- Oxidation of alkyl aromatics to ketones by tert-butyl hydroperoxide on manganese dioxide catalyst
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The catalytic activity of the manganese oxide was investigated for the oxidative functionalization of alkylaromatics to benzylic ketones using tert-butyl hydroperoxide (TBHP) as an oxidant. Manganese oxides of different types were tested for this reaction. Of all the oxides, the nano amorphous manganese dioxide exhibited significant catalytic activity and selectivity for the reaction. The nano amorphous MnO2/TBHP catalytic system could also be reused for six consecutive cycles with no considerable loss in catalytic activity.
- Burange, Anand S.,Kale, Sandip R.,Jayaram, Radha V.
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- The electron as a protecting group. 3. Generation of acenaphthyne radical anion and the determination of the heat of formation of a strained cycloalkyne
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Acenaphthyne dicarboxylate (12) was transferred into the gas phase from solution via electrospray ionization and subsequently was sequentially fragmented in a Fourier transform mass spectrometer to afford acenaphthyne radical anion (9). Structural confirmation of 9 was achieved by converting it to acenaphthenone enolate (13) and demonstrating that this species is identical to the ion produced upon deprotonation of acenaphthenone (5). The reactivity of 9 was explored, and since an electron can serve as a protecting group, we were able to measure the heat of hydrogenation (98 ± 4 kcal mol-1) and the heat of formation (160 ± 4 kcal mol-l) of acenaphthyne (1) via the application of a thermodynamic cycle. Its strain energy (68 kcal mol-1) and acenaphthylene's (10H) first and second C-H bond dissociation energies (117 ± 4 and 84 ± 2 kcal mol-1) also were obtained. Ab initio and density functional theory calculations were carried out on the species of interest to explore their geometries and energetics. Our results were interpreted in comparison to cyclopentyne, and its predicted heat of formation (98 kcal mol-l) and strain energy (59 kcal mol-1) are reported.
- Broadus,Kass
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- Decomposition of acenaphthylene by ultrasonic irradiation
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Polycyclic aromatic hydrocarbons were extracted from a soil sample using ultrasound and dichloromethane-, cyclohexane-, and toluene-water mixtures. It was found that when dichloromethane is used as an extractant, acenaphthylene reacts with the solvent Several chlorinated and oxygenated derivatives were identified. The results show that chlorinated solvents should be avoided because of their sonolytic decomposition. Particularly unsaturated nonaromatic compounds might react with intermediate decomposition radicals of the solvent
- Leonhardt,Stahl
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- Conjugated Biradical Intermediates: Spectroscopic, Kinetic, and Trapping Studies of 2,2-Dimethyl-1,3-perinaphthadiyl
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The biradical 2,2-dimethyl-1,3-perinaphthadiyl (a) was generated from different precursors, the naphthocyclopropane 1 and the azo copound 2, and from each by three different pathways (pyrolysis, direct photolysis, and triplet sensitization, Scheme 1).The combined evidence from flash photolysis, low-temperature spectroscopy, and product analyses provides a detailed mechanistic picture of the formation and decay of this reactive intermediate which is persistent at 77 K in the triplet ground state (3a) and rather long-lived (400 μs) at room temperature.When formed in its lowest singlet state (1a), the biradical is too short-lived to undergo intersystem crossing to 3a or bimolecular reactions.Thus, 3a is formed exclusively from the excited triplet state of the precursor compounds, 31* or 32*.The monomolecular decay of 3a is retarded by the spin barrier; 3a initiates the polymerization of acrylonitrile and is trapped by 3O2.
- Hasler, Erich,Gassmann, Ernst,Wirz, Jacob
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- Highly selective oxidation of tetralin to 1-tetralone over mesoporous CrMCM-41 molecular sieve catalyst using supercritical carbon dioxide
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Selective oxidation of tetralin by molecular oxygen over mesoporous CrMCM-41 molecular sieve catalyst using supercritical carbon dioxide (scCO 2) solvent has been investigated. CrMCM-41 catalyst gave high selectivity (96.2%) and good yield (63.4%) of 1-tetralone. The presence of scCO2 medium improves 1-tetralone selectivity and suppresses leaching of chromium from the CrMCM-41. The activity over recycled CrMCM-41 remains nearly the same under the present experimental conditions. The effect of the reaction parameters on CrMCM-41 was also studied in detail along with comparison of its catalytic activities with other mesoporous catalysts, viz. MnMCM-41, CoMCM-41, microporous CrAPO-5, CoMFI, and macroporous Cr/SiO2 catalyst, respectively. In addition this catalytic system was also applied for the oxidation of other benzylic compounds such as indane, fluorene, acenaphthene and diphenylmethane. The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2009.
- Dapurkar, Sudhir E.,Kawanami, Hajime,Yokoyama, Toshirou,Ikushima, Yutaka
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- Polyethylene glycol radical-initiated benzylic C-H bond oxygenation in compressed carbon dioxide
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The PEG radical originating from the thermal/oxidative degradation of PEG in dense CO2 was successfully applied to the oxygenation of benzylic hydrocarbons under organic solvent-free conditions. In addition, in our study, dense CO2 could improve the oxygenation reaction.
- Wang, Jin-Quan,He, Liang-Nian
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- High-efficient metal-free aerobic oxidation of aromatic hydrocarbons by N, N-dihydroxypyromellitimide and 1,4-diamino-2,3-dichloroanthraquinone
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Metal-free organic catalytic system combining with N, N-dihydroxypyromellitimide (NDHPI) and 1,4-diamino-2,3-dichloroanthraquinone (DADCAQ) was developed for the selective oxidation of hydrocarbon. Being able to simultaneously show good catalytic activity for the oxidation of hydrocarbon and alcohol, NDHPI/DADCAQ was found to be efficient for the conversion of hydrocarbon to ketone. In addition, due to its specific molecular structure, NDHPI was found to be more stable and could supply a PIDNO (pyromellitimide N, N-dioxyl free radical) during the catalytic process. So, higher catalytic activity could be obtained than the famous NHPI even with only half usage, which resolved the problem of high usage (usually 10 mol%) for the organic N-OH compounds to some extent. With 5 mol% NDHPI and 1.25 mol% DADCAQ being used under the conditions of 110 °C and 0.3 MPa molecular oxygen for 7 h, high conversion of ethylbenzene (89.6%), tetralin (98.8%), indene (96.9%), and inert toluene (50.7%) could be selectively converted to the products of acetophenone (93.4%), α-tetralone (97.3%), 1-indanone (98.9%), and benzoic acid (92.4%), respectively.
