- Kinetics of Valeric Acid Ketonization and Ketenization in Catalytic Pyrolysis on Nanosized SiO2, γ-Al2O3, CeO2/SiO2, Al2O3/SiO2 and TiO2/SiO2
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Valeric acid is an important renewable platform chemical that can be produced efficiently from lignocellulosic biomass. Upgrading of valeric acid by catalytic pyrolysis has the potential to produce value added biofuels and chemicals on an industrial scale. Understanding the different mechanisms involved in the thermal transformations of valeric acid on the surface of nanometer-sized oxides is important for the development of efficient heterogeneously catalyzed pyrolytic conversion techniques. In this work, the thermal decomposition of valeric acid on the surface of nanoscale SiO2, γ-Al2O3, CeO2/SiO2, Al2O3/SiO2 and TiO2/SiO2 has been investigated by temperature-programmed desorption mass spectrometry (TPD MS). Fourier transform infrared spectroscopy (FTIR) has also been used to investigate the structure of valeric acid complexes on the oxide surfaces. Two main products of pyrolytic conversion were observed to be formed depending on the nano-catalyst used—dibutylketone and propylketene. Mechanisms of ketene and ketone formation from chemisorbed fragments of valeric acid are proposed and the kinetic parameters of the corresponding reactions were calculated. It was found that the activation energy of ketenization decreases in the order SiO2>γ-Al2O3>TiO2/SiO2>Al2O3/SiO2, and the activation energy of ketonization decreases in the order γ-Al2O3>CeO2/SiO2. Nano-oxide CeO2/SiO2 was found to selectively catalyze the ketonization reaction.
- Kulyk, Kostiantyn,Palianytsia, Borys,Alexander, John D.,Azizova, Liana,Borysenko, Mykola,Kartel, Mykola,Larsson, Mats,Kulik, Tetiana
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- Boosting activity of molecular oxygen by pyridinium-based photocatalysts for metal-free alcohol oxidation
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An eco-friendly and economical approach for the photocatalytic oxidation of organic inter-mediates by air under mild conditions is highly desirable in green and sustainable chemistry, where the photogeneration of active oxygen species plays a key role in improving conversion efficiency and selectivity. By using pyridinium derivatives as molecular mediators for electron transfer and energy transfer, the simultaneous activation of O2from air into superoxide radicals and singlet oxygen species can be achieved, and a photoinduced electron transfer catalytic system for the oxidation of alcohols has been developed. Thus, we have successfully simplified the complicated catalytic system into a single molecular catalyst without any additional noble metals and co-catalysts/additives. The current photocatalytic system shows high catalytic efficiency not only for aromatic alcohols but also for aliphatic alcohols that are generally difficult to undergo aerobic oxidation at room temperature under air atmosphere, representing an ideal photocatalytic platform for green and economical organic syntheses.
- Ma, Shuai,Cui, Jing-Wang,Rao, Cai-Hui,Jia, Meng-Ze,Chen, Yun-Rui,Zhang, Jie
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supporting information
p. 1337 - 1343
(2021/02/26)
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- Sulfonium ion-promoted traceless Schmidt reaction of alkyl azides
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Schmidt reaction by sulfonium ions is described. General primary, secondary, and tertiary alkyl azides were converted to the corresponding carbonyl or imine compounds without any trace of the activators. This bond scission reaction through 1,2-migration of C-H and C-C bonds was accessible to the one-pot substitution reaction.
- Ardiansah, Bayu,Kakiuchi, Kiyomi,Morimoto, Tsumoru,Tanimoto, Hiroki,Tomohiro, Takenori
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p. 8738 - 8741
(2021/09/08)
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- Fast Addition of s-Block Organometallic Reagents to CO2-Derived Cyclic Carbonates at Room Temperature, Under Air, and in 2-Methyltetrahydrofuran
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Fast addition of highly polar organometallic reagents (RMgX/RLi) to cyclic carbonates (derived from CO2 as a sustainable C1 synthon) has been studied in 2-methyltetrahydrofuran as a green reaction medium or in the absence of external volatile organic solvents, at room temperature, and in the presence of air/moisture. These reaction conditions are generally forbidden with these highly reactive main-group organometallic compounds. The correct stoichiometry and nature of the polar organometallic alkylating or arylating reagent allows straightforward synthesis of: highly substituted tertiary alcohols, β-hydroxy esters, or symmetric ketones, working always under air and at room temperature. Finally, an unprecedented one-pot/two-step hybrid protocol is developed through combination of an Al-catalyzed cycloaddition of CO2 and propylene oxide with the concomitant fast addition of RLi reagents to the in situ and transiently formed cyclic carbonate, thus allowing indirect conversion of CO2 into the desired highly substituted tertiary alcohols without need for isolation or purification of any reaction intermediates.
- Elorriaga, David,de la Cruz-Martínez, Felipe,Rodríguez-álvarez, María Jesús,Lara-Sánchez, Agustín,Castro-Osma, José Antonio,García-álvarez, Joaquín
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p. 2084 - 2092
(2021/04/02)
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- One-pot direct conversion of levulinic acid into high-yield valeric acid over a highly stable bimetallic Nb-Cu/Zr-doped porous silica catalyst
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The direct conversion of levulinic acid (LA) to valeric biofuel is highly promising for the development of biorefineries. Herein, LA is converted into valeric acid (VA) via one-pot direct cascade conversion over non-noble metal-based Nb-doped Cu on Zr-doped porous silica (Nb-Cu/ZPS). Under mild reaction conditions (150 °C and 3.0 MPa H2 for 4 h), LA was completely converted into VA in high yield (99.8%) in aqueous medium with a high turnover frequency of 0.038 h-1. The Lewis acid sites of ZPS enhanced the adsorption of LA on the catalyst surface, and both the Lewis and Br?nsted acidity associated with Nb2O5 and the metallic Cu0 sites promoted catalysis of the cascade hydrogenation, ring cyclization, ring-opening, and hydrogenation reactions to produce VA from LA. The bimetallic Nb-Cu/ZPS catalyst was also effective for the conversion of VA into various valeric esters in C1-C5 alcohol media. The presence of Nb2O5 effectively suppressed metal leaching and coke formation, which are serious issues in the liquid-phase conversion of highly acidic LA during the reaction. The catalyst could be used for up to five consecutive cycles with marginal loss of activity, even without catalyst re-activation.
