Xn:Harmful;
110-43-0Relevant articles and documents
Ruthenium NNN complexes with a 2-hydroxypyridylmethylene fragment for transfer hydrogenation of ketones
Shi, Jing,Shang, Shu,Hu, Bowen,Chen, Dafa
, (2018)
Four NNN tridentate ligands L1–L4 containing 2-methoxypyridylmethene or 2-hydroxypyridylmethene fragment were synthesized and introduced to ruthenium centers. When (HOC5H3NCH2C5H3NC5H7N2) (L2) and (HOC5H3NCH2C5H3NC6H6N3) (L4) reacted with RuCl2(PPh3)3, two ruthenium chloride products Ru(L2)(PPh3)Cl2 (1) and Ru(L4)(PPh3)Cl2 (2) were isolated, respectively. Reactions of (MeOC5H3NCH2C5H3NC5H7N2) (L1) and (MeOC5H3NCH2C5H3NC6H6N3) (L3) with RuCl2(PPh3)3 in the presence of NH4PF6 generated two dicationic complexes [Ru(L1)2][PF6]2 (3) and [Ru(L3)2][PF6]2 (4), respectively. Complex 1 reacted with CO to afford product [Ru(L2)(PPh3)(CO)Cl][Cl]. The catalytic activity for transfer hydrogenation of ketones was investigated. Complex 1 showed the highest activity, with a turnover frequency value of 1.44?×?103?h?1 for acetophenone, while complexes 3 and 4 were not active.
Fragmentation and cleavage reactions mediated by SmI2. Part 1: X-Y, X-X and C-C substrates
Bradley,Williams,Blann, Kevin,Caddy, Judy
, p. 565 - 602 (2001)
-
REACTIVITE DES DERIVES ORGANOMANGANEUX-VIII; PREPARATION DE CETONES PAR ACYLATION D'ORGANOMANGANEUX. INFLUENCE DE LA NATURE DE L'AGENT ACYLANT, DES SOLVANTS ET DES LIGANDS
Friour, G.,Alexakis, A.,Cahiez, G.,Normant, J.
, p. 683 - 694 (1984)
The influence of the nature of acylating reagents, solvents and ligands on the preparation of ketones by acylation of organomanganous reagents is studied.Thus acid chlorides in ether, symmetrical acid anhydrides in ether or THF and mixed carboxylic-carbonic anhydrides (R'COOCOOEt) in ether are compared, they lead to the corresponding ketones with good or excellent yields.Some problems of reproductibility are encountered and discussed when mixed anhydrides R'COOCOOEt are used in THF.The addition of a great variety of cosolvents (e.g.C6H6, AcOEt, CO3Et2, CH3CN, CH2Cl2...) to the reaction mixture before addition of the acylating reagent does not affect the yield of ketones.In comparison the complexation of organomanganous reagents by several ligands (e.g.Me2S or Ph3P) has no subsequent effect on their acylation.The main limitation for the choice of solvents or ligands is the use of amino derivatives which generally lead to a very low yield of ketones (e.g.C5H5N, TMEDA, Et3N) or unreproducible yields (e.g.HMPA).Two applications of these studies are described: -The stabilization of s or t-alkyl manganous derivatives by complexation which leads to the best yield of the corresponding ketones -The use of a cosolvent in order to increase the yield when mixed anhydrides R'COOCOOEt are used in THF.
Oxidation of Higher Alcanols by Tetra-1-butylammonium Permanganate
Holba, V.,Sumichrast, R.
, p. 681 - 686 (1995)
Oxidations of hexan-1-ol, hexan-2-ol, hexan-3-ol, heptan-1-ol, heptan-2-ol, octan-1-ol, and octan-2-ol with tetra-1-butylammonium permanganate, dissolved in the same alcohols, proceed partly autocatalytically.The rate constants of both catalytic and non-catalytic reactions have been evaluated.Colloidal manganese dioxide, one of the reaction products, has been identified as the catalyst. - Keywords: Autocatalysis; Kinetic parameters; Colloidal MnO2
Iwanow et al.