- Chen, Chen,Lv, Zhenguo,Wang, Huibin,Yang, Yuanyuan,Ye, Yicheng,Zhang, Qiaohong,Zhu, Zhuwei
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- V2O5@TiO2 Catalyzed Green and Selective Oxidation of Alcohols, Alkylbenzenes and Styrenes to Carbonyls
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The versatile application of different functional groups such as alcohols (1° and 2°), alkyl arenes, and (aryl)olefins to construct carbon-oxygen bond via oxidation is an area of intense research. Here, we report a reusable heterogeneous V2O5@TiO2 catalyzed selective oxidation of various functionalities utilizing different mild and eco-compatible oxidants under greener reaction conditions. The method was successfully applied for the alcohol oxidation, oxidative scission of styrenes, and benzylic C?H oxidation to their corresponding aldehydes and ketones. The utilization of mild and eco-friendly oxidizing reagents such as K2S2O8, H2O2 (30 % aq.), TBHP (70 % aq.), broad substrate scope, gram-scale synthesis, and catalyst recyclability are notable features of the developed protocol.
- Upadhyay, Rahul,Kumar, Shashi,Maurya, Sushil K.
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p. 3594 - 3600
(2021/07/02)
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- Selective electrochemical oxidation of aromatic hydrocarbons and preparation of mono/multi-carbonyl compounds
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A selective electrochemical oxidation was developed under mild condition. Various mono-carbonyl and multi-carbonyl compounds can be prepared from different aromatic hydrocarbons with moderate to excellent yield and selectivity by virtue of this electrochemical oxidation. The produced carbonyl compounds can be further transformed into α-ketoamides, homoallylic alcohols and oximes in a one-pot reaction. In particular, a series of α-ketoamides were prepared in a one-pot continuous electrolysis. Mechanistic studies showed that 2,2,2-trifluoroethan-1-ol (TFE) can interact with catalyst species and generate the corresponding hydrogen-bonding complex to enhance the electrochemical oxidation performance. [Figure not available: see fulltext.]
- Li, Zhibin,Zhang, Yan,Li, Kuiliang,Zhou, Zhenghong,Zha, Zhenggen,Wang, Zhiyong
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p. 2134 - 2141
(2021/09/29)
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- Synthesis of novel fused acenaphtopyrimidine hybrid, its photophysical properties and HSA interaction
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A facile and versatile procedure for the synthesis of novel functionalised 10-(1H-indol-3-yl)acenaphtho[1,2-d]pyrimidin-8-amine (compound 4) has been described. The novel intermediate enone (3) and pyrimidine derivatives (4) were characterised by using FT-IR, NMR and MS. Moreover, the photophysical properties of compound 4 and its interaction with HSA (Human Serum Albumin) have been investigated by means of photometric and fluorimetric titration. Compound 4 showed the increase in fluorescence and hypsochromic shift of its maximum upon the addition of HSA that interaction is supported by molecular docking. Overall, Compound 4 has promising affinity towards HSA which was not previously reported for any fused acenaphtenone–pyrimidine hybrid analogues.
- Yal??n, Ergin
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- Propargylamine-selective dual fluorescence turn-on method for post-synthetic labeling of DNA
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We have developed a propargylamine-selective dual fluorescence turn-on system, using ylidenemalononitrile enamines, for post-synthetic DNA labeling, allowing the direct monitoring of DNA using dual emission in living cells.
- Nguyen, Van Thang,Pandith, Anup,Seo, Young Jun
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supporting information
p. 3199 - 3202
(2020/03/23)
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- Ruthenium-Catalyzed Dehydrogenation of Alcohols with Carbodiimide via a Hydrogen Transfer Mechanism
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Ruthenium-catalyzed oxidative dehydrogenation of alcohols using carbodiimide as an efficient hydrogen acceptor has been developed. The protocol exhibits wide substrate scope with good to excellent yields. The results of the kinetic analysis indicated that the reaction mechanism includes the hydrogen transfer process and that the addition of carbodiimide is essential for the reaction system, and the resulting amidine also could react as a hydrogen acceptor.
- Sueki, Shunsuke,Matsuyama, Mizuki,Watanabe, Azumi,Kanemaki, Arata,Katakawa, Kazuaki,Anada, Masahiro
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p. 4878 - 4885
(2020/06/02)
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- Palladium-catalyzed expedient Heck annulations in 1-bromo-1,5-dien-3-ols: Exceptional formation of fused bicycles
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An unprecedented Pd-catalyzed intramolecular Heck cyclization has been investigated on halogenated diene scaffolds undergoing various mode of cyclization and termination leading to the formation of structurally differing fused cyclopenta(e)none and aromatic analogue. The discrimination in the fate of palladium intermediates formed in situ undergoing Heck cyclization preferentially arises out of the difference in reaction temperature as well as substrate architecture. Sequential Heck reaction of 1-Bromo-5-methyl-1-aryl-hexa-1,5-dien-3-ol derivatives followed by oxidation or termination via sp2 C–]H activation in aromatic ring led to the formation of fused cyclopentanes. However, the similar reaction at elevated temperature showed predominance towards the formation of aromatic analogues via one pot cyclization and dehydroxylation. The mechanism for the formation of cyclopentanone fused with cyclopropane ring system is supported by density functional theory based calculations.
