- Selective aerobic oxidation of isophorone catalyzed by molybdovanadophosphate supported on carbon (NPMoV/C)
-
Isophorone was smoothly oxidized with molecular oxygen by molybdovanadophosphate supported on the active carbon ((NPMoV/C) to give 3-formyl-5,5-dimethyl-2-cyclohexen-1-one in relatively high selectivity. The regioselectivity of the oxidation by NPMoV/C was found to be just opposite to that of the conventional oxidations, The pore size of the supports appears to be an important factor governing the regioselectivity.
- Hanyu, Atsushi,Sakurai, Yasunori,Fujibayashi, Shinya,Sakaguchi, Satoshi,Ishii, Yasutaka
-
-
Read Online
- Chitosan-based Schiff base-metal complexes (Mn, Cu, Co) as heterogeneous, new catalysts for the β-isophorone oxidation
-
A new chitosan-based Schiff base was prepared and complexed with manganese, cobalt and copper. These Schiff base metal complexes were used as heterogeneous catalysts for the air oxidation of β-isophorone to ketoisophorone. The obtained complexes were characterized by means of FT-IR,1HNMR spectroscopy, elemental analysis, powder X-ray diffraction, field emission gun scanning electron microscopy, electron spin resonance spectroscopy, ICP-AES and solubility tests. Thermal properties were also investigated using thermal gravimetric analysis. Data obtained by thermal analysis revealed that these complexes showed good thermal stability. The conversion and selectivity of β-isophorone to ketoisophorone for each prepared catalyst was studied using a batch reactor and gas chromatography for product identification and quantification. The results were compared against the homogeneous bis-salicylaldehyde ethylenedi-imine-Mn catalyst. The use of methanol, acetone, methyl isobutyl ketone and n-hexane as solvent and its effect on conversion and selectivity was also investigated. Acetone was found to be a promising solvent for the β-isophorone oxidation. The role of triethyl amine and acetyl acetone in the oxidation reaction has also been investigated.
- Thatte,Rathnam,Pise
-
-
Read Online
- Selective synthesis of 4-hydroxyisophorone and 4-ketoisophorone by fungal peroxygenases
-
The recently discovered unspecific peroxygenases (UPOs) from the ascomycetes Chaetomium globosum and Humicola insolens were capable of selectively hydroxylating isophorone to 4-hydroxyisophorone (4HIP) and 4-ketoisophorone (4KIP), which are substrates of interest for the pharmaceutical and flavor-and-fragrance sectors. The model UPO from the basidiomycete Agrocybe aegerita was less regioselective, forming 7-hydroxyisophorone (and 7-formylisophorone) in addition to 4HIP. However, it was the most stereoselective UPO yielding the S-enantiomer of 4HIP with 88% ee. Moreover, using H. insolens UPO full kinetic resolution of racemic HIP was obtained within only 15 min, with >75% recovery of the R-enantiomer. Surprisingly, the UPOs from two other basidiomycetes, Marasmius rotula and Coprinopsis cinerea, failed to transform isophorone. The different UPO selectivities were rationalized by computational simulations, in which isophorone and 4HIP were diffused into the enzymes using the adaptive PELE software, and the distances from heme-bound oxygen in H2O2-activated enzyme to different substrate atoms, and the corresponding binding energies were analyzed. Interestingly, for process upscaling, full conversion of 10 mM isophorone was achieved with H. insolens UPO within nine hours, with total turnover numbers up to 5500. These biocatalysts, which only require H2O2 for activation, may represent a novel, simple and environmentally-friendly route for the production of isophorone derivatives.
- Aranda, Carmen,Municoy, Martí,Guallar, Víctor,Kiebist, Jan,Scheibner, Katrin,Ullrich, René,Del Río, José C.,Hofrichter, Martin,Martínez, Angel T.,Gutiérrez, Ana
-
-
Read Online
- Stereoselective hydroxylation of isophorone by variants of the cytochromes P450 CYP102A1 and CYP101A1
-
The stereoselective oxidation of hydrocarbons is an area of research where enzyme biocatalysis can make a substantial impact. The cyclic ketone isophorone was stereoselectively hydroxylated (≥95%) by wild-type CYP102A1 to form (R)-4-hydroxyisophorone, an important chiral synthon and flavour and fragrance compound. CYP102A1 variants were also selective for 4-hydroxyisophorone formation and the product formation rate increased over the wild-type enzyme by up to 285-fold, with the best mutants being R47L/Y51F/I401P and A74G/F87V/L188Q. The latter variant, which contained mutations in the distal substrate binding pocket, was marginally less selective. Combining perfluorodecanoic acid decoy molecules with the rate accelerating variant R47L/Y51F/I401P engendered further improvement with the purified enzymes. However when the decoy molecules were used with A74G/F87V/L188Q the amount of product generated by the enzyme was reduced. Addition of decoy molecules to whole-cell turnovers did not improve the productivity of these CYP102A1 systems. WT CYP101A1 formed significant levels of 7-hydroxyisophorone as a minor product alongside 4-hydroxyisophorone. However the F87W/Y96F/L244A/V247L CYP101A1 mutant was ≥98% selective for (R)-4-hydroxyisophorone. A comparison of the two enzyme systems using whole-cell oxidation reactions showed that the best CYP101A1 variant was able to generate more product. We also characterised that the further oxidation metabolite 4-ketoisophorone was produced and then subsequently reduced to levodione by an endogenous Escherichia coli ene reductase.
- Dezvarei, Shaghayegh,Lee, Joel H.Z.,Bell, Stephen G.
-
-
Read Online
- Enhanced catalytic activity and selectivity in oxidation of α-isophorone to ketoisophorone with phosphomolybdic acid
-
Aerobic allylic oxidation of α-isophorone with phosphomolybdic acid as catalyst in combination with DMSO and potassium tert-butoxide provides ketoisophorone in unprecedented high yield. This study suggests that the solvent can play a pivotal role in directing selectivity in allylic oxidations of highly substituted cyclic olefins.