- Karanwal, Neha,Verma, Deepak,Butolia, Paresh,Kim, Seung Min,Kim, Jaehoon
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supporting information
p. 766 - 787
(2020/02/25)
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- Oxidation of secondary alcohols using solid-supported hypervalent iodine catalysts
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It is shown how secondary alcohols are oxidized to provide the corresponding ketones by use of Oxone and solid-supported hypervalent iodine catalysts. Under experimentally simple conditions with acetonitrile at elevated temperatures, excellent conversions were achieved with low catalyst loadings (0.2-5 mol%) when employing the conjugates 5 and 6 derived from IBX and IBS. The catalysts are broadly applicable to a range of alcohol substrates. Of primary importance with respect to sustainability issues, the metal-free catalysts are easily removed from the reaction mixture through filtration, and they can be re-used in oxidation processes for multiple times, without loss of catalytic activity.
- Ballaschk, Frederic,Kirsch, Stefan F.
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supporting information
p. 5896 - 5903
(2019/11/11)
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- Nickel-catalyzed reductive defunctionalization of esters in the absence of an external reductant: Activation of C-O bonds
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The nickel-catalyzed reductive cleavage of esters in the absence of an external reductant, which involves the cleavage of an inert acyl C-O bond in O-Alkyl esters is reported. Various groups, such as N-containing heterocycles, esters, amides, and even arene rings can function as a directing group.
- Iyori, Yasuaki,Takahashi, Kenjiro,Yamazaki, Ken,Ano, Yusuke,Chatani, Naoto
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p. 13610 - 13613
(2019/11/14)
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- Preparation method of 3,6,6-trimethyl-2,4-cycloheptadienone
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The invention discloses a preparation method of 3,6,6-trimethyl-2,4-cycloheptadienone. The preparation method comprises the following steps: reacting 3-carene with O2 at 35 DEG C for 24 hours under the catalysis of CrO3-Al2O3 so as to generate a product I with a main component of 5-carone, wherein the conversion rate of 3-carene is about 81.3%, and the selectivity of 5-carone is 60.1%; reacting byvirtue of the product I at a pressure of 0-1kPa and temperature of 120 DEG C for 4 hours so as to convert the product I into a product II with a main component of 3,6,6-trimethyl-2,4-cycloheptadienone, wherein the conversion rate of 5-carone is about 100%, and the selectivity of 3,6,6-trimethyl-2,4-cycloheptadienone is 98.7%; and carrying out reduced pressure distillation on the product II, so asto obtain 3,6,6-trimethyl-2,4-cycloheptadienone, wherein the yield is more than 75%, and the purity is more than 95%.
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Paragraph 0025-0030; 0035-0038
(2019/03/08)
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- Iminyl Radical-Triggered Intermolecular Distal C(sp3)-H Heteroarylation via 1,5-Hydrogen-Atom Transfer (HAT) Cascade
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An efficient iron-catalyzed intermolecular remote C(sp3)-H heteroarylation of alkyl ketones has been developed via an iminyl radical-triggered 1,5-hydrogen-atom transfer (HAT) cascade. This protocol was amenable to a wide variety of alkyl ketones and heteroaryls, thus providing a straightforward method for the late-stage functionalization of alkylketones and heteroaryls.
- Gu, Yu-Rui,Duan, Xin-Hua,Chen, Li,Ma, Zhi-Yong,Gao, Pin,Guo, Li-Na
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supporting information
p. 917 - 920
(2019/02/14)
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- Metal-Free catalyst for visible-light-induced oxidation of unactivated alcohols using Air/Oxygen as an oxidant
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9-Fluorenone acts as a metal-free and additive-free photocatalyst for the selective oxidation of primary and secondary alcohols under visible light. With this photocatalyst, a plethora of alcohols such as aliphatic, heteroaromatic, aromatic, and alicyclic compounds has been converted to the corresponding carbonyl compounds using air/oxygen as an oxidant. In addition to these, several steroids have been oxidized to the corresponding carbonyl compounds. Detailed mechanistic studies have also been achieved to determine the role of the oxidant and the photocatalyst for this oxidation.
- Schilling, Waldemar,Riemer, Daniel,Zhang, Yu,Hatami, Nareh,Das, Shoubhik
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p. 5425 - 5430
(2018/05/15)
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- Catalytic oxidation of alcohols with novel non-heme N4-tetradentate manganese(ii) complexes
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We report the preparation and characterisation of a series of novel non-heme N4-tetradentate Mn(OTf)2 complexes of the type, [(L)MnOTf2], where L = R,R and S,S enantiomers of BPMCN, its 6-methyl and 6-bromo derivatives as well as the novel ligand BMIMCN (BPMCN = N,N′-dimethyl-N,N′-bis(2-pyridylmethyl)-(R,R/S,S)-1,2-diaminocyclohexane, BMIMCN = N,N′-dimethyl-N,N′-bis(1-methyl-2-imidazolemethyl)-(R,R/S,S)-1,2-diaminocyclohexane). Solid state structural analysis of the BMIMCN-ligated Mn-triflate complexes (R,R-C4 and S,S-C4) revealed opposite helicity but identical metal site accessibility. This feature was exploited in the catalytic oxidation of primary and secondary alcohols, with hydrogen peroxide as oxidant and acetic acid as co-catalyst. Complexes R,R-C4 and S,S-C4 displayed the highest activity in benzyl alcohol oxidation, attributed to the electron-donating property of the BMIMCN ligand. Complex S,S-C4, displayed high activity for a variety of primary alcohol substrates, but the reaction suffered from reduced selectivity and side-reactions due to the presence of acetic acid. In contrast, secondary alcohol substrates could be oxidised to the corresponding ketone products in excellent isolated yields under mild reaction conditions and short reaction times.