- Ray, Jayanta K.,Singha, Raju,Ray, Devalina,Ray, Paramita,Rao, Davuluri Yogeswara,Anoop, Anakuthil
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supporting information
p. 931 - 935
(2019/03/04)
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- Metal iridium or platinum complex and organic electroluminescent device comprising metal iridium or platinum complex
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The invention discloses a metal iridium or platinum complex and an organic electroluminescent device comprising the metal iridium or platinum complex. A structural formula of the metal iridium or platinum complex is as shown in structural formula I shown in the description. The organic electroluminescent device emits deeply blue to green light, and is high in light-emitting efficiency; meanwhile,the material is good in thermal stability, is easy to prepare, is easy to purify, and is an ideal choice of a light-emitting material of the organic electroluminescent device.
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Paragraph 0098; 0099; 0100
(2018/04/03)
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- Organic iridium-containing metal complex and organic light-emitting device thereof
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The invention discloses an organic iridium-containing metal complex and an organic light-emitting device thereof, and relates to the technical field of organic photoelectric materials. An electron-rich bis-nitrogen coordination structure in a complex structure is favorable for stabilizing a central trivalent iridium ion, a ligand of the bis-nitrogen coordination structure and a quaternary ring composed of metal have stronger rigidity, so that higher chemical stability and thermal stability are obtained, and the luminous efficiency of the complex is improved. The synthesis is simple and easy tooperate, and the organic iridium-containing metal complex can be applied to the organic light-emitting device as a light-emitting layer doped material, and can effectively solve problems of low luminous efficiency and high driving voltage in the organic light-emitting device. The iridium complex is prepared into a device, especially as a doped material, and the device exhibits the advantages of low driving voltage and high luminous efficiency, and is superior to existing OLED devices.
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Paragraph 0069; 0071
(2018/11/03)
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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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- Remarkable Ability of the Benzylidene Ligand To Control Initiation of Hoveyda–Grubbs Metathesis Catalysts
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The structure of the chelating benzylidene ligand offers the unique ability to control the initiation of Hoveyda–Grubbs metathesis catalysts. Apart from steric and electronic effects acting on the step involving opening of the chelate ring, changes related to the following ligand-exchange process may also play a critical role. Our mechanistic model reveals that ligands substituted at the 6-position of the benzylidene ring enter the metathesis cycle in a nonoptimal chelating conformation, and thus the coordination number of the ruthenium center transiently increases to six (associative mechanism). In effect, the synthesis and initiation of the catalysts becomes difficult, and the energy barrier of the ligand-exchange process is controlled by the structure of the coordinating OR group. Moreover, we explain how isomeric naphthalene ligands affect the catalytic performance by an indivisible combination of steric and π-electron delocalization effects.
- Basak, Tymoteusz,Grudzień, Krzysztof,Barbasiewicz, Micha?
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supporting information
p. 3513 - 3523
(2016/07/29)
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- Identification of (S)-selective transaminases for the asymmetric synthesis of bulky chiral amines
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The use of transaminases to access pharmaceutically relevant chiral amines is an attractive alternative to transition-metal-catalysed asymmetric chemical synthesis. However, one major challenge is their limited substrate scope. Here we report the creation of highly active and stereoselective transaminases starting from fold class I. The transaminases were developed by extensive protein engineering followed by optimization of the identified motif. The resulting enzymes exhibited up to 8,900-fold higher activity than the starting scaffold and are highly stereoselective (up to >99.9% enantiomeric excess) in the asymmetric synthesis of a set of chiral amines bearing bulky substituents. These enzymes should therefore be suitable for use in the synthesis of a wide array of potential intermediates for pharmaceuticals. We also show that the motif can be engineered into other protein scaffolds with sequence identities as low as 70%, and as such should have a broad impact in the field of biocatalytic synthesis and enzyme engineering.
- Pavlidis, Ioannis V.,Wei?, Martin S.,Genz, Maika,Spurr, Paul,Hanlon, Steven P.,Wirz, Beat,Iding, Hans,Bornscheuer, Uwe T.
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p. 1076 - 1082
(2016/11/02)
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- Characterization of hamster NAD+-dependent 3(17)β-hydroxysteroid dehydrogenase belonging to the aldo-keto reductase 1C subfamily
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The cDNAs for morphine 6-dehydrogenase (AKR1C34) and its homologous aldo-keto reductase (AKR1C35) were cloned from golden hamster liver, and their enzymatic properties and tissue distribution were compared. AKR1C34 and AKR1C35 similarly oxidized various xenobiotic alicyclic alcohols using NAD+, but differed in their substrate specificity for hydroxysteroids and inhibitor sensitivity. While AKR1C34 showed 3α/17β/20α-hydroxysteroid dehydrogenase activities, AKR1C35 efficiently oxidized various 3β- and 17β-hydroxysteroids, including biologically active 3β-hydroxy-5α/β-dihydro-C19/C21-steroids, dehydroepiandrosterone and 17β-estradiol. AKR1C35 also differed from AKR1C34 in its high sensitivity to flavonoids, which inhibited competitively with respect to 17β-estradiol (Ki 0.11-0.69 μM). The mRNA for AKR1C35 was expressed liver-specific in male hamsters and ubiquitously in female hamsters, whereas the expression of the mRNA for AKR1C34 displayed opposite sexual dimorphism. Because AKR1C35 is the first 3(17)β-hydroxysteroid dehydrogenase in the AKR superfamily, we also investigated the molecular determinants for the 3β-hydroxysteroid dehydrogenase activity by replacement of Val54 and Cys310 in AKR1C35 with the corresponding residues in AKR1C34, Ala and Phe, respectively. The mutation of Val54Ala, but not Cys310Phe, significantly impaired this activity, suggesting that Val54 plays a critical role in recognition of the steroidal substrate.