- Murphy,Schneider,Mallat,Baiker
-
-
Read Online
- THE OXIDATION OF 2-CYCLOHEXEN-1-ONES TO 2-CYCLOHEXENE-1,4-DIONES
-
Treatment of 5,5-dimethyl-2-cyclohexen-1-one and isophorone with phosphomolybdic acid, potassium dichromate, cupric sulfate, and air gives 5,5-dimethyl- and 3,5,5-trimethyl-2-cyclohexene-1,4-dione, respectively.In the latter reaction treatment of the crude product with aqueous base leads to the formation of 2,3,6,6-tetramethylanthracene-1,4,5,8-tetrone.
- Freer, Vernon, J.,Yates, Peter
-
-
Read Online
- Kinetics Study on Oxidation of β-Isophorone Using Molecular Oxygen
-
The oxidation kinetics of β-isophorone (β-IP) using molecular oxygen catalyzed by iron(III) acetylacetonate was investigated in a lab-scale agitator bubbling reactor. β-IP was found to give keto-isophorone (KIP) and 4-hydroxy-3,5,5-trimethyl-2-cyclohexen-1-one (HIP) along with little isomerization product α-isophorone (α-IP). The results show that the oxidation reaction took place in the pseudo-first-order fast reaction regime. The experiment was conducted under the mass transfer reaction regime as the mass transfer resistances could not be easily eliminated. The intrinsic kinetics was obtained through apparent kinetics. The activation energy of oxidation of β-IP to KIP is 70.5 ± 4.1 kJ mol-1, and the value of ln AKIP is 33.53 ± 1.22. Meanwhile, the activation energy of oxidation of β-IP to HIP is 86.4 ± 5.4 kJ mol-1 and the value of ln AHIP is 36.23 ± 1.52, which could provide theoretical basis for industrial design, amplification of reactor, and the optimization of reaction.
- Chen, Zhirong,Fang, Tingting,Yuan, Shenfeng,Yin, Hong
-
-
Read Online
- Unexpected oxidation of β-isophorone with molecular oxygen promoted by TEMPO
-
A novel and efficient protocol for the oxidation of β-isophorone (β-IP) using molecular oxygen without any additives catalyzed by 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) has been established. The generally accepted catalytic mechanism of alcohols by the oxoammonium cation (TEMPO+) derived from TEMPO indeed fails to explain our experimental observations, because a favorable radical-based process is confirmed by electron spin resonance measurements. Our results show that a plateau of the time-dependence curve is observed in the oxidation of β-IP with TEMPO at low temperature, which is quite different from that of N-hydroxyphthalimide (NHPI). The proposed mechanism of this catalytic process is also compared with that of NHPI. The theoretically characterized reaction pathways show that unlike the phthalimide N-oxyl radical, TEMPO promotes the oxidation via its interaction with the active intermediate hydroperoxide (ROOH) rather than its initial interaction with β-IP, and byproduct water also assists the α-H atom transfer from ROOH to TEMPO. In addition to the intensive oxidation of alcohols catalyzed by TEMPO, the present study widens its specific applications in the active C-H bonds of hydrocarbons, and also provides new insights into its promoted metal-free oxidation. This journal is the Partner Organisations 2014.
- Jia, Lu,Chen, Kexian,Wang, Congmin,Yao, Jia,Chen, Zhirong,Li, Haoran
-
-
Read Online
- Combination of two catalytic sites in a novel nanocrystalline TiO 2-iron tetrasulfophthalocyanine material provides better catalytic properties
-
Mesoporous titania nanocrystals containing iron tetrasulfophthalocyanine (FePcS) have been synthesised by a one-pot hydrolytic process from a modified Ti alkoxide; the novel hybrid catalyst was efficient in heterogeneous oxidation of 2,3,6-trimethylphenol and β-isophorone suggesting a cooperative effect between TiO2 and FePcS catalytic sites. The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2005.
- Beyrhouty, Mirvat,Sorokin, Alexander B.,Daniele, Stephane,Hubert-Pfalzgraf, Liliane G.
-
-
Read Online
- Oxidation-isomerization of an olefin to allylic alcohol using titania-silica and a base co-catalyst
-
The allylic oxidation of olefins is essential in synthetic organic chemistry, affording valuable α,β-unsaturated alcohols and carbonyl compounds. Allylic oxidation maintains the olefinic functionality in the product, thereby allowing further useful transformations. The potential two-step, one-pot synthesis of α,β-unsaturated alcohols from olefins was illustrated on the example of 4-hydroxyisophorone using titania-silica aerogels and basic co-catalysts. Kinetic analysis of the complex reaction network revealed that titania-silica was efficient in the epoxidation of β-isophorone (3,5,5-trimethyl-3-cyclohexen-1-one) with tert-butylhydroperoxide at 353 K, whereas the acid/base-catalyzed in situ rearrangement to 4-hydroxy-isophorone (4-hydroxy-3,5,5-trimethyl-cyclohex-2-eonone) was slow. Addition of solid bases such as CaO, Na2CO3 and KF/CaF2 accelerated the rearrangement and achieved ≤ 77.5% selectivity at 83% conversion in 3 hr. Stronger bases K2CO3, BaO, Mg-Al-O-tBu, guanidine bases) inhibited the epoxidation reaction due to the deactivation of the isolated Ti sites and favored isomerization of β-isophorone to α-isophorone. Hydrophobization of titania-silica by covalently bound surface phenyl groups greatly suppressed oligomerization and isomerization of β-isophorone but did not improve selectivity to 4-hydroxyl-isophorone.