- Vermaak, Vincent,Young, Desmond A.,Swarts, Andrew J.
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supporting information
p. 16534 - 16542
(2018/12/05)
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- Reactions of organoboranes with carbanions bearing three potential leaving groups: unusual processes, products and mechanisms
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Known reagents that transfer three alkyl groups of a trialkylborane intramolecularly to a single carbon atom lack features to influence stereochemistry. We have investigated four reagents of type LiCCl2X, where X might be amenable to variation. All behaved differently. With X=OR (R=cyclohexyl, menthyl), the reagent decomposed, leading to only low yields of triple migration products. With X=S(O)Ph, a single migration occurred, followed by isomerisation to boron enolate-like species that hydrolysed to α-chloroalkyl phenyl sulfoxides or reacted with aldehydes to aldol-like products. With X=SO2Ph, the major product was the corresponding α,α-dichloroalkyl phenyl sulfone, apparently formed through a redox reaction. With X=S(O)(NMe)Ph, products of three intramolecular alkyl migrations were obtained with unhindered trialkylboranes. Attempts have been made to gain understanding of the sulfoxide process by investigating proportions of aldol-like products, using X-ray crystallography and ab initio calculations.
- Saleh, Basil A.,Smith, Keith,Elliott, Mark C.,Jones, D. Heulyn,Kariuki, Benson M.,El Hiti, Gamal A.
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p. 6914 - 6928
(2016/10/14)
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- Dehydrocyclization of C6 Hydrocarbon with and Without Oxygen Containing Substituent over Pt/(Na)-Al2O3 Catalyst
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The presence of hydroxyl or keto functional group affects both activity and selectivity for dehydrocyclization of C6 hydrocarbon over Pt/(Na)-Al2O3 catalyst. Under similar reaction conditions, n-hexane produces benzene as the primary product (>40 %), whereas dehydration is a major reaction pathway for 2-hexanol and yields mainly hexenes (>70 %). However, 2-hexanone was found to be involved in a variety of reactions over Pt/(Na)-Al2O3 catalyst and produces lower hydrocarbons (C2-C5), 5-dodecanone, 2- And 5-nonanones, and 2-acetyl-3-propyl-2-cyclohexen-1-one. The presence of hydroxyl (-OH) or keto group (=C=O) at the C-2 position alters the interaction of C6 hydrocarbon with the catalyst surface which eventually controls the overall product selectivity.
- Gnanamani, Muthu Kumaran,Shafer, Wilson D.,Keogh, Robert A.,Davis, Burtron H.
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p. 424 - 432
(2016/02/23)
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- Photoinduced Oxidation of Secondary Alcohols Using 4-Benzoylpyridine as an Oxidant
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Photoinduced oxidation of secondary alcohols to ketones was achieved by utilizing an equimolar amount of 4-benzoylpyridine as an oxidant. This transformation proceeds at ambient temperature and exhibits high compatibility with polar functionalities including benzoyl, silyl, and methoxymethyl alcohol protecting groups as well as tosyloxy, bromo, sulfonyl, carbamate, ester, and carboxylic acid units. The present oxidation is solely promoted by the action of organic molecules without the aid of metallic reagents. (Chemical Equation Presented).
- Kamijo, Shin,Tao, Keisuke,Takao, Go,Tonoda, Hiroshi,Murafuji, Toshihiro
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supporting information
p. 3326 - 3329
(2015/07/15)
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- Reactivity of mixed organozinc and mixed organocopper reagents: 12. Three component reaction of mixed (n-alkyl)(diaryl)zincates, chloroformates and phosphines for the synthesis of esters
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The reaction of mixed n-butyldiphenylzincate, n-BuPh2ZnMgBr with ethyl chloroformate, ClCOOEt in the presence n-Bu3P in THF takes place with quantitative yield and phenyl group transfer to give PhCOOEt. Ethoxycarbonylation of n-BuPh2ZnMgBr is preferable to the reaction of PhMgBr forming ester and triphenylcarbinol and also to the reaction of triphenylzincate, Ph3ZnMgBr for atom economy. Group selectivity in the phosphine catalyzed C-COOR coupling of n-BuPh2ZnMgBr and n-Bu2PhZnMgBr can be controlled by changing reaction parameters. n-Bu3P catalyzed reaction of n-BuPh2ZnMgBr with ClCOOEt takes place with phenyl selectivity whereas reaction of n-Bu2PhZnMgBr with ClCOOPh results in n-butyl transfer. Catalysis by Ph3P increases n-butyl group:phenyl group transfer ratio in the ethoxycarbonylation of both zincates. Selective transfer of aryl groups in n-Bu3P catalyzed reaction of n-butyl(aryl)2ZnMgBr reagents with ClCOOEt in THF provides a new procedure for the organometallic synthesis of arenecarboxylic acid ethyl esters at room temperature.