- Endo, Satoshi,Noda, Misato,Ikari, Akira,Tatematsu, Kenjiro,El-Kabbani, Ossama,Hara, Akira,Kitade, Yukio,Matsunaga, Toshiyuki
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p. 425 - 434
(2015/11/27)
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- Fabrication of CuCr2O4 spinel nanoparticles: A potential catalyst for the selective oxidation of cycloalkanes via activation of Csp3-H bond
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We report here preparation of CuCr2O4 spinel nanoparticle catalyst, mediated by cationic surfactant CTAB in hydrothermal route. XRD revealed the formation of CuCr2O4 spinel phase and TEM showed the particle size of 30-60 nm. The catalyst was speculated to be highly active for selective oxidation of cyclohexane to cyclohexanone with H2O2. A cyclohexane conversion of 70% with 85% cyclohexanone selectivity was achieved over this catalyst at 50 °C temperature. Moreover, the catalyst did not show any significant activity loss even after 8 reuses and proved its efficacy in the oxidation of other cycloalkanes also.
- Acharyya, Shankha S.,Ghosh, Shilpi,Adak, Shubhadeep,Tripathi, Deependra,Bal, Rajaram
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p. 145 - 150
(2015/01/09)
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- Ylidenemalononitrile enamines as fluorescent "turn-on" indicators for primary amines
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Ylidenemalononitrile enamines undergo rapid amine exchange followed by a cyclization with primary amines to yield fluorescent products with emission intensities as high as 900 times greater than the starting materials. After identifying the fluorescent species by X-ray crystallography, we demonstrate that the rate of amine exchange is substrate dependent and that by simple structural variation the fluorescence can be tuned over the entire visible spectrum. We further demonstrate their potential application in biomolecule labeling.
- Longstreet, Ashley R.,Jo, Minyoung,Chandler, Rebecca R.,Hanson, Kenneth,Zhan, Naiqian,Hrudka, Jeremy J.,Mattoussi, Hedi,Shatruk, Michael,McQuade, D. Tyler
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supporting information
p. 15493 - 15496
(2015/01/08)
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- HETEROCYCLIC COMPOUNDS AND METHODS OF USE THEREOF
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Provided herein are heterocyclyl compounds, methods of their synthesis, pharmaceutical compositions comprising the compounds, and methods of their use. The compounds provided herein are useful for the treatment, prevention, and/or management of various neurological disorders, including but not limited to, psychosis and schizophrenia.
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Paragraph 00374
(2014/07/21)
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- Synthesis of a reusable polymer anchored cobalt(II) complex for the aerobic oxidation of alkyl aromatics and unsaturated organic compounds
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Polymer anchored cobalt(II) catalyst was synthesized and characterized. The solid catalyst was characterized by fourier transform infrared spectroscopy (FT-IR), UV-vis diffuse reflectance spectroscopy (DRS), thermogravimetric analysis (TGA) and scanning electron microscope (SEM). The catalytic activity of the complex was investigated for the oxidative functionalization of alkyl aromatics to benzylic ketones using O2 (1 atm) with 1 mmol H2O2. The oxidation of organic compounds with carbon-carbon double bond with molecular oxygen under atmospheric pressure in the presence of this catalyst has also been studied. Oxidation of alkenes, cycloalkenes and terpenes gave corresponding epoxy derivatives. The developed catalyst can be facilely recovered and reused six times without significant decrease in its activity and selectivity.
- Islam, Sk Manirul,Ghosh, Kajari,Molla, Rostam Ali,Roy, Anupam Singha,Salam, Noor,Iqubal, Md Asif
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- Kinetic studies of acenaphthene oxidation catalyzed by N-Hydroxyphthalimide
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The acenaphthene oxidation with molecular oxygen in the presence of N-hydroxyphthalimide (NHPI) has been investigated. It is shown that the main oxidation product is acenaphthene hydroperoxide. The phthalimide-N-oxyl (PINO) radical has been generated in situ from its hydroxyimide parent, NHPI, by oxidation with iodobenzenediacetate. The rate constant of H-abstraction (k H) from acenaphthene by PINO has been determined spectroscopically in acetonitrile. The kinetic isotope effect and the activation parameters have also been measured. On the basis of the results of our studies and available published literature data, a plausible mechanism for the oxidation process of acenaphthene with dioxygen catalyzed by NHPI was discussed.
- Opeida,Litvinov,Kushch,Kompanets,Shendrik
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p. 515 - 524
(2013/07/26)
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- Rabbit 3-hydroxyhexobarbital dehydrogenase is a NADPH-preferring reductase with broad substrate specificity for ketosteroids, prostaglandin D2, and other endogenous and xenobiotic carbonyl compounds
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3-Hydroxyhexobarbital dehydrogenase (3HBD) catalyzes NAD(P) +-linked oxidation of 3-hydroxyhexobarbital into 3-oxohexobarbital. The enzyme has been thought to act as a dehydrogenase for xenobiotic alcohols and some hydroxysteroids, but its physiological function remains unknown. We have purified rabbit 3HBD, isolated its cDNA, and examined its specificity for coenzymes and substrates, reaction directionality and tissue distribution. 3HBD is a member (AKR1C29) of the aldo-keto reductase (AKR) superfamily, and exhibited high preference for NADP(H) over NAD(H) at a physiological pH of 7.4. In the NADPH-linked reduction, 3HBD showed broad substrate specificity for a variety of quinones, ketones and aldehydes, including 3-, 17- and 20-ketosteroids and prostaglandin D2, which were converted to 3α-, 17β- and 20α-hydroxysteroids and 9α,11β- prostaglandin F2, respectively. Especially, α-diketones (such as isatin and diacetyl) and lipid peroxidation-derived aldehydes (such as 4-oxo- and 4-hydroxy-2-nonenals) were excellent substrates showing low Km values (0.1-5.9 μM). In 3HBD-overexpressed cells, 3-oxohexobarbital and 5β-androstan-3α-ol-17-one were metabolized into 3-hydroxyhexobarbital and 5β-androstane-3α,17β-diol, respectively, but the reverse reactions did not proceed. The overexpression of the enzyme in the cells decreased the cytotoxicity of 4-oxo-2-nonenal. The mRNA for 3HBD was ubiquitously expressed in rabbit tissues. The results suggest that 3HBD is an NADPH-preferring reductase, and plays roles in the metabolisms of steroids, prostaglandin D2, carbohydrates and xenobiotics, as well as a defense system, protecting against reactive carbonyl compounds.