, p. 903,904,906 (1950)
Diazo chemistry controlling the selectivity of olefin ketonisation by nitrous oxide
Hermans, Ive,Moens, Bart,Peeters, Jozef,Jacobs, Pierre,Sels, Bert
, p. 4269 - 4274 (2007)
The thermal reaction of olefins with nitrous oxide was recently put forward as a promising synthetic ketone source. The 1,3-dipolar cycloaddition of N 2O to the C=C double bond, forming a 4,5-dihydro-[1,2,3]oxadiazole intermediate, was predicted to be the first elementary reaction step. This oxadiazole can subsequently decompose to the desired carbonyl product and N 2 via a hydrogen shift. In this contribution, Potential Energy Surfaces are constructed at the reliable G2M level of theory and used to evaluate thermal rate constants by Transition State Theory. Compelling theoretical and experimental evidence is presented that an oxadiazole intermediate not only can undergo a hydrogen shift, but eventually also a methyl- or even an alkyl-shift. Special emphasis is also given on a hitherto neglected decomposition of the oxadiazole via a concerted C-C and N-O cleavage. For some substrates, such as internal olefins, this diazo route is negligibly slow, compared to the ketone path, leaving no marks on the selectivity. For cyclopentene the diazo cleavage was however found to be nearly as fast as the desired ketone route. However, the diazo compound, viz. 5-diazopentanal, reconstitutes the oxadiazole much faster upon ring-closure than it is converted to side-products. Therefore, a pre-equilibrium between the diazoalkanal and the oxadiazole is established, explaining the high ketone yield. On the other hand, for primary alkenes, such a concerted C-C and N-O cleavage to diazomethane is identified as an important side reaction, producing aldehydes with the loss of one C-atom. For these substrates, the bimolecular back-reaction of the C n-1 aldehyde and diazomethane is too slow to sustain an equilibrium with the oxadiazole; diazomethane rather reacts with the substrate to form cyclopropane derivatives. The overall selectivity is thus determined by a combination of H-, methyl- or alkyl-shift, and the eventual impact of a diazo cleavage in the oxadiazole intermediate. the Owner Societies.
-
Suzuki et al.
, p. 5708 (1967)
-
-
Reeve,Adkins
, p. 2874 (1940)
-
EVIDENCE FOR A SINGLE ELECTRON TRANSFER MECHANISM IN THE REDUCTION OF BENZOPHENONE WITH LITHIUM ALKOXIDES
Ashby, E. C.,Argyropoulos, J. N.
, p. 465 - 468 (1986)
The reduction of benzophenone by lithium alkoxides gives rise to benzophenone ketyl which disappears in a first-order fashion and whose first-order rate constant is approximately equal to the pseudo-first-order rate constant for the formation of the product, benzhydrol.
Metal-Free catalyst for visible-light-induced oxidation of unactivated alcohols using Air/Oxygen as an oxidant
Schilling, Waldemar,Riemer, Daniel,Zhang, Yu,Hatami, Nareh,Das, Shoubhik
, p. 5425 - 5430 (2018)
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.
Oxidation of s-Alcohols with "Oxone" in Aprotic Solvents in the Presence of Wet-Aluminium Oxide
Hirano, Masao,Oose, Masaki,Morimoto, Takashi
, p. 1046 - 1047 (1991)
The oxidation of secondary aliphatic, alicyclic, and benzylic alcohols with Oxone in aprotic solvents in the presence of "wet-aluminum oxide" afforded the corresponding ketones in good yields under mild conditions.