- ?zkan, Duygu,Erdik, Ender
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- Conversion of levulinic acid derived valeric acid into a liquid transportation fuel of the kerosene type
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In the transformation of lignocellulosic biomass into fuels and chemicals carboncarbon bond formations and rising hydrophobicity are highly desired. The ketonic decarboxylation fits these requirements perfectly as it converts carboxylic acids into ketones forming one carboncarbon bond and eliminates three oxygen atoms as carbon dioxide and water. This reaction is used, in a cascade process, together with a hydrogenation and dehydration catalyst to obtain hydrocarbons in the kerosene range from hexose-derived valeric acid. It is shown that zirconium oxide is a very selective and stable catalyst for this process and when combined with platinum supported on alumina, the oxygen content was reduced to almost zero. Furthermore, it is demonstrated that alumina is superior to active carbon, silica, or zirconium oxide as support for the hydrogenation/dehydration/hydrogenation sequence and a palladium-based catalyst deactivated more rapidly than the platinum catalyst. Hence, under optimized reaction conditions valeric acid is converted into n-nonane with 80% selectivity (together with a 10% of C10-C15 hydrocarbons) in the organic liquid phase upto a 100:1 feed to catalyst ratio [w/w]. The oxygen free hydrocarbon product mixture (85% yield) meets well with the boiling point range of kerosene as evidenced by a simulated distillation. In the gas phase, butane was detected together with mainly carbon dioxide.
- Corma, Avelino,Oliver-Tomas, Borja,Renz, Michael,Simakova, Irina L.
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p. 116 - 122
(2014/06/09)
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- Selective oxidation of alcohols with alkali metal bromides as bromide catalysts: Experimental study of the reaction mechanism
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A bromide-catalyzed oxidation of alcohols was developed which proceeded in the presence of an alkali metal bromide and an oxidant under mild conditions. The reaction involved an organic-molecule-free oxidation using KBr and Oxone and a Br?nsted acid assisted oxidation using KBr and aqueous H 2O2 solution to provide a broad range of carbonyl compounds in high yields. Moreover, the bromide-catalyzed oxidation of primary alcohols enabled the divergent synthesis of carboxylic acids and aldehydes under both reaction conditions in the presence of TEMPO. A possible catalytic mechanism was suggested on the basis of various mechanistic studies.
- Moriyama, Katsuhiko,Takemura, Misato,Togo, Hideo
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p. 6094 - 6104
(2014/07/21)
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- Efficient and eco-compatible transition metal-free Oppenauer-type oxidation of alcohols
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Catalytic amounts of cheap, non-toxic, easy-to-handle and non-sensitive sodium tert-butoxide are able to promote the dehydrogenative oxidation of a wide array of secondary alcohols using inexpensive benzophenone as the H-acceptor. The corresponding ketones, highly important intermediates and targets throughout life and material sciences, are very selectively obtained under mild conditions.
- Ballester, Jorge,Caminade, Anne-Marie,Majoral, Jean-Pierre,Taillefer, Marc,Ouali, Armelle
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- Kinetics and mechanism of oxidation of aliphatic secondary alcohols by benzyltrimethylammonium chlorobromate
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Oxidation of several secondary alcohols by benzyltrimethylammonium chlorobromate (BTMACB) in aqueous acetic acid leads to the formation of corresponding ketones. The reaction is first order with respect to BTMACB and the alcohols. The reaction failed to induce the polymerization of acrylonitrile. There is no effect of tetrabutylammonium chloride on the reaction rate. The proposed reactive oxidizing species is chlorobromate ion. The oxidation of benzhydrol-α-d (PhCDOHPh) exhibited a substantial primary kinetic isotope effect (kH/kD = 5.61 at 298 K). The effect of solvent composition indicated that the rate increases with an increase in the polarity of the solvent. The reaction is susceptible to both the polar and steric effects of the substituents. A mechanism involving transfer of a hydride ion in the ratedetermining step has been proposed.
- Sharma, Pradeep K.
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p. 2702 - 2706
(2014/06/09)
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- Oxidative debenzylation of N-benzyl amides and O-benzyl ethers using alkali metal bromide
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The oxidative debenzylation of N-benzyl amides and O-benzyl ethers was promoted with high efficiency by a bromo radical formed through the oxidation of bromide from alkali metal bromide under mild conditions. This reaction provided the corresponding amides from N-benzyl amides and carbonyl compounds from O-benzyl ethers in high yields.
- Moriyama, Katsuhiko,Nakamura, Yu,Togo, Hideo
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supporting information
p. 3812 - 3815
(2014/08/05)
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- Chemoselective oxidation of secondary alcohols using a ruthenium phenylindenyl complex
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A straightforward catalytic alcohol oxidation procedure using the recently reported complex [RuCl(PPh3)2(3-phenylindenyl)] (1) with KHMDS as cocatalyst, in acetone as the oxidant, is reported. Complex 1 shows remarkable chemoselectivity in oxidizing secondary alcohols to ketones.
- Manzini, Simone,Urbina-Blanco, Cesar A.,Nolan, Steven P.
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p. 660 - 664
(2013/03/14)
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- Manganese-catalyzed selective oxidation of aliphatic C-H groups and secondary alcohols to ketones with hydrogen peroxide
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An efficient and simple method for selective oxidation of secondary alcohols and oxidation of alkanes to ketones is reported. An in situ prepared catalyst is employed based on manganese(II) salts, pyridine-2-carboxylic acid, and butanedione, which provides good-to-excellent conversions and yields with high turnover numbers (up to 10 000) with H2O2 as oxidant at ambient temperatures. In substrates bearing multiple alcohol groups, secondary alcohols are converted to ketones selectively and, in general, benzyl C-H oxidation proceeds in preference to aliphatic C-H oxidation. Manganeasy! MnII, picolinic acid, and butanedione make a smart mix for oxidation of secondary alcohols and alkanes and especially benzylic groups to ketones at room temperature with near stoichiometric amounts of hydrogen peroxide, low catalyst loadings, and high turn-over numbers. Copyright
- Dong, Jia Jia,Unjaroen, Duenpen,Mecozzi, Francesco,Harvey, Emma C.,Saisaha, Pattama,Pijper, Dirk,De Boer, Johannes W.,Alsters, Paul,Feringa, Ben L.,Browne, Wesley R.