- Endo, Satoshi,Matsunaga, Toshiyuki,Matsumoto, Atsuko,Arai, Yuki,Ohno, Satoshi,El-Kabbani, Ossama,Tajima, Kazuo,Bunai, Yasuo,Yamano, Shigeru,Hara, Akira,Kitade, Yukio
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p. 1366 - 1375
(2013/11/19)
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- Hyperaromatic stabilization of arenium ions: A remarkable cis stereoselectivity of nucleophilic trapping of β-hydroxyarenium ions by water
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Cis- and trans-1,2-dihydrodiol isomers of benzene undergo acid-catalyzed dehydration to form phenol. In principle the isomeric substrates react through a common β-hydroxybenzenium (cyclohexadienyl) carbocation. Notwithstanding, the isomers show a large difference in reactivity, kcis/k trans = 4500. This difference is reduced to kcis/k trans = 440 and 50 for the 1,2-dihydrodiols of naphthalene and 9,10-dihydrodiols of phenanthrene, respectively, and to 6.9 for the dihydrodiols of the nonaromatic 7,8-double bond of acenaphthylene. Because the difference in stabilities of cis- and trans-dihydrodiols should be no more than 2-3-fold, these results imply a high cis stereoselectivity for nucleophilic trapping of a β-hydroxyarenium cation by water in the reverse of the carbocation-forming reaction. This is confirmed by studies of the 10-hydroxy-9-phenanthrenium ion generated from aqueous solvolyses of the trans-9,10-bromohydrin derivative of phenanthrene and the monotrichloroacetate ester of the phenanthrene cis-9,10-dihydrodiol. The cis stereoselectivity of forward and reverse reactions is explained by the formation (in the "forward" reaction) of different conformations of carbocation from cis- and trans-dihydrodiol reactants with respectively β-C-H and β-C-OH bonds in pseudoaxial positions with respect to the charge center of the carbocation optimal for hyperconjugation. Formation of different conformations is constrained by departure of the (protonated) OH leaving group from a pseudoaxial position. The difference in stability of the carbocations is suggested to stem (a) from the greater hyperconjugative ability of a C-H than a C-OH bond and (b) from enhanced conjugation arising from the stabilizing influence of an aromatic ring in the no-bond resonance structures representing the hyperconjugation (C 6H6OH+ ? C6H5OH H+). This is consistent with an earlier suggestion by Mulliken and a demonstration by Schleyer that the benzenium ion is subject to hyperconjugative aromatic stabilization. It is proposed that, in analogy with the terms homoconjugation and homoaromaticity, arenium ions should be considered as "hyperaromatic".
- Lawlor, David A.,Kudavalli, Jaya Satyanarayana,MacCormac, Aoife C.,Coyne, Dara A.,Boyd, Derek R.,More O'Ferrall, Rory A.
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p. 19718 - 19728
(2012/01/31)
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- Synthesis, electrochemical and optical properties of stable yellow fluorescent fluoranthenes
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Figure presented A novel series of thermally stable yellow light emitting fluoranthenes with an amine donor and a nitrile acceptor was prepared from a ketene-S,S-acetal under mild conditions without using an organometal catalyst. The organic light emitting device of yellow fluoranthene 10b exhibited substantially low turn-on voltage (2.6 V) and maximum brightness of 470 Cd/m2 with luminance efficiency of 2.0 Cd/A without using any dopant.
- Goel, Atul,Kumar, Vijay,Chaurasia, Sumit,Rawat, Madhu,Prasad, Ramesh,Anand
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supporting information; experimental part
p. 3656 - 3662
(2010/07/07)
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- Novel polyaniline supported cobalt catalyzed aerobic oxidation of unsaturated organic compounds
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The oxidation of organic compounds with carbon-carbon double bond with molecular oxygen under atmospheric pressure in the presence of new polyaniline supported catalyst 1 has been studied. This catalyst turned out to be efficient and selective for oxidation of some unsaturated organic compounds. Oxidation of alkenes, cycloalkenes and terpenes give corresponding epoxy derivatives, whereas organic compounds with carbon carbon double bond in benzylic position give ketones as a main product. Taylor & Francis Group, LLC.
- Pielichowski, Jan,Kowalski, Grzegorz
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experimental part
p. 105 - 111
(2011/08/03)
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- New cyclopentane derivatives as inhibitors of steroid metabolizing enzymes AKR1C1 and AKR1C3
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A series of cyclopentane derivatives was synthesized and evaluated for inhibition of the steroid metabolizing enzymes AKR1C1 and AKR1C3. Selective inhibitors that are active in the low micromolar range were identified. These compounds represent promising starting points in the development of new anticancer agents for the treatment of hormone-dependent forms of cancer and other diseases where AKR1C1 and AKR1C3 are involved.
- Stefane, Bogdan,Brozic, Petra,Vehovc, Matej,Rizner, Tea Lanisnik,Gobec, Stanislav
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experimental part
p. 2563 - 2571
(2009/10/17)
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- New recoverable organoselenium catalyst for hydroperoxide oxidation of organic substrates
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New benzisoselenazol-3(2H)-one covalently bounded to a silica support was synthesized and characterized. It was used as an effective, selective, and easy-to-regenerate catalyst for t-BuOOH and H2O2 oxidation of alkyl arenes to alkyl aryl ketones, aromatic aldehydes to arene carboxylic acids, and sulfoxides and/or sulfones. Copyright Taylor & Francis Group, LLC.