Parallel interconnected kinetic asymmetric transformation (PIKAT) with an immobilized ω-transaminase in neat organic solvent
B?hmer, Wesley,Koenekoop, Lucien,Mutti, Francesco G.,Simon, Timothée
, (2020)
Comprising approximately 40% of the commercially available optically active drugs, α-chiral amines are pivotal for pharmaceutical manufacture. In this context, the enzymatic asymmetric amination of ketones represents a more sustainable alternative than traditional chemical procedures for chiral amine synthesis. Notable advantages are higher atom-economy and selectivity, shorter synthesis routes, milder reaction conditions and the elimination of toxic catalysts. A parallel interconnected kinetic asymmetric transformation (PIKAT) is a cascade in which one or two enzymes use the same cofactor to convert two reagents into more useful products. Herein, we describe a PIKAT catalyzed by an immobilized ω-transaminase (ωTA) in neat toluene, which concurrently combines an asymmetric transamination of a ketone with an anti-parallel kinetic resolution of an amine racemate. The applicability of the PIKAT was tested on a set of prochiral ketones and racemic α-chiral amines in a 1:2 molar ratio, which yielded elevated conversions (up to >99%) and enantiomeric excess (ee, up to >99%) for the desired products. The progress of the conversion and ee was also monitored in a selected case. This is the first report of a PIKAT using an immobilized ωTA in a non-aqueous environment.
-
Hawkins
, p. 2801,2803 (1950)
-
Catalysts for convenient aerobic alcohol oxidations in air: Systematic ligand studies in Pd/pyridine systems
John, Lukas C.,Gunay, Ahmet,Wood, Andrew J.,Emmert, Marion H.
, p. 5758 - 5764 (2013)
We report highly convenient Pd catalysts for the aerobic oxidation of alcohols, which are generated in situ by combining commercially available catalyst precursors. Systematic optimizations of the L- and X-type ligand environment and the employed additive allow the use of air as the sole oxidant without formation of Pd black. The resulting novel protocol provides quantitative yields of a broad variety of ketones and aldehydes.
Nanocomposite shuttle-supported palladium nanoparticles as a PH-triggered phase transfer catalyst for the aerobic oxidation of alcohols
Zhu, Yaoqin,Xu, Jia,Lu, Ming
, p. 1213 - 1219 (2015)
Abstract We synthesize a novel mesoporous nanocomposite shuttle. It can reversibly transfer between the organic and water phase in response to pH. It was used as the precursor to load palladium nanoparticles for the aerobic oxidation of alcohols. The whole oxidation process with the catalyst is highly efficient and chemo-selective. The nanocomposite shuttle can take Pd nanoparticles to an organic phase for catalyzing, and then come back to the aqueous phase, thus benefiting the separation and recycling of the catalysts. The catalyst is stable and can be reused for at least five runs. The catalyst we discovered not only makes the whole reaction homogeneous, but can also can be separated by decanting.
Direct oxidative esterification of primary alcohols and oxidation of secondary alcohols over mesoporous spherical silica encapsulated MnO2 nanoparticles
Hosseinzadeh, Shahram Zare,Babazadeh, Mirzaagha,Shahverdizadeh, Gholam Hossein,Hosseinzadeh-Khanmiri, Rahim
, p. 9491 - 9499 (2019)
In this work, a simple and efficient strategy for the fabrication of novel encapsulated MnO2 nanoparticles inside spherical mesoporous silica hollow-nanoparticles was described. They were synthesized by consecutively anchoring MnO2 nanoparticles on poly(styrene-co-methacrylic acid) particles, coating with a mesoporous silica shell, and subsequently removing the polymeric core by dissolving in acetone. The catalytic activity of the nanoparticles was examined in the aerobic oxidation of various primary and secondary alcohols, which showed good activity and selectivity for the transformation of primary alcohols to the corresponding esters through the oxidative esterification process and secondary alcohols to ketones in short reaction times under mild reaction conditions. In addition, the catalyst system was utilized for the oxidation of primary alcohols to aldehydes using tert-butyl hydroperoxide (TBHP) as an oxidant under mild conditions and produced an excellent product yield.
Surface-mediated highly efficient oxidation of alcohols by bismuth nitrate
Samajdar,Becker,Banik
, p. 2691 - 2695 (2001)
Montmorillonite impregnated with bismuth nitrate was found to be an excellent reagent for the oxidation of a variety of alcohols in excellent yield.