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p. 1774 - 1778
(2013/10/21)
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- Acceptor-free dehydrogenation of secondary alcohols by heterogeneous cooperative catalysis between Ni nanoparticles and acid-base sites of alumina supports
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Nickel-nanoparticle-loaded θ-Al2O3 (Ni/θ-Al2O3), prepared by H2-reduction of NiO/θ-Al2O3, acts as an effective and reusable heterogeneous catalyst for acceptor-free dehydrogenation of alcohols in a liquid phase. Among various supports, amphoteric supports (such as θ-Al 2O3), having both acidic and basic sites, gave higher activity than acidic or basic supports. Among Ni/θ-Al2O 3 catalysts with different Ni particle sizes, turnover frequency (TOF) per surface Ni increases with decreasing Ni particle size. These results suggest that low-coordinated Ni0 sites and metal/support interfaces play important roles in the catalytic cycle. The reaction mechanism is investigated by in situ IR study combined with kinetic analysis (kinetic isotope effect), and the following mechanism is proposed: (1) reaction of an alcohol with Lewis acid (Alδ+)-base (AlOδ-) pair site of alumina yields an alkoxide on the Alδ+ site and a proton on the AlOδ- site, (2) CH dissociation of the alkoxide by Ni 0 site to form NiH and a ketone, and (3) protolysis of NiH by a neighboring proton to release H2 gas. The proposed mechanism provides fundamental reasons for the higher activity of Ni on the acid-base bifunctional support (Al2O3) than on basic and acidic ones.
- Shimizu, Ken-Ichi,Kon, Kenichi,Shimura, Katsuya,Hakim, Siddiki S.M.A.
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p. 242 - 250
(2013/04/10)
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- Selective catalytic oxidation of alcohols, aldehydes, alkanes and alkenes employing manganese catalysts and hydrogen peroxide
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The manganese-containing catalytic system [MnIV,IV 2O3(tmtacn)2]2+ (1)/carboxylic acid (where tmtacn=N,N′,N′′-trimethyl-1,4,7-triazacyclononane), initially identified for the cis-dihydroxylation and epoxidation of alkenes, is applied for a wide range of oxidative transformations, including oxidation of alkanes, alcohols and aldehydes employing H2O2 as oxidant. The substrate classes examined include primary and secondary aliphatic and aromatic alcohols, aldehydes, and alkenes. The emphasis is not primarily on identifying optimum conditions for each individual substrate, but understanding the various factors that affect the reactivity of the Mn-tmtacn catalytic system and to explore which functional groups are oxidised preferentially. This catalytic system, of which the reactivity can be tuned by variation of the carboxylato ligands of the in situ formed [MnIII,III 2(O)(RCO2)2(tmtacn)2]2+ dimers, employs H2O2 in a highly atom efficient manner. In addition, several substrates containing more than one oxidation sensitive group could be oxidised selectively, in certain cases even in the absence of protecting groups. Copyright
- Saisaha, Pattama,Buettner, Lea,Van Der Meer, Margarethe,Hage, Ronald,Feringa, Ben L.,Browne, Wesley R.,De Boer, Johannes W.
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supporting information
p. 2591 - 2603
(2013/10/21)
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- Ketonic decarboxylation reaction mechanism: A combined experimental and DFT study
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The ketonic decarboxylation of carboxylic acids has been carried out experimentally and studied theoretically by DFT calculations. In the experiments, monoclinic zirconia was identified as a good catalyst, giving high activity and high selectivity when compared with other potential catalysts, such as silica, alumina, or ceria. It was also shown that it could be used for a wide range of substrates, namely, for carboxylic acids with two to eighteen carbon atoms. The reaction mechanism for the ketonic decarboxylation of acetic acid over monoclinic zirconia was investigated by using a periodic DFT slab model. A reaction pathway with the formation of a β-keto acid intermediate was considered, as well as a concerted mechanism, involving simultaneous carbon-carbon bond formation and carbon dioxide elimination. DFT results showed that the mechanism with the β-keto acid was the kinetically favored one and this was further supported by an experiment employing a mixture of isomeric (linear and branched) pentanoic acids. This way or that? Monoclinic zirconia has great potential as a catalyst for ketonic decarboxylation of carboxylic acids (see picture). A combined experimental and DFT study shows a route involving a β-keto acid intermediate as the kinetically preferred reaction pathway. Copyright
- Pulido, Angeles,Oliver-Tomas, Borja,Renz, Michael,Boronat, Mercedes,Corma, Avelino
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p. 141 - 151
(2013/03/14)
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- An effective and catalytic oxidation using recyclable fluorous IBX
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Oxidation of alcohols in the presence of a catalytic amount of fluorous IBX and Oxone as a co-oxidant resulted in the corresponding carbonyl compounds in good to high yields. The fluorous IBX is readily recovered as insoluble fluorous IBA from the reaction mixture by simple filtration, and can be reused without significant loss of the catalytic activity.
- Miura, Tsuyoshi,Nakashima, Kosuke,Tada, Norihiro,Itoh, Akichika
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supporting information; experimental part
p. 1875 - 1877
(2011/03/22)
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- Catalytic oxidative cleavage of olefins promoted by osmium tetroxide and hydrogen peroxide
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Hydrogen peroxide was employed as the terminal oxidant in the osmium tetroxide mediated oxidative cleavage of olefins, producing the corresponding aldehyde and ketone products. Aryl olefins are cleaved in good to excellent yield regardless of arene electronics. Alkyl olefins cleave in moderate to good yield for di- and tri-substituted alkenes. The Royal Society of Chemistry 2011.
- Hart, Stewart R.,Whitehead, Daniel C.,Travis, Benjamin R.,Borhan, Babak
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experimental part
p. 4741 - 4744
(2011/08/06)
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- Novel electrochemical deoxygenation reaction using diphenylphosphinates
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The electrochemical reduction of diphenylphosphinate esters leads smoothly and in high yields to the corresponding deoxygenated products. In comparison with the previously developed methodologies, the electrolysis could be performed at lower temperature and with a higher current density, resulting in a shorter reaction time.
- Lam, Kevin,Marko, Istvan E.