- Beck,Mallat,Baiker
-
-
Read Online
- ELECROCATALYTIC OXIDATION OF OLEFINES AND KETONES BASED ON A RuIV=O/RuII-H2O SYSTEM
-
An electrocatalytic procedure is described for the oxidation of cyclohexene, safrole, isosafrole, isophorone, deoxybenzoin and acetophenone using the RuIV oxidant IV(trpy)(bpy)O>2+.The relative reactivities of the substrates are presented.
- Madurro, Joao Marcos,Chiericato, Glaico Jr.,Giovani, Wagner F.De,Romero, Jose Ricardo
-
-
Read Online
- Method for continuously and efficiently preparing 2, 6, 6-trimethyl-2-cyclohexene-1, 4-diketone by oxidation
-
The invention discloses a method for continuously and efficiently preparing 2, 6, 6-trimethyl-2-cyclohexene-1, 4-diketone by oxidation. The method includes the steps: (1) performing reaction of raw material liquid and oxygen-containing gas in a spraying and mixing manner to obtain reaction liquid; (2) performing gas-liquid separation on the reaction liquid, adjusting temperature of a liquid phase,and performing reaction of the liquid phase and the oxygen-containing gas in a spraying and mixing manner to obtain reaction liquid; (3) repeating process of the step (2) until reaction is complete to obtain 2, 6, 6-trimethyl-2-cyclohexene-1, 4-diketone liquid. The oxygen-containing gas in the step (2) is a gas phase acquired by gas-liquid separation or newly prepared gas. The raw material liquidcomprises a catalyst, a reaction raw material and a solvent. By the aid of a gas and liquid mixing and spraying mode, the mixing effect of the reaction liquid, the gas and the catalyst is greatly superior to that of a mechanically stirred reactor, bubbles are more uniformly dispersed and sufficiently contact, ideal mass transfer effects are achieved, and reaction is accelerated.
- -
-
Paragraph 0048-0054
(2019/04/09)
-
- Synthesis method of oxo-isophorone
-
The invention relates to a synthesis method of oxo-isophorone. The method is characterized in that 3, 5, 5-trimethyl-4-hydroxyl-2-cyclohexene-1-one (HIP) is used as a raw material, p-benzoquinone compounds (II) are used as an oxidizing agent and a catalyst; oxygen or air is introduced, and an oxidation reaction is carried out in an inert solvent, so that the oxo-isophorone (KIP) and hydroquinone compounds (III) are generated.
- -
-
Paragraph 0048-0062; 0064
(2019/03/28)
-
- Combining Photo-Organo Redox- and Enzyme Catalysis Facilitates Asymmetric C-H Bond Functionalization
-
In this study, we combined photo-organo redox catalysis and biocatalysis to achieve asymmetric C–H bond functionalization of simple alkane starting materials. The photo-organo catalyst anthraquinone sulfate (SAS) was employed to oxyfunctionalise alkanes to aldehydes and ketones. We coupled this light-driven reaction with asymmetric enzymatic functionalisations to yield chiral hydroxynitriles, amines, acyloins and α-chiral ketones with up to 99 % ee. In addition, we demonstrate functional group interconversion to alcohols, esters and carboxylic acids. The transformations can be performed as concurrent tandem reactions. We identified the degradation of substrates and inhibition of the biocatalysts as limiting factors affecting compatibility, due to reactive oxygen species generated in the photocatalytic step. These incompatibilities were addressed by reaction engineering, such as applying a two-phase system or temporal and spatial separation of the catalysts. Using a selection of eleven starting alkanes, one photo-organo catalyst and 8 diverse biocatalysts, we synthesized 26 products and report for the model compounds benzoin and mandelonitrile > 97 % ee at gram scale.
- Zhang, Wuyuan,Fueyo, Elena Fernandez,Hollmann, Frank,Martin, Laura Leemans,Pesic, Milja,Wardenga, Rainer,H?hne, Matthias,Schmidt, Sandy
-
supporting information
p. 80 - 84
(2019/01/04)
-
- CATALYTIC OXIDATION OF 3,5,5-TRIMETHYLCYCLOHEXA-3-ENE-1-ONE (?-ISOPHORONE) WITH HYDROGEN PEROXIDE TO AFFORD 2,6,6-TRIMETHYL-2-CYCLOHEXENE-1,4-DIONE (KETO-ISOPHORONE)
-
The present invention provides a novel process for producing 2,6,6-trimethyl-2-cyclohexene-1,4-dione (keto-isophorone) by catalytic oxidation of 3,5,5-trimethylcyclohexa-3-ene-1-one (β-isophorone) with hydrogen peroxide as the oxidant. In particular, the novel process includes phase transfer reagent in a biphasic system including an organic phase and an aqueous phase wherein the biphasic system includes 1) a tungsten polyoxyometallate as catalyst and hydrogen peroxide, and/or 2) a mixture of a) a mineral acid, b) hydrogen peroxide, and c) a metal tungstate.
- -
-
Page/Page column 0059-0060; 0061-0063; 0064-0066; 0067-0068
(2018/06/15)
-
- Preparation method of trimethylhydroquinone
-
The invention discloses a preparation method of trimethylhydroquinone. The preparation method is characterized in that isophorone is used as an initial raw material and oxidized into oxoisophorone, then an acylation reaction occurs in the oxoisophorone and an acylating agent to produce trimethyl hydroquinone diester, and the trimethyl hydroquinone diester is hydrolyzed to produce 2,3,5-trimethylhydroquinone. The method disclosed by the invention has cheap and easily-available raw materials and simple syntheses steps, a used solvent is easy to recover and reuse, and the method needs not use ofa big amount of acid and alkali, thereby reducing pollution of the environment, being convenient for large-scale industrial production and having good application prospects.