Zeolite-confined nano-RuO2: A green, selective, and efficient catalyst for aerobic alcohol oxidation
Zhan, Bi-Zeng,White, Mary Anne,Sham, Tsun-Kong,Pincock, James A.,Doucet, Rene J.,Rao, K.V. Ramana,Robertson, Katherine N.,Cameron, T. Stanley
, p. 2195 - 2199 (2003)
The development of green, selective, and efficient catalysts, which can aerobically oxidize a variety of alcohols to their corresponding aldehydes and ketones, is of both economic and environmental significance. We report here the synthesis of a novel aerobic oxidation catalyst, a zeolite-confined nanometersized RuO2 (RuO2-FAU), by a one-step hydrothermal method. Using the spatial constraints of the rigid zeolitic framework, we sucessfully incorporated RuO2 nanoparticles (1.3 ± 0.2 nm) into the supercages of faujasite zeolite. Ru K-edge X-ray absorption fine structure results indicate that the RuO2 nanoclusters anchored in the zeolite are structurally similar to highly hydrous RuO2; that is, there is a two-dimensional structure of independent chains, in which RuO6 octahedra are connected together by two shared oxygen atoms. In our preliminary catalytic studies, we find that the RuO2 nanoclusters exhibit extraordinarily high activity and selectivity in the aerobic oxidation of alcohols under mild conditions, for example, air and ambient pressure. The physically trapped RuO2 nanoclusters cannot diffuse out of the relatively narrow channels/pores of the zeolite during the catalytic process, making the catalyst both stable and reusable.
Catalytic hypervalent iodine oxidation of alcohols to corresponding aldehydes or ketones using 2,2,6,6-tetramethylpiperidinyl-1-oxy and potassium peroxodisulfate
Zhu, Chenjie,Ji, Lei,Wei, Yunyang
, p. 327 - 331 (2010)
An efficient, facile, and mild oxidation of alcohols to the corresponding aldehydes or ketones with potassium peroxodisulfate and 2,2,6,6- tetramethylpiperidinyl-1-oxy in the presence of a catalytic amount of iodobenzene is reported. The oxidation proceeded in a mixed solvent to afford carbonyl compounds in moderate to excellent yields. A possible mechanism for the oxidation is proposed.
Selective dehydrogenation of alcohols and diols catalyzed by a dihydrido iridium PCP pincer complex
Morales-Morales,Redon,Wang,Lee,Yung,Magnuson,Jensen
, p. 823 - 829 (2001)
The PCP pincer complex, IrH2{C6H3-2,6-(CH2P-t-Bu 2)2} (1) catalyzes the transfer dehydrogenation of primary and secondary alcohols. Dehydrogenation occurs across the C - O bond rather than the C - C bonds and the corresponding aldehydes or ketones are obtained as the sole products arising from the dehydrogenation reactions. Methanol is an exception to this pattern of reactivity and undergoes only stoichiometric dehydrogenation with 1 to give the carbonyl complex, Ir(CO){C6H3-2,6-(CH2P-t-Bu2) 2} (2). The products are obtained in nearly quantitative yields when the reactions are carried out in toluene solutions. Under the same conditions, 2,5-hexanediol is converted to the annulated product, 3-methyl-2-cyclopenten-1-one which has been isolated in 91% yield in a preparative scale reaction.