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p. 406 - 409
(2011/04/18)
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- Catalytic upgrading of levulinic acid to 5-nonanone
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Aqueous solutions of levulinic acid can be catalytically processed, through the intermediate formation of γ-valerolactone (GVL), to an organic liquid stream that spontaneously separates from water, and is enriched in pentanoic acid and 5-nonanone. This organic layer can serve as a source of chemicals or can be upgraded to hydrocarbon fuels.
- Serrano-Ruiz, Juan Carlos,Wang, Dong,Dumesic, James A.
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scheme or table
p. 574 - 577
(2010/08/22)
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- Oxidation of secondary alkanols with the system cerium ammonium nitrate-lithium bromide into ketones, α-bromo ketones, and α,α -dibromo ketones
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Oxidation of secondary alkanols with the system Ce(NH4) 2(NO3)6-LiBr in aqueous acetonitrile gave ketones, α-bromo ketones, or α,α-dibromo ketones. The selectivity of the reaction under standard conditions depends only on the molar ratio of the reagents (alkanol : CeIV : LiBr).
- Nikishin,Sokova,Kapustina
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experimental part
p. 391 - 395
(2011/02/17)
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- Oxidation of primary and secondary alkanols with the CeIII-LiBr- H2O2 system
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Action of a novel oxidation system, Ce(NO3)3? 6H2O (cat.)-LiBr (cat.)-H2O2 (stoichiometric oxidant) on primary aliphatic C6-C9 alcohols gives selectively esters, whereas secondary aliphatic C5-C9 alcohols are converted into ketones. Selectivity of these transformations is provided by slow addition of H2O2 to the other reactants.
- Kapustina,Sokova,Nikishin
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experimental part
p. 1284 - 1288
(2011/02/23)
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- Catalytic Conversion of Cellulose to Liquid Hydrocarbon Fuels by Progressive Removal of Oxygen to Facilitate Separation Processes and Achieve High Selectivities
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Described is a method to make liquid chemicals, such as functional intermediates, solvents, and liquid fuels from biomass-derived cellulose. The method is cascading; the product stream from an upstream reaction can be used as the feedstock in the next downstream reaction. The method includes the steps of deconstructing cellulose to yield a product mixture comprising levulinic acid and formic acid, converting the levulinic acid to γ-valerolactone, and converting the γ-valerolactone to pentanoic acid. Alternatively, the γ-valerolactone can be converted to a mixture of n-butenes. The pentanoic acid so formed can be further reacted to yield a host of valuable products. For example, the pentanoic acid can be decarboxylated yield 1-butene or ketonized to yield 5-nonanone. The 5-nonanone can be hydrodeoxygenated to yield nonane, or 5-nonanone can be reduced to yield 5-nonanol. The 5-nonanol can be dehydrated to yield nonene, which can be dimerized to yield a mixture of C9 and C18 olefins, which can be hydrogenated to yield a mixture of alkanes. Alternatively, the nonene may be isomerized to yield a mixture of branched olefins, which can be hydrogenated to yield a mixture of branched alkanes. The mixture of n-butenes formed from γ-valerolactone can also be subjected to isomerization and oligomerization to yield olefins in the gasoline, jet and Diesel fuel ranges.
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Page/Page column 9-10
(2010/12/31)
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- METHOD FOR PRODUCING CARBONYL COMPOUND AN PRO-OXIDANT USED FOR PRODUCTION OF CARBONYL COMPOUND
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The invention provides a process for the preparation of a carbonyl compound in high efficiency by oxidizing an alcohol. The process for the preparation of a carbonyl compound of the present invention includes a step of oxidizing an alcohol in the presence of a compound of the formula (I) or a derivative or a salt thereof, and an oxidant, wherein R1 and R2 independently represent hydrogen, a halogen, a nitro or acidic group, or an alkyl or alkoxy group, each of which optionally has a substituent, or R1 and R2 combine the two carbon atoms to which they are boned to form an aromatic ring.
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Page/Page column 11; 14
(2009/08/16)
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- 2-iodoxybenzenesulfonic acid as an extremely active catalyst for the selective oxidation of alcohols to aldehydes, ketones, carboxylic acids, and enones with oxone
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Electron-donating group-substituted 2-iodoxybenzoic acids (IBXs) such as5-Me-IBX (1g), 5-MeO-IBX (1h), and 4,5-Me2-IBX were superior to IBX 1a as catalysts for the oxidation of alcohols with Oxone (a trad emark of DuPont) under nonaqueous conditions, although Oxone was almost insoluble in most organic solvents. The catalytic oxidation proceeded more rapidly and cleanly in nitromethane. Furthermore, 2-iodoxybenzenesulfonic acid (IBS, 6a) was much more active than modified IBXs. Thus, we established a highly efficient and selective method for the oxidation of primary and secondary alcohols to carbonyl compounds such as aldehydes, carboxylic acids, and ketones with Oxone in nonaqueous nitromethane, acetonitrile, or ethyl acetate in the presence of 0.05-5molpercentof 6a, which was generated in situ from 2-iodobenzenesulfonic acid (7a) or its sodium salt. Cycloalkanones could be further oxidized to α,β- cycloalkenones or lactones by controlling the amounts of Oxone under the same conditions as above. When Oxone was used under nonaqueous conditions, Oxone wastes could be removed by simple filtration. Based on theoretical calculations, we considered that the relatively ionic character of the intramolecular hypervalent iodine-OSO2 bond of IBS might lower the twisting barrier of the alkoxyperiodinane intermediate 16.
- Uyanik, Muhammet,Akakura, Matsujiro,Ishihara, Kazuaki
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supporting information; experimental part
p. 251 - 262
(2009/06/28)
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- Organic electrosynthesis using toluates as simple and versatile radical precursors
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The electrolysis of toluate esters leads smoothly to the formation of the radical of the alkyl fragment. This property has been used to develop a new electrochemical deoxygenation reaction. The Royal Society of Chemistry.