- -
-
Paragraph 0037; 0038; 0045; 0046; 0053; 0054; 0061; 0062
(2019/01/07)
-
- One-Pot Biocatalytic Double Oxidation of α-Isophorone for the Synthesis of Ketoisophorone
-
The chemical synthesis of ketoisophorone, a valuable building block of vitamins and pharmaceuticals, suffers from several drawbacks in terms of reaction conditions and selectivity. Herein, the first biocatalytic one-pot double oxidation of the readily available α-isophorone to ketoisophorone is described. Variants of the self-sufficient P450cam-RhFRed with improved activity have been identified to perform the first step of the designed cascade (regio- and enantioselective allylic oxidation of α-isophorone to 4-hydroxy-α-isophorone). For the second step, the screening of a broad panel of alcohol dehydrogenases (ADHs) led to the identification of Cm-ADH10 from Candida magnoliae. The crystal structure of Cm-ADH10 was solved and docking experiments confirmed the preferred position and geometry of the substrate for catalysis. The synthesis of ketoisophorone was demonstrated both as a one-pot two-step process and as a cascade process employing designer cells co-expressing the two biocatalysts, with a productivity of up to 1.4 g L?1 d?1.
- Tavanti, Michele,Parmeggiani, Fabio,Castellanos, J. Rubén Gómez,Mattevi, Andrea,Turner, Nicholas J.
-
p. 3338 - 3348
(2017/09/13)
-
- Selective Photooxidation Reactions using Water-Soluble Anthraquinone Photocatalysts
-
The aerobic organocatalytic oxidation of alcohols was achieved by using water-soluble sodium anthraquinone sulfonate. Under visible-light activation, this catalyst mediated the aerobic oxidation of alcohols to aldehydes and ketones. The photo-oxyfunctionalization of alkanes was also possible under these conditions.
- Zhang, Wuyuan,Gacs, Jen?,Arends, Isabel W. C. E.,Hollmann, Frank
-
p. 3821 - 3826
(2017/09/13)
-
- Two catalytic systems of l-proline/Cu(II) catalyzed allylic oxidation of olefins with tert-butyl hydroperoxide
-
The nontoxic and water-soluble l-proline combined with two different forms of copper(ii): recoverable Cu-Al hydrotalcite-like compounds (Cu-Al HTLcs) and water-soluble CuCl2, as a heterogeneous catalytic system (l-proline/Cu-Al HTLcs) and two-phase catalytic system (l-proline/CuCl2) to catalyze allylic oxidation with tert-butyl hydroperoxide. The results showed that l-proline/Cu(ii) is highly active for oxidizing isophorone (IP) into ketoisophorone (KIP). Maximum catalytic effects were afforded respectively under the optimal reaction conditions, which obtained 77.9% IP conversion with 74.3% KIP selectivity catalyzed by l-proline/Cu-Al HTLcs and 73.5% conversion with 81.6% selectivity by l-proline/CuCl2. Recycling experiments of the two catalytic systems of l-proline/Cu(ii) showed they are stable and recyclable for at least six cycles with appreciable catalytic activity. And various hydrocarbons could be smoothly transformed into corresponding ketones with satisfactory conversion and selectivity by the two catalytic systems.
- Yu, Peng,Zhou, Yin,Yang, Yingwei,Tang, Ruiren
-
p. 65403 - 65411
(2016/07/26)
-
- Novel catalytic system: N-hydroxyphthalimide/hydrotalcite-like compounds catalysing allylic carbonylation of cyclic olefins
-
N-hydroxyphthalimide (NHPI) combined with stable and recoverable transition metal-aluminium binary hydrotalcite-like compounds (M-Al HTLcs, M = Cu, Ni, Co) as an unprecedented catalytic system was demonstrated for the allylic carbonylation, as the model reaction, of cyclic olefins with tert-butyl hydroperoxide (TBHP), using isophorone (IP) to ketoisophorone (KIP). The results showed NHPI combined with Cu-Al HTLcs to be an efficient catalytic system and the influences of various reaction conditions of the catalytic reaction were optimised. A maximum IP conversion of 68.0 % with 81.8 % selectivity to KIP was afforded under the optimal reaction conditions. Experiments of repeatability and restorability showed Cu-Al HTLcs to be stable for at least five cycles without noticeable loss of catalytic activity. Expanding substrates could also be efficiently converted to the corresponding ketones under the optimised reaction conditions with appreciable yields. A plausible catalytic reaction mechanism was proposed.
- Zhou, Yin,Tang, Rui-Ren,Song, Dan
-
p. 888 - 897
(2017/02/05)
-
- Oxo-isophorone preparation through efficient catalytic oxidation of alpha-isophorone
-
The invention provides oxo-isophorone preparation through efficient catalytic oxidation of alpha-isophorone, and relates to a method for preparing oxo-isophorone through catalytic oxidation of alpha-isophorone. According to the method, under a solvent-free condition, a bi-rhodium coordination compound Rh2(esp)2 is adopted as a catalyst, and a tert-butyl peroxide aqueous hydrogen (T-HYDRO) is adopted as an oxidant to carry out catalytic oxidation of alpha-isophorone.
- -
-
Paragraph 0017; 0018
(2016/11/17)
-
- Facile fabrication of a Cu@g-C3N4 nanocatalyst and its application for the aerobic oxidations of alkylaromatics and the reduction of 4-nitrophenol
-
In this study, the preparation of a Cu@g-C3N4 nanocatalyst with highly active sites was developed in a facile precipitation method by the in situ reduction of Cu2+ adsorbed on the surface of layered graphitic carbon nitride (g-C3N4). The catalyst was characterized by FT-IR, XRD, SEM, TEM, ICP, XPS and BET, verifying that the Cu nanoparticles with a mean particle size of 35.89 nm were uniformly distributed onto the surface of g-C3N4. Alkylaromatics oxidation reactions and 4-nitrophenol reduction reactions were investigated on the Cu@g-C3N4 nanocatalyst with superior catalytic activity. The aerobic oxidation of ethylbenzene (EB) to acetophenone (AP) by tert-butyl hydroperoxide (TBHP) was conducted readily, and a conversion and selectivity of 98.8% and 94.0%, respectively, could be reached under optimal conditions. Moreover, the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) employing NaBH4 has a kinetic rate constant of 1.86 × 10-2 s-1 and an activity parameter of 1.134 s-1 mM-1 in the presence of Cu@g-C3N4, which are higher values than previous results described in the literature. Repeated cycles demonstrated the outstanding recyclability and stability of the catalyst for at least four runs without a considerable loss in catalytic activity.