- Wojtowicz, Halina,Soroko, Grazyna,Mlochowski, Jacek
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p. 2000 - 2010
(2008/09/21)
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- Anthrone-derived NHPI analogues as catalysts in reactions using oxygen as an oxidant
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An enantioselective synthesis of anthrone-derived NHPI analogues has been developed. One of these analogues, in combination with Co salts, was employed to catalyse the aerobic oxidation of benzylic compounds and diols. Exploratory studies using a racemic version of the catalyst were also conducted. Radical addition of dioxolanes or alcohols to activated alkenes with molecular oxygen as the terminal oxidant was also shown to be catalysed with NHPI analogues.
- Shen, Juan,Tan, Choon-Hong
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supporting information; experimental part
p. 4096 - 4098
(2009/02/07)
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- New efficient organocatalytic oxidation of benzylic compounds by molecular oxygen under mild conditions
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Efficient aerobic oxidation of benzylic compounds has been achieved under no irradiation using a new organocatalytic system in the presence of acridine yellow and N-hydroxyphthalimide with assistance of a catalytic amount of molecular bromine. Various substrates, especially alkylaromatics, were effectively oxygenated to the corresponding carbonyl compounds with molecular oxygen as oxidant under mild conditions. For instance, indan was oxidized with 92% conversion and 79% selectivity for 1-indanone under 0.3 MPa of O2 at 75°C.
- Tong, Xinli,Xu, Jie,Miao, Hong,Gao, Jin
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p. 1763 - 1766
(2007/10/03)
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- Selective organocatalytic oxygenation of hydrocarbons by dioxygen using anthraquinones and N-hydroxyphthalimide
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(Chemical Equation Presented) Purely organic and catalytic systems of anthraquinones and N-hydroxyphthalimide efficiently promote oxygenation of hydrocarbons with dioxygen under mild conditions, e.g., fluorene can be converted completely to fluorenone with 85% yield at 80°C.
- Yang, Guanyu,Zhang, Qiaohong,Miao, Hong,Tong, Xinli,Xu, Jie
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p. 263 - 266
(2007/10/03)
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- REMEDY FOR SLEEP DISTURBANCE
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The present invention has been made based on the finding that a compound acting on the ORL-1 receptor as an agonist acts as a non-photic entrainment factor, and advances the circadian rhythm phase, and provides a novel therapeutic agent for a sleep disorder such as circadian rhythm sleep disorder, more particularly, an agent for the prophylaxis and/or treatment of a sleep disorder, which contains an ORL-1 receptor agonist, and a novel compound useful as such agent for the prophylaxis and/or treatment.
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- Nitrous oxide oxidation catalyzed by ruthenium porphyrin complex
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Dinitrogen oxide was employed as a clean oxidant for various oxidations in the presence of a catalytic amount of dioxoruthenium tetramesitylporphyrin complex (Ru(tmp)(O)2). A variety of olefins, secondary alcohols, and benzyl alcohols were smoothly oxidized to the corresponding epoxides, ketones, and aldehydes in high yields. In the oxidation of 9,10-dihydroanthracene derivatives, the competitive reactions affording anthraquinones and anthracenes could be regulated by the reaction conditions. At a high temperature (200°C), anthraquinones were selectively produced, while the anthracenes were selectively produced by the addition of sulfuric acid.
- Tanaka, Hirotaka,Hashimoto, Kentaro,Suzuki, Kyosuke,Kitaichi, Yasunori,Sato, Mitsuo,Ikeno, Taketo,Yamada, Tohru
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p. 1905 - 1914
(2007/10/03)
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- A p-benzyne to m-benzyne conversion through a 1,2-shift of a phenyl group. Completion of the benzyne cascade
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Pyrolysis of 1,6-diphenylhexa-1,5-diyne-cis-3-ene at 800-1000 °C leads to a mixture of 1- and 2-phenylbiphenylene, along with triphenylene. Formation of the two biphenylenes is taken as strong evidence of the rearrangement of a p-benzyne into a m-benzyne through a shift of one of the phenyl groups. Copyright
- Polishchuk, Alexei L.,Bartlett, Kevin L.,Friedman, Lee A.,Jones Jr., Maitland
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p. 798 - 806
(2007/10/03)
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- Aryl substituted 1,4-diazepanes and method of use thereof
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Aryl substituted 1,4-diazepanes are provided such as derivatives of 6-(1,4-diazepan-1-yl)benzo[cd]indol-2(1H)-one, 6-(1,4-diazepan-1-yl)acenaphthylen-1(2H)-one and 5-(1,4-diazepan-1-yl)-2H-naphtho[1,8-cd]isothiazole-1,1-dioxide. Also provided are pharmaceutical compositions containing one or more of the aryl substituted 1,4-diazepanes. The aryl substituted 1,4-diazepanes are useful for treating disorders or deficiencies associated with the 5-HT2C receptor.
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Page column 43
(2008/06/13)
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- Scope of enantioselective Palladium(II)-catalyzed aerobic alcohol oxidations with (-)-sparteine
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Evaluation of the substrate scope for Pd(II)/ (-)-sparteine catalyzed aerobic oxidative kinetic resolution of secondary alcohols is disclosed. An improved system is found with use of tert-butyl alcohol solvent in which benzylic and aliphatic alcohols as well as alcohols containing olefins are effectively oxidatively resolved. For substrates that successfully undergo oxidative kinetic resolution, krel values are generally between 10 and 20. Successful scale-up of various substrates to 10-mmol scale is described. Extension to oxidative desymmetrization of 1,3-meso-diols is successful with enantiomeric excesses ranging from 78 to 85%.
- Mandal, Sunil K.,Jensen, David R.,Pugsley, Jacob S.,Sigman, Matthew S.