Screening, Molecular Cloning, and Biochemical Characterization of an Alcohol Dehydrogenase from Pichia pastoris Useful for the Kinetic Resolution of a Racemic β-Hydroxy-β-trifluoromethyl Ketone
Bulut, Dalia,Hummel, Werner,Gr?ger, Harald,Duangdee, Nongnaphat,Berkessel, Albrecht
, p. 1349 - 1358 (2016)
The stereoselective synthesis of chiral 1,3-diols with the aid of biocatalysts is an attractive tool in organic chemistry. Besides the reduction of diketones, an alternative approach consists of the stereoselective reduction of β-hydroxy ketones (aldols). Thus, we screened for an alcohol dehydrogenase (ADH) that would selectively reduce a β-hydroxy-β-trifluoromethyl ketone. One potential starting material for this process is readily available by aldol addition of acetone to 2,2,2-trifluoroacetophenone. Over 200 strains were screened, and only a few yeast strains showed stereoselective reduction activities. The enzyme responsible for the reduction of the β-hydroxy-β-trifluoromethyl ketone was identified after purification and subsequent MALDI-TOF mass spectrometric analysis. As a result, a new NADP+-dependent ADH from Pichia pastoris (PPADH) was identified and confirmed to be capable of stereospecific and diastereoselective reduction of the β-hydroxy-β-trifluoromethyl ketone to its corresponding 1,3-diol. The gene encoding PPADH was cloned and heterologously expressed in Escherichia coli BL21(DE3). To determine the influence of an N- or C-terminal His-tag fusion, three different recombinant plasmids were constructed. Interestingly, the variant with the N-terminal His-tag showed the highest activity; consequently, this variant was purified and characterized. Kinetic parameters and the dependency of activity on pH and temperature were determined. PPADH shows a substrate preference for the reduction of linear and branched aliphatic aldehydes. Surprisingly, the enzyme shows no comparable activity towards ketones other than the β-hydroxy-β-trifluoromethyl ketone.
Borunova et al.
, (1972)
STERIC EFFECTS IN THE REACTION OF DI(BROMOMAGNESIO)ALKANES WITH CARBOXYLIC ESTERS
Canonne, Persephone,Belanger, Denis,Lemay, Gilles
, p. 4995 - 4998 (1981)
Largely different product distributions were observed on the action of various carboxylic esters with 1,4-di(bromomagnesio)butane and its homologue 1,5-di(bromomagnesio)pentane.The much larger yields of reduction product with the latter are the evidence for the structural geometric requirements for the annelation step.
Efficient and selective green oxidation of alcohols by MOF-derived magnetic nanoparticles as a recoverable catalyst
Yao, Xianfang,Bai, Cuihua,Chen, Junying,Li, Yingwei
, p. 26921 - 26928 (2016)
A simple and highly efficient synthesis strategy for the green oxidation of alcohols to corresponding carbonyl products is developed using a heterogeneous non-noble magnetic Fe3O4@C catalyst. The magnetic nanocomposites were prepared by one-pot thermal decomposition of a Fe-containing MOF and fully characterized by powder X-ray diffraction (PXRD), N2 physical adsorption, atomic absorption spectroscopy (AAS), element analysis, scanning electronic microscopy (SEM), and transmission electron microscopy (TEM). The catalytic activities of Fe3O4@C materials were investigated in the selective oxidation of alcohols in neat water using hydrogen peroxide as a green oxidant under base-free conditions. Besides the high activity and selectivity to the target products, the proposed catalytic system features a broad substrate scope for both aryl and alkyl alcohols. Moreover, the magnetically catalyst could be easily separated by using an external magnetic field and reused for at least four times without significant loss in catalytic efficiency under the investigated conditions.
-
Bel'skii
, (1962)
-
Identification of key oxidative intermediates and the function of chromium dopants in PKU-8: catalytic dehydrogenation ofsec-alcohols withtert-butylhydroperoxide
Wang, Weilu,He, Yang,He, Junkai,Dang, Yanliu,Kankanmkapuge, Tharindu,Gao, Wenliang,Cong, Rihong,Suib, Steven L.,Yang, Tao
, p. 1365 - 1374 (2021/03/14)
Catalytic oxidation reaction using green oxidants plays an important role in modern chemical engineering; however, thein situgenerated active species and the related catalytic mechanism need to be understood in depth. For this purpose, Cr-substituted aluminoborate Cr-PKU-8 catalysts were synthesized and applied as recyclable heterogeneous catalysts for the oxidation of aliphatic and aromatic alcohols usingtert-butylhydroperoxide (TBHP). Both high efficiency and selectivity (>99%) were achieved during the dehydrogenation of varioussec-alcohols into acetone in H2O solvent medium. From the analyses using isotopic tracer, molecular probe and cyclic voltammetry strategies, the chromium ions were observed to undergo a Cr3+-Cr2+-Cr3+redox cycle. DFT calculations suggest thatt-BuOO* is more energetically favourable for hydrogen abstraction fromsec-alcohol thant-BuO*, and probably acts as the key active species. Accordingly, the reaction scheme was proposed to interpret the catalytic process based on the observed results.