- Lam, Kevin,Marko, Istvan E.
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experimental part
p. 95 - 97
(2009/03/11)
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- Nickel-catalyzed cross-coupling of unactivated alkyl halides and tosylate carrying a functional group with alkyl and phenyl Grignard reagents
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By the use of catalytic amounts of a nickel salt and a 1,3-butadiene, primary and secondary alkyl Grignard reagents undergo cross-coupling with alkyl bromides, iodide, and tosylate carrying a functional group such as amide, ester, and ketone at 0 °C in THF. The present procedure provides a simple, convenient, and practical method for construction of carbon chains in the presence of various functional groups. PhMgBr also gave the corresponding coupling product in a moderate yield.
- Singh, Surya Prakash,Terao, Jun,Kambe, Nobuaki
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experimental part
p. 5644 - 5646
(2011/02/25)
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- DEAD-(cat)ZnBr2 an efficient system for the oxidation of alcohols to carbonyl compounds
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The combination of diethyl azodicarboxylate (DEAD) and a catalytic amount of ZnBr2 is an efficient system for the dehydrogenation of alcohols to the corresponding carbonyl compounds. The scope and limitations of this process have been studied.
- Cao, Hai Thuong,Grée, René
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experimental part
p. 1493 - 1494
(2009/06/18)
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- Catalytic synthesis of oxygenate from alcohol
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The present invention discloses a method for catalytic synthesis of oxygenate from alcohol. At first, a feeding material comprising at least one alcohol is provided. Next, a copper-containing catalyst is provided and the catalyst further comprises at least one metal element selected from the group consisting of the following: zinc, magnesium, and aluminum elements. Following that, a catalytic reaction of the feeding material over the copper-containing catalyst is carried out to synthesize at least one oxygenate.
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Page/Page column 4-8
(2008/06/13)
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- Kinetics and mechanism of oxidation of secondary alcohols by benzyltriethylammonium chlorochromate
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Oxidation of several aliphatic secondary alcohols by benzyltriethylammonium chlorochromate in dimethylsulfoxide leads to the formation of corresponding ketones. The reaction is first order each in benzyltriethylammonium chlorochromate and the alcohols. The reaction is catalysed by hydrogen ions. Hydrogen-ion dependence has the form: kobs = a + b [H+]. The oxidation of benzhydrol-α-d exhibits a substantial primary kinetic isotope effect (kH/kD = 6.12 at 288 K). Oxidation of 2-propanol has been studied in nineteen different organic solvents. The solvent effect has been analysed using Taft's and Swain's multiparametric equations. The reaction has been subjected to both polar and steric effects of the substituents. A mechanism involving transfer of hydride ion from alcohol to the oxidant via a chromate ester is also proposed.
- Kaur, Ravdeep,Soni, Neelam,Sharma, Vinita
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p. 2441 - 2445
(2007/10/03)
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- 'Reductive ozonolysis' via a new fragmentation of carbonyl oxides
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This account describes the development of methodologies for 'reductive' ozonolysis, the direct ozonolytic conversion of alkenes into carbonyl groups without the intermediacy of 1,2,4-trioxolanes (ozonides). Ozonolysis of alkenes in the presence of DMSO produces a mixture of aldehyde and ozonide. The combination of DMSO and Et3N results in improved yields of carbonyls but still leaves unacceptable levels of residual ozonides; similar results are obtained using secondary or tertiary amines in the absence of DMSO. The influence of amines is believed to result from conversion to the corresponding N-oxides; ozonolysis in the presence of amine N-oxides efficiently suppresses ozonide formation, generating high yields of aldehydes. The reactions with amine oxides are hypothesized to involve an unprecedented trapping of carbonyl oxides to generate a zwitterionic adduct, which fragments to produce the desired carbonyl group, an amine, and 1O2.
- Schwartz, Chris,Raible, Joseph,Mott, Kyle,Dussault, Patrick H.
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p. 10747 - 10752
(2007/10/03)
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- A new efficient deprotection of azines, hydrazones and oximes. An excellent route for exchanging oxygen isotopes in carbonyls
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Carbonyls, protected as azines or other C=N derivatives can be deprotected by HOF·CH3CN in seconds to the corresponding ketone or aldehyde in very good yields. This reaction also offers a very efficient route for replacing the oxygen atom of most carbonyls with any other oxygen isotope, for example, [18]O.
- Carmeli, Mira,Rozen, Shlomo
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p. 763 - 766
(2007/10/03)
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- Catalytic ketonisation over oxide catalysts. Part XI*. Cross-ketonisation of esters of aliphatic and aromatic acids
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The cross-ketonisation of a mixture of ethyl acetate and ethyl benzoate under flow conditions has been studied over 20wt%MO2/Al 2O3 (M = Mn, Ce or Zr) catalysts, at 673-723 K. High conversions of aromatic ester up to 98% and moderate yields of acetophenone (2/Al2O3 catalyst was the least selective. In its presence, the yield of styrene (34%) exceeded that of acetophenone (31%). Unexpectedly, pure Al2O3 support exhibited the highest selectivity and moderate activity, at 723 K the yield as high as 51% of acetophenone was noted. The transformations of mixtures of various ethyl alkanoates with ethyl benzoate over alumina have been studied. In the case of straight-chain aliphatic esters, the yields of the corresponding 1-phenyl-1-alkanones were in the range of 41-51%. The presence of a methyl group in the α position of the ester (isobutyrate) reduced the yield of ketone strongly (11%); two methyl groups (pivalate) completely inhibited the reaction. The reactivity of a series of alkyl acetates was also studied in the cross-ketonisation reaction with ethyl benzoate over alumina. It has been found that secondary and tertiary alkyl acetates were slightly more selective than their primary counterparts due to the absence of products of transesterification. For these esters at 723 K the yields of acetophenone were in the range of 64-67%. The cross-ketonisation of a mixture of ethyl acetate with substituted ethyl benzoates led to the corresponding derivatives of acetophenone. It has been found that the position of the substituent in the benzene ring plays a crucial role in the reactivity of the ester and determines the extent of yield of the product. The highest yield of ketone (62%) was observed at 723 K for 3-methylacetophenone. 2-Methylacetophenone was formed with low yields (10%) in the whole range of reaction temperatures, probably due to steric effect in the ortho position. At 698 K the maximum yield of 4-methylacetophenone (27%) was attained. The ketonisation of ethyl acetate with ethyl esters of 4-t-butyl- and 4-chlorobenzoic acids led to moderate yields (24-27%) of 4-t-butyl- and 4-chloroacetophenone, respectively.
