIL-125-NH 2, the selectivity toward the corresponding p-benzoquinones was 100 %. Samples of MIL-125 with different sizes of crystallites (0.5, 1.5, and 5 μm) demonstrated similar reaction rates, thus indicating the absence of diffusion limitations. The efficiency of the oxidant utilization and stability of the MIL-125 structure increased upon decreasing the amount of water in the reaction mixture. Even if the structural integrity of MIL-125 was destroyed by the reaction medium, the metal-organic framework acted as a precursor for the highly active, selective, and recyclable catalyst. The MIL-125-derived materials were stable toward titanium leaching, behaved as true heterogeneous catalysts, and could easily be recovered by filtration and reused several times without the loss of the catalytic properties. Copyright
- Ivanchikova, Irina D.,Lee, Ji Sun,Maksimchuk, Nataliya V.,Shmakov, Alexander N.,Chesalov, Yurii A.,Ayupov, Artem B.,Hwang, Young Kyu,Jun, Chul-Ho,Chang, Jong-San,Kholdeeva, Oxana A.
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- Effect of combination sequence of precursors on the structural and catalytic properties of Ti-SBA-15
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The combination sequence of Ti and Si precursors (TTIP and TEOS) in the synthesis solution of Ti-incorporated SBA-15 mesoporous silica (shortly termed Ti-SBA-15) was found for the first time to be critical for the distribution of tetrahedrally (Td) coordinated Ti(iv) sites in the resultant Ti-SBA-15. It was found that TTIP pre-assembled with P123 in the synthesis solution for 3 h before the addition of TEOS gave Td-coordinated Ti(iv) sites predominately incorporated near the superficial regions of the framework and were highly accessible to the reactants in catalytic reactions. The Royal Society of Chemistry 2013.
- Kuo, Feng-Ting,Chen, Shih-Yuan,Lin, Tsung-Han,Lee, Jyh-Fu,Cheng, Soofin
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- Highly selective oxidation of alkylphenols to p-benzoquinones with aqueous hydrogen peroxide catalyzed by divanadium-substituted polyoxotungstates
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The catalytic performance of divanadium- and dititanium-substituted γ-Keggin polyoxotungstates, TBA4H[γ-PW10V 2O40] (I, TBA = tetra-n-butylammonium), TBA 4H2[γ-SiW10V2O40] (II), and TBA8[{γ-SiW10Ti2O 36(OH)2}2(μ-O)2] (III) has been assessed in the selective oxidation of industrially important alkylphenols/naphthols with the green oxidant 35% aqueous H2O 2. Phosphotungstate I revealed a superior catalytic performance in terms of activity and selectivity and produced alkylsubstituted p-benzo- and naphthoquinones with good to excellent yields. By applying the optimized reaction conditions, 2,3,5-trimethyl-p-benzoquinone (TMBQ, vitamin E key intermediate) was obtained in a nearly quantitative yield via oxidation of 2,3,6-trimethylphenol (TMP). The efficiency of H2O2 utilization reached 90%. The catalyst retained its structure under turnover conditions and could be recycled and reused. An active peroxo vanadium complex responsible for the oxidation of TMP to TMBQ has been identified using 51V and 31P NMR spectroscopy.
- Ivanchikova, Irina D.,Maksimchuk, Nataliya V.,Maksimovskaya, Raisa I.,Maksimov, Gennadii M.,Kholdeeva, Oxana A.
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- A green catalytic method for selective synthesis of iodophenols via aerobic oxyiodination under organic solvent-free conditions
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A highly efficient catalytic method for aerobic oxyiodination of various phenols catalysed by copper(II) nitrate was achieved under mild conditions using I2as an iodinating reagent, molecular oxygen as an oxidant, and water as a solvent. The catalyst shows not only high activity for phenols with either electron-donating or electron-withdrawing groups, but also a remarkable selectivity for the formation of para-iodo substituted phenols. This study offers a green method for iodination of aromatic phenols with high atom economy.
- Xin, Hongchuan,Hu, Liangning,Yu, Jianqiang,Sun, Wenshou,An, Zengjian
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- METHOD FOR PRODUCING MULTISUBSTITUTED BIPHENYL COMPOUND AND SOLID CATALYST TO BE USED THEREIN
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A method for producing a multisubstituted biphenyl compound is represented by the following formula (2), including a step of coupling a substituted benzene compound represented by the following formula (1) in the presence of a solid catalyst with gold immobilized onto a support.