- Huang, Shen,Zhao, Yukai,Tang, Ruiren
-
p. 90887 - 90896
(2016/10/07)
-
- Method for catalyzing allylic oxidation of alkene in aqueous solution
-
The invention provides a method for catalyzing allylic oxidation of alkene in an aqueous solution and relates to a method for preparing corresponding carbonyl compounds by catalyzing allylic oxidation in an aqueous solution with alkenes as substrates and soluble micromolecular organic ligand assisted metal ions as catalysts. According to the method, deionized water is taken as a solvent, soluble micromolecular N,O-ligand assisted metal ions are taken as catalysts, hexadecyl trimethyl ammonium bromide and analogues thereof are taken as phase transfer catalysts, t-butyl hydroperoxide is taken as an oxidant, alkene is subjected to catalytic oxidation, and high-selectivity carbonyl compounds are prepared. The reaction proceeds in the aqueous solution, the reaction temperature is 30-110 DEG C, the reaction time is 3-30 h, reaction conditions are mild, the catalytic efficiency is high, and the catalytic system has high practicability, has a wide use range and is easy to recycle.
- -
-
Paragraph 0008; 0009
(2016/11/09)
-
- Rh2(esp)2-catalyzed allylic and benzylic oxidations
-
The dirhodium(ii) catalyst Rh2(esp)2 allows direct solvent-free allylic and benzylic oxidations by T-HYDRO with a remarkably low catalyst loading. This method is operationally simple and scalable at ambient temperature without the use of any additives. The high catalyst stability in these reactions may be attributed to a dirhodium(ii,ii) catalyst resting state, which is less prone to decomposition.
- Wang, Yuanhua,Wang, Yi,Kuang, Yi
-
supporting information
p. 5852 - 5855
(2015/03/30)
-
- MnO2/TBHP: A Versatile and User-Friendly Combination of Reagents for the Oxidation of Allylic and Benzylic Methylene Functional Groups
-
In the presence of activated MnO2, tert-butyl hydroperoxide (TBHP) in CH2Cl2 is able to oxidize the allylic and benzylic methylene groups of different classes of compounds. I describe a one-pot oxidation protocol based on two sequential steps. In the first step, carried out at low temperature, MnO2 catalyses the oxidation of the methylene group. This is followed by a second step where reaction temperature is increased, allowing MnO2 both to catalyse the decomposition of unreacted TBHP and to oxidize allylic alcohols that could possibly be formed. The proposed oxidation procedure is generally applicable, although its efficiency, regioselectivity, and chemoselectivity are strongly dependent on the structure of the substrate. A simple and user-friendly synthetic procedure for the oxidation of allylic and benzylic methylene groups to the corresponding conjugated carbonyl derivatives is described. The proposed oxidation protocol is based on the combined use of MnO2 and tert-butyl hydroperoxide, and is generally applicable.
- Serra, Stefano
-
p. 6472 - 6478
(2015/10/19)
-
- Metal-free allylic oxidation with molecular oxygen catalyzed by g-C 3N4 and N-hydroxyphthalimide
-
Polymeric graphitic carbon nitride (g-C3N4) is a layered graphite-like nitrogen-rich material, bearing the potential ability to reductively adsorb molecular oxygen for catalytic allylic oxidation. Furthermore, N-hydroxyphthalimide (NHPI) has been recognized as an efficient catalyst for aerobic oxidation of various organic compounds under mild conditions in the presence of various co-catalysts. We present here a promising strategy for employing such nitride-rich g-C3N4 combined with NHPI to form an all-organic metal-free composite and have examined its activity for allylic oxidation with molecular oxygen as the primary terminal oxidant. In the case of allylic oxidation α-isophorone catalyzed by g-C3N4/NHPI gave priority to its corresponding carbonyl compound and epoxide. The effects of various reaction conditions on the catalytic reaction were optimized, affording 74.8 % conversion with 44.4 % selectivity of ketoisophorone at 130 C in 5 h. Repeated runs demonstrated that the catalyst was stable for at least three cycles without noticeable loss of its catalytic activity. Graphical Abstract: [Figure not available: see fulltext.]
- Liu, Guiyin,Tang, Ruiren,Wang, Zhen
-
p. 717 - 722
(2014/04/03)
-
- Co(acac)catalyzed allylic and benzylic oxidation by tert -butyl hydroperoxide
-
Various allylic and benzylic substrates were oxidized to the corresponding enones, arenealdehydes and aryl ketones in good yields with tert-butyl hydroperoxide in the presence of catalytic amounts of Co(acac)under mild conditions. The reactivity, selectivity, and scope of the reaction were investigated. Georg Thieme Verlag Stuttgart. New York.
- Han, Xiaoqiang,Zhou, Ziyuan,Wan, Chuan,Xiao, Yumei,Qin, Zhaohai
-
p. 615 - 620
(2013/03/29)
-
- Stereocontrolled first total syntheses of amarouciaxanthin A and B
-
The first total syntheses of amarouciaxanthin A and B (C40) via the stereoselective Wittig reaction of C15-allenic and C 15-acetylenic tri-n-butylphosphonium salts with the unprecedented C25-3,8-dihydroxy-5,6-epoxyapocarotenal have been completed. Oxidation of the two hydroxyl groups in the left part of the resulting condensation products followed by regioselective oxirane ring opening gave the target carotenoids.