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p. 4600 - 4603
(2007/10/03)
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- Palladium-catalyzed aerobic oxidative kinetic resolution of alcohols with an achiral exogenous base
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Substitution of exogenous (-)-sparteine for a more practical achiral base in the aerobic oxidative kinetic resolution of secondary alcohols is described. Carbonate bases are the most effective of those screened and allow for effective kinetic resolution of benzylic, allylic, and aliphatic substrates. The procedure was also successfully extended to the oxidative desymmetrization of meso diols.
- Mandal, Sunil K.,Sigman, Matthew S.
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p. 7535 - 7537
(2007/10/03)
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- Catalytic oxidation of acenaphthene and its derivatives in acetic acid
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The chemistry of formation of products of acenaphthene oxidation in the presence of the catalyst containing both manganese and cobalt bromides under batch conditions is discussed. The main reaction products are acenaphthene quinone, acenaphthenol-9, trans-acenaphthylene glycol, naphthalide, and naphthalic anhydride. The sequence of reactions leading to the final products is established. It is shown that the main oxidation product in the presence of the manganese-based catalyst is naphthalic anhydride, and the main product in the presence of the cobalt-based catalyst is acenaphthene quinone. The process and engineering techniques providing for the high overall and fractional yields of the desired products are discussed.
- Bukharkina, Tatiana V.,Grechishkina, Olga S.,Digurov, Nikolai G.,Kon'kov, Ivan I.
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p. 394 - 400
(2013/09/06)
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- Tricyclic compounds, preparation method and pharmaceutical compositions containing same
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The invention concerns compounds of formula (I) in which: A forms a tricyclic system of formula A1, A2, A3or A4; R1represents a hydrogen atom, an alkyl, hydroxy, alkoxy or oxo group; (R2)mand (R3)m′are such as defined in the description; n represents an integer such that 0≦n≦3; p represents an integer such as defined in the description; B represents a group (a) or (b). The invention is useful for preparing medicines.
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- Nitrous oxide oxidation of secondary and benzylic alcohols using ruthenium complex catalyst
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Catalytic N2O oxidation of various secondary and benzylic alcohols using a ruthenium porphyrin complex is presented. Both secondary and benzylic alcohols were smoothly consumed to give the corresponding ketones and aldehydes in high yields. Nitrous oxide (N2O) is expected to be a new terminal oxidant producing only dinitrogen gas as the only by-product to provide a less wasteful process.
- Hashimoto, Kentaro,Kitaichi, Yasunori,Tanaka, Hirotaka,Ikeno, Taketo,Yamada, Tohru
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p. 922 - 923
(2007/10/03)
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- Importance of peri-interactions on the stereospecificity of rat hydroxysteroid sulfotransferase STa with 1-arylethanols
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Hydroxysteroid (alcohol) sulfotransferases catalyze the sulfation of polycyclic aromatic hydrocarbons (PAHs) that contain benzylic hydroxyl functional groups. This metabolic reaction is often a critical step in the activation of a hydroxyalkyl-substituted PAH to form an electrophilic metabolite that is capable of forming covalent bonds at nucleophilic sites on DNA, RNA, and proteins. Since hydroxyalkyl-substituted PAHs are often metabolically formed by the stereoselective enzymatic hydroxylation of a benzylic position on an alkyl-substituted PAH, we have investigated the possibility that the sulfation of hydroxyalkyl aromatic hydrocarbons is also stereoselective. Homogeneous preparations of rat hepatic hydroxysteroid (alcohol) sulfotransferase STa were utilized to investigate the stereoselectivity of its catalytic function with the enantiomers of model 1- arylethanols. While only minimal stereoselectivity was observed for the catalytic efficiency of STa with the enantiomers of 1-(2-naphthyl)ethanol and 1-acenaphthenol, the enzyme was stereospecific for (R)-(+)-1-(1- naphthyl)ethanol, (R)-(+)-1-(1-pyrenyl)ethanol, and (R)-(+)-1-(9- phenanthryl)ethanol as substrates. Moreover, (S)-(-)-1-(1-naphthyl)ethanol, (S)-(-)-1-(1-pyrenyl)ethanol, and (S)-(-)-1-(9-phenanthryl)ethanol were competitive inhibitors of STa. Structural and conformational analyses of these 1-arylethanols indicated that steric interactions between the substituents on the benzylic carbon and the hydrogen in the peri-position on the aromatic ring system were important determinants of the stereospecificity of the enzyme with these molecules. The findings presented here have implications for the more accurate prediction of the ability of hydroxyalkyl- substituted PAHs to be activated via metabolic formation of electrophilic sulfuric acid esters.
- Banoglu, Erden,Duffel, Michael W.
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p. 278 - 285
(2007/10/03)
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- Acenaphthene Oxidation in the Presence of Tetraethylammonium and Tetrabutylammonium Perchlorates
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Liquid-phase oxidation of acenaphthene in the presence of tetraethylammonium and tetrabutylammonium perchlorates proceeds with chain initiation by degenerate branching through 9-acenaphthyl hydroperoxide the secondary hydroxide that is the main reaction product. In addition, 9-acenaphthenone, 9-acenaphthenol, and acenaphthenequinone are formed as the main reaction products. A simulation of this process showed that the perchlorate catalysis was weakened in the course of oxidation because of deactivation of the perchlorates. The rate of molecular decomposition of the hydroperoxide is higher than that of radical decomposition by a factor of 2 to 3. The initiation rate constant in the catalysis with tetrabutylammonium perchlorate is six times as high as that with tetraethylammonium perchlorate.
- Opeida,Zalevskaya,Vasil'ev
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p. 328 - 335
(2007/10/03)
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- Novel Syntheses of Decacyclene by Deoxygenating Cyclotrimerisation of Acenaphthenequinone with Zero-valent Titanium or Phosphorus Pentasulfide
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Decacyclene (2) was obtained in 15-21% yield by reaction of acenaphthenequinone (6) with bis(η6-biphenyl)titanium(0) (9) in toluene or diglyme at 110°C and in 18% yield by reaction of 6 with phosphorus pentasulfide in boiling toluene. The new reactions are used to attempt the conversion of 3,8-dibromoacenaphthenequinone (7) to 3,4,9,10,15,16-hexabromodecacyclene (3) which is considered to serve as a suitable precursor for the bowl-shaped polycyclic aromatic hydrocarbon C 36H12 (1).