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Paragraph 0192
(2015/12/23)
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- Highly active and green mesostructured titanosilicate catalysts synthesized for selective synthesis of benzoquinones
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Two-dimensional hexagonal thick-walled mesoporous titanosilicate catalysts synthesized using various amounts of titanium were used for the synthesis of 2,3,5-trimethyl-1,4-benzoquinone (TMBO) by liquid-phase oxidation of 2,3,6-trimethylphenol (TMP-OH). These catalysts were also used for the oxidation of di-/tri-substituted phenols to produce 2,6-disubstituted p-benzoquinones (DSBQs). A promising chemical treatment method, for the preparation of green mesoporous TiSBA-15(6) or Washed TiSBA-15(6), was used for removal of non-framework TiO2 nanoparticle species from the active surface, and the catalytic activity of the recovered mesoporous TiSBA-15(6) catalyst has been evaluated. To confirm the green aspects, recyclability and hot-catalytic filtration experiments were performed. Based on the experimental results, it was found that the green mesoporous TiSBA-15(6) is a highly active, recyclable, and promising heterogeneous catalyst for the selective synthesis of TMBO and DSBQs and produces >99% TMBO selectivity with 100% TMP-OH conversion at 353 K for 60 min and 90-100% DSBQs selectivity with 83-99% phenol conversion at 330 K for 1-5 h.
- Selvaraj
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p. 2674 - 2684
(2014/07/22)
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- Gold-catalyzed oxidation of substituted phenols by hydrogen peroxide
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Gold nanoparticles deposited on inorganic supports are efficient catalysts for the oxidation of various substituted phenols (2,6-di-tert-butyl phenol and 2,3,6-trimethyl phenol) with aqueous hydrogen peroxide. By contrast to more conventional catalysts such as Ti-containing mesoporous silicas, which convert phenols to the corresponding benzoquinones, gold nanoparticles are very selective to biaryl compounds (3,3′,5,5′-tetra-tert-butyl diphenoquinone and 2,2′,3,3′,5,5′-hexamethyl-4,4′- biphenol, respectively). Products yields and selectivities depend on the solvent used, the best results being obtained in methanol with yields >98%. Au offers the possibility to completely change the selectivity in the oxidation of substituted phenols and opens interesting perspectives in the clean synthesis of biaryl compounds for pharmaceutical applications.
- Cheneviere, Yohan,Caps, Valérie,Tuel, Alain
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experimental part
p. 129 - 134
(2011/06/21)
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- Highly selective oxidation of alkylphenols to benzoquinones with hydrogen peroxide over silica-supported titanium catalysts: Titanium cluster site versus titanium single site
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Titanium-silica catalysts have been prepared by supporting titanium(IV) precursors with different nuclearity {mononuclear titanocene dichloride Ti(Cp)2Cl2, dinuclear titanium diethyl tartrate and the tetranuclear titanium peroxo complex (NH4)8[Ti 4(C6H4O7)4(O 2)4].8H2O} onto the surface of silica materials with different textural characteristics. The supported catalysts have been explored as highly active and reusable catalysts for the oxidation of 2,3,6-trimethylphenol (TMP) and 2,6-dimethylphenol (DMP) to 2,3,5-trimethyl-l,4- benzoquinone (TMBQ, vitamin E key intermediate) and 2,6-dimethyl-l,4- benzoquinone (DMBQ), respectively, using aqueous hydrogen peroxide as green oxidant. Catalysts prepared by grafting mononuclear Ti(Cp)2Cl 2 revealed a strong dependence of the product selectivity on the surface concentration of titanium active centers. Mesoporous materials with titanium surface concentration in the range of 0.61.0 Ti/nm2 were identified as optimal catalysts for the transformation of alkylphenols to benzoquinones. Catalysts having 2 produced a mixture of benzoquinones and dimeric by-products. Conversely, when di-/tetranuclear titanium precursors were employed for the catalyst preparation, a diminution of the titanium surface concentration had no impact on the benzoquinone selectivity, which was typically as high as 96-99%. DR-UV spectroscopic studies revealed that the catalysts capable of producing alkylbenzoquinones with nearly quantitative yields possess titanium dimers and/or subnanometer-size clusters homogeneously distributed on a silica surface. On the contrary, catalysts with isolated titanium sites give a considerable amount of dimeric by-products. This is the first example which clearly demonstrates the advantages of titanium cluster-site catalysts over titanium single-site catalysts in hydrogen peroxidebased selective oxidation reaction.
- Kholdeeva, Oxana A.,Ivanchikova, Irina D.,Guidotti, Matteo,Pirovano, Claudio,Ravasio, Nicoletta,Barmatova, Marina V.,Chesalov, Yurii A.
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supporting information; experimental part
p. 1877 - 1889
(2011/03/20)
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- Kinetics and mechanism of the oxidation of alkyl substituted phenols and naphthols with tBuOOH in the presence of supported iron phthalocyanine
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2,3,5-Trimethylbenzoquinone (precursor of vitamin E) and 2-methylnaphthoquinone (vitamin K3) were obtained in good yields by oxidation of 2,3,6-trimethylphenol and 2-methyl-1-naphthol, respectively, with tBuOOH catalyzed by supported
- Zalomaeva, Olga V.,Ivanchikova, Irina D.,Kholdeeva, Oxana A.,Sorokin, Alexander B.