- Glinski,Koscik,Jerzak,Synoradzki
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p. 995 - 1001
(2007/10/03)
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- 1,2,4-Trioxepanes: Redox-cleavable protection for carbonyl groups
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(Chemical Equation Presented) 1,2,4-trioxepanes, readily prepared and easily handled derivatives of aldehydes and ketones, are stable to a variety of synthetic conditions and yet easily deblocked with Zn/HOAc or Mg/MeOH to regenerate the parent carbonyl. Trioxepanes may provide an alternative to 1,3-dithianes for acid-stable protection of carbonyl groups.
- Ahmed, Aqeel,Dussault, Patrick H.
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p. 3609 - 3611
(2007/10/03)
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- Catalytic ketonisation over oxide catalysts. Part VII. Ketonisation and cross-ketonisation of aliphatic esters over CeO2 and ZrO2 supported on alumina
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Catalysts of general formula xwt% MO2/Al2O 3, where x = 10, 20 or 30 and M = Ce or Zr have been studied in the ketonisation and cross-ketonisation of aliphatic esters under flow conditions between 548-723 K. Ketonisation of ethyl pentanoate, heptanoate and nonanoate has led to nonan-5-one, tridecan-7-one and heptadecan-9-one, respectively. The conversion of esters increased with temperature and at 698 K a quantitative conversion was observed, irrespective of the type of ester used. A maximum yield of ketone (46% for nonan-5-one, 60% for tridecan-7-one and 50% for heptadecan-9-one) was observed at 673 K. As a result of the cross-ketonisation of a mixture of ethyl pentanoate and ethyl nonanoate (3:1 molar ratio), three ketones were formed: nonan-5-one, tridecan-5-one and heptadecan-9-one. At 698 K, maximum yields of ketones were noted (37, 46 and 8%, respectively) together with a 90% conversion of esters. The catalysts were characterized by XRD, TPR and surface area measurements.
- Glinski,Szymanski,Lomot
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p. 1033 - 1038
(2007/10/03)
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- Synthesis and application of 2,6-dicarboxypyridinium chlorochromate as a new oxidizing reagent for alcohols, silyl ethers, and THP ethers under mild and non-aqueous conditions
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2,6-Dicarboxypyridinium chlorochromate can be used as a rapid, mild and efficient reagent for oxidation of alcohols, silyl ethers and THP ethers to their carbonyl compounds.
- Tajbakhsh, Mahmood,Hosseinzadeh, Rahman,Niaki, Mohammad Yazdani
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p. 508 - 510
(2007/10/03)
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- Kinetics and mechanism of the oxidation of secondary alcohols by tetrabutylammonium tribromide
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Oxidation of several secondary alcohols by tetrabutylammonium tribromide (TBATB) in aqueous acetic acid leads to the formation of corresponding ketones. The reaction is first order with respect to TBATB and the alcohols. The reaction failed to induce polymerization of acrylonitrile. There is no effect of tetrabutylammonium chloride on the reaction rate. The proposed reactive oxidizing species is tribromide ion. The oxidation of benzhydrol-α-d (PhCDOHPh) exhibited a substantial primary kinetic isotope effect (k H/kd = 5.15 at 298 K). The effect of solvent composition indicates that the rate increases with an increase in polarity of the solvent. The reaction is susceptible to both polar and steric effects of the substituents. A mechanism involving transfer of a hydride ion in the rate-determining step has been proposed.
- Gosain, Jaya,Sharma, Pradeep K.
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p. 815 - 818
(2007/10/03)
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- Synthesis and antimalarial activity of novel medium-sized 1,2,4,5-tetraoxacycloalkanes
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CsOH- or Ag2O-mediated cycloalkylation of (alkylidene)bisperoxides 3 and 1,n-dihaloalkanes (n = 3-8) provided the corresponding medium-sized 1,2,4,5-tetraoxacycloalkanes 4-8 in moderate yields. Subsequent evaluation of the antimalarial activity of the cyclic peroxides 4-8 in vitro and in vivo revealed that 1,2,6,7-tetraoxaspiro[7.11]nonadecane 4a has considerable potential as a new, inexpensive, and potent antimalarial drug.
- Kim,Nagai,Ono,Begum,Wataya,Hamada,Tsuchiya,Masuyama,Nojima,McCullough
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p. 2357 - 2361
(2007/10/03)
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- Synthesis of trisubstituted and tetrasubstituted alkenes via a manganate-induced migration-elimination process
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Preparation of alkenes via a manganate-induced alkylation-elimination sequence was investigated. The reaction of 2-alkoxy-1,1-dibromoalkanes with trialkylmanganates afforded disubstituted or trisubstituted alkenes. Treatment of 2-alkoxy-1,1,1-tribromoalkanes with trialkylmanganates provided trisubstituted or tetrasubstituted alkenes through bromine-metal exchange, transfer of two alkyl groups from manganese to carbon, and successive elimination of metal and the β-alkoxy moieties.
- Kakiya, Hirotada,Shinokubo, Hiroshi,Oshima, Koichiro
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p. 10063 - 10069
(2007/10/03)
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