- Zimmermann, Klaus,Haenel, Matthias W.
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p. 609 - 611
(2007/10/03)
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- Synthetic approaches to the hypothetical lactone intermediate in the pyrolytic conversion of 8-methylcyclobuta[a]naphthalene-1,2-dione into acenaphthylene
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Synthetic approaches to the hypothetical lactone intermediate 8,8a-dihydro-2H-acenaphtho[1,8-bc]furan-2-one (2) based on intramolcular Diels-Alder reaction, and on intramolecular alkylation by diazoacetate groups, were not useful. Generation and pyrolysis of the 9-diazomethylnaphtho[1,2-c]furan-3(1H)-one (19) derived from the corresponding 9-formyl compound (15) gave products including acenaphthylene, consistent with the intermediacy of the lactone (2).
- Brown, Roger F.C.,Eastwood, Frank W.,Wong, Neil R.
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p. 793 - 800
(2007/10/03)
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- Oxidation of cumene and acenaphthene by oxygen in the presence of tetraalkylammonium perchlorates
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Tetraalkylammonium perchlorates catalyze oxidation of cumene and acenaphthene by oxygen. The perchlorates are more stable in these reactions than halides with the same cations. The perchlorate-initiated decomposition of hydroperoxides depends on the structure of the latter: secondary acenaphthyl hydroperoxide reacts with perchlorates more readily than does tertiary cumyl hydroperoxide. 1996 MAEe Cyrillic signΚ Hayκa/Interperiodica Publishing.
- Opeida,Zalevskaya
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p. 524 - 529
(2007/10/03)
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- New π-electron donor systems based on acenaphtho[1,2-b][1,4]-dithiine
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Syntheses of the acenaphtho[1,2-b][1,4]dithune derivatives 12, 25 and 29 are reported. Cyclic voltammetric studies reveal that these compounds undergo reversible single-electron oxidations at 2TCNQ (1:1 stoichiometry) and compound 33 are reported. In the structure of 25:Br2TCNQ, molecules of 25 and Br2TCNQ form mixed stacks. The folding of the donor along the S ... S vector in the complex is 17° (cf. 48° in pure 25) and the conformation of 25 is discussed in the light of previous studies on 1,4-dithiine derivatives. An interesting feature of the crystal structure of 33 is the formation of pseudo-dimers with two short intermolecular Se ... Se contacts.
- Bryce, Martin R.,Chesney, Antony,Lay, Alexander K.,Batsanov, Andrei S.,Howard, Judith A. K.
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p. 2451 - 2459
(2007/10/03)
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- CATALYSIS OF THE OXIDATION OF ACENAPHTHENE BY TETRAETHYL AND TETRABUTYL AMMONIUM HALIDES
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A liquiud-phase oxidation of acenaphthene in the presence of tetraethyl and tetrabutyl ammonium halides proceeds with chain initiation via degenerate branching on a secondary hydroperoxide-acenaphthyl-9-hydroperoxide (AHP-9).In the series of salts investigated, change in the cation had virtually no effect on the activity of the salt, while variation in the anion indicates that, under identical oxidation conditions (a constant concentration of the catalyst and acenaphthene and a constant reaction time), the degree of conversion of the hydrocarbon increases in the order iodidebromidechloride with an almost identical selectivity of the reaction with respect to the hydroperoxide formed.When halides of quaternary ammonium salts are used, oxidation begins to develop actively from almost the first minutes, and in most cases the maximum rate of the reaction is rapidly attained.The selectivity of the process with respect to the hydroperoxide depends on the conditions and varies in a wide range (from 5 to 70percent).
- Opeida, I. A.,Zalevskaya, N. M.,Vasil'yev, A. Yu.
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p. 535 - 543
(2007/10/03)
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- Efficient Oxidation of organic Compounds with Sodium and Silver Bromates NaBrO3, AgBrO3, in Non-Aqueous Solvents in the Presence of Lewis Acids
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The syntehtic utility of sodium and silver bromates in the presence of Lewis acids as catalysts in organic solvents is described.They are efficient for the oxidation of alcohols, acyloins, and hydroquinones to their corresponding carbonyl compounds.The oxidation coupling of thiols performs well in the absence of the catalysts.Silver bromate is able to transform primary benzylic and saturated alcohols, aldehydes, and primary benzylic carbon-hydrogen bonds to their carboxylic acids efficiently.Secondary benzylic carbon-hydrogen bonds are oxidized to their carbonyl compounds with sodium and silver bromates.
- Firouzabadi, Habib,Mohammadpoor-Baltork, Iraj
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p. 2319 - 2326
(2007/10/03)
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- Synthesis of 1-Arylacenaphthopyrazoles and 5,7-Dehydro-5H,7H-benzoacenaphtho-1,3a,6a-triazapentalenes
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2-Benzoyl- 5 and 2-acetylacenaphthenone 6, prepared from the corresponding 1-acyl-2-(1-pyrrolidinyl)-acenaphthylenes 2 and 3, reacted with arylhydrazines 8 under acidic conditions to give the corresponding 1-arylacenaphthopyrazoles 9 and 10.Novel heteropentalene mesomeric betaines, 5,7-dehydro-5H,7H-benzoacenaphtho-1,3a,6a-triazapentalenes 13 and 14 were prepared by reductive cyclization of 1-(o-nitrophenyl)acenaphthopyrazoles 9d and 10d, respectively.
- Tsuge, Otohiko,Hatta, Taizo,Kojima, Hisashi,Miyahara, Nobutaka,Sugaya, Masafumi
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p. 1283 - 1288
(2007/10/02)
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