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body text
p. 1031 - 1037
(2010/08/22)
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- BIFUNCTIONAL BIPHENYL AND PROCESS FOR PRODUCING BIFUNCTIONAL PHENYLENE ETHER OLIGOMER COMPOUND USING THE SAME
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A process for producing 2,2′,3,3′,5,5′-hexamethyl-[1,1′-biphenyl]-4,4′-diol, which process comprises, while setting a pH of a reaction liquid containing an alkaline aqueous solution, a surfactant, a copper catalyst and 2,3,6-trimethylphenol during a reaction in the range of from 8 to 14 and controlling the variation range of the pH of the reaction liquid within ±1, oxidatively coupling the 2,3,6-trimethylphenol with an oxygen-containing gas, and a process for producing a bifunctional phenylene ether oligomer compound having a controlled average molecular weight, comprising carrying out oxidation polymerization under a proper oxygen concentration.
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- Selective oxidation of phenols to hydroxybenzaldehydes and benzoquinones with dioxygen catalyzed by polymer-supported copper
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Oxidation of 2,6-disubstituted 4-methylphenols with dioxygen by using a CuCl2-poly(4-methyl-4′-vinyl-2,2′-bipyridine) catalyst gave the corresponding 4-hydroxybenzaldehydes in high yields. The activity of the catalyst and the selectivity of the products significantly depended on the reaction conditions and the composition of the catalyst. When the molar ratio of the bipyridine unit of the polymer ligand to Cu was unity, i.e., N/Cu = 2, the best results were obtained. Moreover, the reaction is likely to be promoted by coordination of the products to the catalyst. Similarly, 2,3,6-trimethylphenol and related compounds were converted to p-benzoquinones selectively with a CuCl2-poly(4-vinylpyridine) catalyst. These polymer-supported catalysts were readily recovered and are reusable without noticeable decrease of their activity.
- Takaki, Ken,Shimasaki, Yohei,Shishido, Tetsuya,Takehira, Katsuomi
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p. 311 - 317
(2007/10/03)
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- Molybdovanadophosphate Heteropolyanion Catalysed Oxidation of 2,3,6-Trimethylphenol by Dioxygen in a Two-phase System
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The oxidation of 2,3,6-trimethylphenol with O2 is catalysed by molybdovanadophosphate heteropolyanions in a two-phase aqueous-organic system to yield 84% trimethyl-p-benzoquinone; the product can be easily isolated from the organic phase, while the aqueous phase, containing the catalyst, can be re-used without loss of activity.
- Kozhevnikov, Ivan V.,Sinnema, Anton,Van Bekkum, Herman
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p. 238 - 239
(2007/10/03)
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- Oxidation of Phenols and Hydroquinones by Dioxygen Catalyzed by Mixed Addenda Heteropolyoxometalate on Active Carbon (NPV6Mo6/C)
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Vanadomolybdophosphate supported on active carbon, NPV6Mo6/C, catalyzed the oxidation and coupling reaction of 2,3,6-trimethylphenol by dioxygen to give trimethyl-p-benzoquinone and 4,4'-dihydroxy-2,2',3,3',5,5'-hexamethylbiphenyl, respectively, depending on the solvent used.Hydroquinones and benzyl alcohol were selectively dehydrogenated by the present system, giving the corresponding p-benzoquinones and benzaldehyde, respectively, in good yields.
- Fujibayashi, Shinya,Nakayama, Kouichi,Nishiyama, Yutaka,Ishii, Yasutaka
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p. 1345 - 1348
(2007/10/02)
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- Choice of Manganese(III) Complexes for the Synthesis of 4,4'-Biphenyldiols and 4,4'-Diphenoquinones
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2,6-Disubstituted phenols are oxidized with tris(2,4-pentanedionato)manganese(III), , in glacial acetic acid to give the corresponding 4,4'-biphenyldiols in high yields, whereas similar reactions using manganase(III) acetate, , instead of quantitatively yield the corresponding 4,4'-diphenoquinones.Cross-coupling reactions of 2,6-di-t-butylphenol and other substituted phenols afford the corresponding cross-coupled 4,4'-biphenyldiols and 4,4'-diphenoquinones together with oxidation products derived from them starting phenols themselves.The advantageous use of and Mn(OAc)3> in the ubiqitous phenol coupling reaction is discussed.
- Nishino, Hiroshi,Nobuyuki, Itoh,Nagashima, Makiko,Kurosawa, Kazu
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p. 620 - 622
(2007/10/02)
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