- Yamano, Yumiko,Chary, Mahankhali Venu,Wada, Akimori
-
supporting information
p. 5310 - 5313
(2013/11/06)
-
- An efficient and mild oxidation of α-isophorone to ketoisophorone catalyzed by N-hydroxyphthalimide and copper chloride
-
N-hydroxyphthalimide (NHPI) and copper chloride (CuCl2) were first utilized for aerobic oxidation of α-isophorone (α-IP) to ketoisophorone (KIP) and the effects of co-catalysts, temperature, reaction time, solvent, amount of CuCl2 and pressure of oxygen were investigated extensively. NHPI/CuCl2 turned out to be highly efficient to this oxidation with up to 91.3% conversion and 81.0% selectivity under mild conditions. And various hydrocarbons including benzylic compounds, cycloalkene and its derivatives were also oxidized smoothly under optimized conditions. Moreover, the possible reaction mechanism was proposed and verified by FT-IR spectra.
- Chen, Lihua,Tang, Ruiren,Li, Zhongying,Liang, Shan
-
experimental part
p. 459 - 463
(2012/05/20)
-
- Visible-light-induced metal-free allylic oxidation utilizing a coupled photocatalytic system of g-C3N4 and N-hydroxy compounds
-
Graphitic carbon nitride (g-C3N4) and N-hydroxy compounds can function as a non-metal photocatalytic system to activate O 2 for the selective allylic oxidation under mild conditions, avoiding the employment of any metal derivative or organic oxidizing agents. Interestingly, the novel photocatalytic system affords a remarkably high selectivity towards the formation of aldehydes, especially in the oxidation of toluene. By combining the unique nature of g-C3N4 (surface basicity, semiconductor features, high stability) and the remarkable catalytic oxidation reactivity of nitroxyl radicals, this photocatalytic system opens up a mild and efficent access for C-H bond activation. Copyright
- Zhang, Pengfei,Wang, Yong,Yao, Jia,Wang, Congmin,Yan, Chao,Antonietti, Markus,Li, Haoran
-
experimental part
p. 1447 - 1451
(2011/08/03)
-
- Metal and solvent-free oxidation of α-isophorone to ketoisophorone by molecular oxygen
-
The metal and solvent-free oxidation of α-isophorone to ketoisophorone (KIP) using N-hydroxy phthalimide (NHPI) as the catalyst under atmospheric oxygen was studied, eliminating the isomerization process of α-isophorone to β-isophorone. The effect of co-catalyst, temperature, time, amount of NHPI, and recycling on the oxidation was investigated. The oxidation of α-isophorone proceed well without any co-catalyst under 60 °C for 10 h, which was different with the traditional oxidation of α-isophorone at high temperature. Furthermore, NHPI can be easily separated and reused with a slight loss on its activity. This aerobic oxidation process by NHPI provides a good alternative way for the industrial synthesis of KIP.
- Wang, Congmin,Wang, Guoliang,Mao, Jianyong,Yao, Zhen,Li, Haoran
-
experimental part
p. 758 - 762
(2010/07/06)
-
- Mild manganese(III) acetate catalyzed allylic oxidation: Application to simple and complex alkenes
-
Manganese(III) acetate catalyzed allylic oxidation of alkenes to the corresponding enones was investigated, showing excellent regioselectivity and chemoselectivity (functional group compatibility). Δ5-Steroids were transformed into bioactive Δ5-en-7-ones under a nitrogen atmosphere, whereas simple alkenes were converted into the corresponding enones under an oxygen atmosphere in good yields.
- Shing, Tony K. M.,Yeung, Ying-Yeung,Su, Pak L.
-
p. 3149 - 3151
(2007/10/03)
-
- Dichlororuthenium(IV) complex of meso-Tetrakis(2,6-dichlorophenyl) porphyrin: Active and robust catalyst for highly selective oxidation of arenes, Unsaturated steroids, and electron-deficient alkenes by using 2,6-dichloropyridine N-oxide
-
[RuIV(2,6-Cl2tpp)Cl2], prepared in 90% yield from the reaction of [RuVI(2,6-Cl2tpp)O2] with Me3SiCl and structurally characterized by X-ray crystallography, is markedly superior to [RuIv(tmp)Cl2], [RuIV(ttp)Cl2], and [RuII(por)(CO)] (por = 2,6-Cl2tpp, F20-tpp, F28-tpp) as a catalyst for alkene epoxidation with 2,6-Cl2pyNO (2,6Cl2tpp = meso-tetrakis(2,6-dichlorophenyl)porphyrinato dianion; tmp = meso-tetramesitylporphyrinato dianion; ttp = meso-tetrakis(p-tolyl)porphyrinato dianion; F20-tpp = meso-tetrakis(pentafluorophenyl)porphyrinato dianion; F28-tpp = 2,3,7,8,12,13,17,18-octafluoro-5,10,15,20- tetrakis(pentafluorophenyl)-porphyrinato dianion). The "[Ru IV(2,6-Cl2tpp)Cl2] + 2,6-Cl 2pyNO" protocol oxidized, under acid-free conditions, a wide variety of hydrocarbons including 1) cycloalkenes, conjugated enynes, electron-deficient alkenes (to afford epoxides), 2) arenes (to afford quinones), and 3) Δ5-unsaturated steroids, Δ4-3- ketosteroids, and estratetraene derivatives (to afford epoxide/ketone derivatives of steroids) in up to 99% product yield within several hours with up to 100% substrate conversion and excellent regio- or diastereoselectivity. Catalyst [RuIv(2,6-Cl2tpp)Cl2] is remarkably active and robust toward the above oxidation reactions, and turnover numbers of up to 6.4 × 103, 2.0 × 104, and 1.6 × 104 were obtained for the oxidation of α,β-unsaturated ketones, arenes, and Δ5-unsaturated steroids, respectively.