Novel oxidovanadium complexes with redox-active r-mian and r-bian ligands: Synthesis, structure, redox and catalytic properties
Fomenko, Iakov S.,Fukin, Georgy K.,Gongola, Marko I.,Gushchin, Artem L.,Ikonnikov, Nikolay S.,Ketkov, Sergey Y.,Lukoyanov, Anton N.,Nadolinny, Vladimir A.,Novikov, Alexander S.,Rumyantcev, Roman V.,Shul’pin, Georgiy B.,Shul’pina, Lidia S.,Sokolov, Maxim N.
, (2021/09/28)
A new monoiminoacenaphthenone 3,5-(CF3)2C6H3-mian (complex 2) was synthesized and further exploited, along with the already known monoiminoacenaphthenone dpp-mian, to obtain oxidovanadium(IV) complexes [VOCl2(dpp-mian)(CH3CN)] (3) and [VOCl(3,5-(CF3)2C6H3-bian)(H2O)][VOCl3(3,5-(CF3)2C6H3-bian)]·2.85DME (4) from [VOCl2(CH3CN)2(H2O)] (1) or [VCl3(THF)3]. The structure of all compounds was determined using X-ray structural analysis. The vanadium atom in these structures has an octahedral coordination environment. Complex 4 has an unexpected structure. Firstly, it contains 3,5-(CF3)2C6H3-bian instead of 3,5-(CF3)2C6H3-mian. Sec-ondly, it has a binuclear structure, in contrast to 3, in which two oxovanadium parts are linked to each other through V=O···V interaction. This interaction is non-covalent in origin, according to DFT calculations. In structures 2 and 3, non-covalent π-π staking interactions between acenaphthene moieties of the neighboring molecules (distances are 3.36–3.40 ?) with an estimated energy of 3 kcal/mol were also found. The redox properties of the obtained compounds were studied using cyclic voltammetry in solution. In all cases, the reduction processes initiated by the redox-active nature of the mian or bian ligand were identified. The paramagnetic nature of complexes 3 and 4 has been proven by EPR spectroscopy. Complexes 3 and 4 exhibited high catalytic activity in the oxidation of alkanes and alcohols with peroxides. The yields of products of cyclohexane oxidation were 43% (complex 3) and 27% (complex 4). Based on the data regarding the study of regio-and bond-selectivity, it was concluded that hydroxyl radicals play the most crucial role in the reaction. The initial products in the reactions with alkanes are alkyl hydroperoxides, which are easily reduced to their corresponding alcohols by the action of triphenylphosphine (PPh3). According to the DFT calculations, the difference in the catalytic activity of 3 and 4 is most likely associated with a different mechanism for the generation of?OH radicals. For complex 4 with electron-withdrawing CF3 substituents at the diimine ligand, an alternative mechanism, different from Fenton’s and involving a redox-active ligand, is assumed.
METHOD FOR PRODUCING HIGHER LINEAR FATTY ACIDS OR ESTERS
-
Page/Page column 33-33, (2021/11/26)
The present invention relates to a method of producing linear fatty acids comprising 7 to 28 carbon atoms or esters thereof using a combined biotechnological and chemical method. In particular, the present invention relates to a method of producing dodecanoic acid (i.e. lauric acid), via higher alkanones, preferably 6-undecanone.