- Zhang, Jun-Long,Che, Chi-Ming
-
p. 3899 - 3914
(2007/10/03)
-
- β-hydroxysulfoxides as chiral cyclic ketone equivalents: Enantioselective synthesis of polysubstituted cyclohexanones, cyclohexenones and cyclohexenediones
-
The β-hydroxysulfoxide moiety, after oxidation to sulfone, acts as a masked carbonyl group in a cyclic system, opening an easy access to differently substituted enantiomerically pure cyclic ketones by means of aluminium-mediated conjugate additions, stereoselective reductions and elimination by retrocondensation in basic medium.
- Carreno, M. Carmen,Perez-Gonzalez, Manuel,Ribagorda, Maria,Somoza, Alvaro,Urbano, Antonio
-
p. 3052 - 3053
(2007/10/03)
-
- Precursors for fragrant ketones and fragrant aldehydes
-
The present invention refers to fragrance precursors of formula I for a fragrant ketone of formula II and one or more fragrant aldehydes or ketones of formula III and IV, These fragrance precursors are useful in perfumery, especially in the fine and functional perfumery.
- -
-
-
- Process and apparatus for producing ketoisophorone
-
β-isophorone is formed by isomerizing α-isophorone in the presence of an isomerizing catalyst (an aliphatic C5-20 polycarboxylic acid) in an isomerizing-reaction unit 1. The β-isophorone thus formed is oxidized with oxygen in an inert solvent in the presence of an oxidizing catalyst (a complex salt of a transition metal and an N,N'-disalicylidenediamine) in an oxidizing-reaction unit 2, thereby forming ketoisophorone. After removing a low-boiling point component, which is an impurity (non-conjugated cyclic ketone), from the reaction mixture using a distilling unit 3, a high-boiling component (oxidizing catalyst) is separated in a distilling unit 4, and then ketoisophorone is separated from the solvent in the separation unit 5. Thereafter, the solvent containing 0 to 5,000 ppm (weight basis) of the impurities and substantially free from ketoisophorone is recycled to the oxidizing reaction through a recycling line 6. According to the present invention, the combination of the isomerizing reaction and the oxidizing reaction makes it possible to produce ketoisophorone from α-isophorone while maintaining the activity of the oxydizing catalyst.
- -
-
Page column 15-17
(2008/06/13)
-
- Ketone precursors for organoleptic compounds
-
The invention discloses ketones of formula I: wherein, Y is an optionally substituted alkyl, cycloalkyl, or cycloalkylalkyl, wherein each alkyl group is straight or branched and each alkyl and cycloalkyl group is saturated or unsaturated; R1is hydrogen or a C1-6alkyl group that is substituted, saturated or unsaturated, straight or branched; A is a chromophoric substituted aromatic ring or ring system; n is an integer; and with the proviso that formula I is not 2-ethoxy-1-phenyl-ethanone. These compositions are useful for the delivery of organoleptic compounds, especially of flavors, fragrances, masking agents and antimicrobial compounds.
- -
-
-
- Oxidation of β,γ-unsaturated ketones with molecular oxygen catalyzed by metal phthalocyanines and porphyrins: A pratical synthesis of oxophorone
-
Oxidation of 3,5,5-trimethylcyclohex-3-en-1-one (1) with molecular oxygen catalyzed by metal phthalocyanines (Pc) and 5,10,15,20-tetraphenylporphyrins (TPP) including Mn(II), Mn(III), Fe(II), Fe(III), Co(II), Cu(II), and Ru(II) to 3,5,5-trimethylcyclohex-2-ene-1,4-dione (2) was studied. TPPMn(III)Cl showed an excellent catalytic activity, affording 2 in 93percent yield and 12500 turnover number.
- Ito, Nobuhiko,Etoh, Takeaki,Hagiwara, Hisahiro,Kato, Michiharu
-
p. 153 - 155
(2007/10/03)
-
- Electrochemical Epoxidation of Electron-Poor Olefins Using Silver Bipyridine Based Redox Mediators
-
Electrogenerated and regenerated silver(III)oxo bis(2,2'-bipyridine) and similar complexes can act as redox catalysts for the indirect electrochemical epoxidation of electron-deficient olefins in aqueous acetonitrile.Thus, isobutyl methacrylate is electrolyzed to form the epoxide with 87percent material yield and 21percent current yield.
- Kandzia, Christof,Steckhan, Eberhard
-
p. 3695 - 3698
(2007/10/02)
-
- Cycloalkylidene dyes
-
Cycloalkylidene dyes have the formula STR1 where m is 0 or 1, L is a chemical bond or C1 -C2 -alkylene, which may be substituted, R1 is hydrogen, C1 -C20 -alkyl, which may be phenyl-substituted, substituted or unsubstituted phenyl, naphthyl or C3 -C7 -cycloalkyl, Y is oxygen or two hydrogens, X1 is oxygen and X2 is C1 -C8 -alkanoyloxy, substituted or unsubstituted benzoyloxy, C1 -C6 -trialkylsilyloxy or a radical of the formula OR1 or NR2 R3, where R1 is as defined above and R2 and R3 are identical or different and each is independently of the other C1 -C20 -alkyl, which may be phenyl-substituted, substituted or unsubstituted phenyl, naphthyl, or C3 -C7 -cycloalkyl or R2 and R3 together with the nitrogen atom joining them are saturated heterocyclyl, or else one of R2 and R3 is hydrogen, or X1 and X2 together are a radical of the formula STR2 where Z is oxygen, sulfur or NR2, where R2 is as defined above, and Q is a carbocyclic or heterocyclic ring in which the substituents N and Z occupy adjacent positions.
- -
-
-
- Norisoprenoids in Vitis vinifera White Wine Grapes and the Identification of a Precursor of Damascenone in These Fruits
-
Twenty-four norisoprenoids, which are either free volatile components of juices of Vitis vinifera cvv.Chardonnay, Semillon and Sauvignon Blanc, or are liberated by glycosidase enzyme, or acid hydrolysis of extracts of these juices, have been identified.Eleven of these norisoprenoids are reported as grape products for the first time.The hypothetical 7-oxomegastigmane precursors, grasshopper ketone (5) and megastigm-5-en-7-yne-3,9-diol (10), as well as the related allene, 9-hydroxymegastigma-4,6,7-trien-3-one (6), have been observed for the first time, cooccurring with damascenone (1), 3-hydroxy-β-damascone (2), 3-oxo-β-damascone (3) and 3-oxo-α-damascone (4).Hydrolytic studies have shown that megastigm-5-en-7-yne-3,9-diol (10) is a precursor of damascenone (1) and 3-hydroxy-β-damascone (2) during wine conservation.
- Sefton, Mark A.,Skouroumounis, George K.,Massy-Westropp, Ralph A.,Williams, Patrick J.
-
p. 2071 - 2084
(2007/10/02)
-
- 3-OXO-α-IONOL, VOMIFOLIOL AND ROSEOSIDE IN VITIS VINIFERA FRUIT
-
Key Word Index - Vitis vinifera; Vitaceae; grapes; 3-oxo-α-ionol; vomifoliol; dehydrovomifoliol; roseoside; hydrolytic studies. 3-Oxo-α-ionol, vomifoliol and dehydrovomifoliol were identified for the first time in fruit from Vitis vinifera.The last named compound was mainly present free in the juice while the others existed predominantly as conjugates.In the case of vomifoliol, the conjugation was with glucose, i.e. as roseoside.Hydrolytic studies on 3-oxo-α-ionol and vomifoliol gave a range of compounds which have been recognized as fruit and plant products.
- Strauss, Christopher R.,Wilson, Bevan,Williams, Patrick J.
-
p. 1995 - 1998
(2007/10/02)
-
- SYNTHESIS OF CEDRANOID SESQUITERPENES. III. FUNCTIONALIZATION AT CARBON 4
-
Dimethyl 6,6-dimethyl-5,7-dioxobicyclooct-2-ene-2,3-dicarboxylate (8) on irradiation in acetophenone gives dimethyl 6,6-dimethyl-4,7-dioxotricyclo2,8>octane-1,8-dicarboxylate (13), which on treatment with lithium dimethyl cuprate followed by monodecarbomethoxylation gives methyl 4,4-endo-8-trimethyl-3,6-dioxo-cis-bicyclooctane-1-carboxylate (17).Similar irradiation of dimethyl 4,6,6-trimethyl-5,7-dioxobicyclooct-2-ene-2,3-dicarboxylate (24) and its 7,7-ethylenedioxy derivative (25) followed by treatment with DBU and concentrated H2SO4, respectively, gives dimethyl 3-hydroxy-4,4,8-trimethyl-6-oxo-cis-bicyclo-octa-2,7-diene-1,2-dicarboxylate (30).This, on acetylation, reduction with NaBH4/CeCl3, methanolysis, monodecarbomethoxylation, and hydrogenation, gives methyl endo-6-hydroxy-4,4-endo-8-trimethyl-3-oxo-cis-bicyclooctane-1-carboxylate (38), while on reduction with Li/NH3 followed by monodecarbomethoxylation it gives a methyl 6-hydroxy-4,4-exo-8-trimethyl-3-oxo-cis-bicyclooctane-1-carboxylate (33).
- Yates, Peter,Burnell, D. Jean,Freer, Vernon J.,Sawyer, Jeffery F.
-
-
- The Vinylogous Tricarbonyl Chromophore. Violerythrine End Groups and Related Six-Membered Ring Compounds. Their Synthesis, Conformation, and Investigation by Photoelectron, UV, and NMR Spectroscopy and by Crystal Structure Analysis
-
The synthesis of five- and six-membered rings 3a, 4, 5b, 5c, and 17a, containing the structural moiety 3-pentene-1,2,5-trione, is described.The chromophoric properties of these vinylogous tricarbonyls together with related compounds are investigated.The conformation in solution, particularly the torsion angle ring/sidechain, can be derived from measurements of 3JCH coupling constants, NOE difference spectra, and force-field calculations.X-ray structure analyses of 11a, 17a, 18a, and 35 afford geometries in the solid state.Ionization energies are determined by means of photoelectron spectroscopy.The theoretical calculations and interpretation of absorption spectra and colour are carried out using the models CNDO/S-CI and HAM/3.
- Martin, Hans-Dieter,Kummer, Matthias,Martin, Georg,Bartsch, Juergen,Brueck, Dieter,et al.
-
p. 1133 - 1150
(2007/10/02)
-
- THE OXYGENATION OF α-ISOPHORONE AND ITS SILYL ENOL ETHER WITH t-BuOOH IN THE PRESENCE OF METAL CATALYSTS
-
Treatment of α-isophorone (1) with t-BuOOH in the presence of palladium(II) or copper(I) catalyst gives ketoisophorone (2) selectively.A similar treatment of silyl enol ether 7 derived from 1 affords 6-hydroxylisophorone 8.
- Hosokawa, Takahiro,Inui, Shiro,Murahashi, Shun-Ichi
-
p. 1081 - 1082
(2007/10/02)
-
- Process for the oxidation of β-isophorone
-
A process for the oxidation of β-ethylenically unsaturated ketones, especially β-isophorone, is provided whereby the ketone is oxidized with a source of molecular oxygen in an organic liquid solvent in the presence of a base and certain chelate catalysts of cobalt or manganese as defined.
- -
-
-