- 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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- Silylative Kinetic Resolution of Racemic 1-Indanol Derivatives Catalyzed by Chiral Guanidine
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Efficient kinetic resolution of racemic 1-indanol derivatives was achieved using triphenylchlorosilane by asymmetric silylation in the presence of chiral guanidine catalysts. The chiral guanidine catalyst (R,R)-N-(1-(β-naphthyl)ethyl)benzoguanidine was found to be highly efficient as only 0.5 mol % catalyst loading was sufficient to catalyze the reaction of various substrates with appropriate conversion and high s-values (up to 89). This catalyst system was successfully applied to the gram-scale silylative kinetic resolution of racemic 1-indanol with high selectivity.
- Yoshimatsu, Shuhei,Yamada, Akira,Nakata, Kenya
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p. 452 - 458
(2018/02/19)
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- 1-acenaphthenol synthesis and enantiomer separation method
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The invention discloses a 1-acenaphthenol synthesis and enantiomer separation method. The method particularly comprises the following steps that 1-acenaphthenone serves as a raw material, catalytic reduction hydrogenation can be conducted through a catalyst to obtain racemic 1-acenaphthenol, the racemic 1-acenaphthenol is subjected to dynamic kinetic splitting and then separated to obtain an R-1-acenaphthenol acyl compound and S-1-acenaphthenol, the 1-acenaphthenol is subjected to dynamic kinetic splitting, only an R-1-acenaphthenol acyl compound is obtained, the R-1-acenaphthenol acyl compound obtained through kinetic splitting or dynamic kinetic splitting is hydrolyzed, and then R-1-acenaphthenol can be obtained. The method has the advantages of being easy to implement, high in product yield, good in optical purity and the like, and great guidance and application value is achieved in 1-acenaphthenol synthesis and splitting research.
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Paragraph 0012
(2017/08/27)
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- The Oxidation of Hydrophobic Aromatic Substrates by Using a Variant of the P450 Monooxygenase CYP101B1
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The cytochrome P450 monooxygenase CYP101B1, from a Novosphingobium bacterium is able to bind and oxidise aromatic substrates but at a lower activity and efficiency than norisoprenoids and monoterpenoid esters. Histidine 85 of CYP101B1 aligns with tyrosine 96 of CYP101A1, which, in the latter enzyme forms the only hydrophilic interaction with its substrate, camphor. The histidine residue of CYP101B1 was mutated to phenylalanine with the aim of improving the activity of the enzyme for hydrophobic substrates. The H85F mutant lowered the binding affinity and activity of the enzyme for β-ionone and altered the oxidation selectivity. This variant also showed enhanced affinity and activity towards alkylbenzenes, styrenes and methylnaphthalenes. For example the rate of product formation for acenaphthene oxidation was improved sixfold to 245 nmol per nmol CYP per min. Certain disubstituted naphthalenes and substrates, such as phenylcyclohexane and biphenyls, were oxidised with lower activity by the H85F variant. Variants at H85 (A and G) designed to introduce additional space into the active site so as to accommodate these larger substrates did not improve the oxidation activity. As the H85F mutant of CYP101B1 improved the oxidation of hydrophobic substrates, this residue is likely to be in the substrate binding pocket or the access channel of the enzyme. The side chain of the histidine might interact with the carbonyl groups of the favoured norisoprenoid substrates of CYP101B1.
- Sarkar, Md. Raihan,Lee, Joel H. Z.,Bell, Stephen G.
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p. 2119 - 2128
(2017/10/12)
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- Asymmetric Transfer Hydrogenation of (Hetero)arylketones with Tethered Rh(III)-N-(p-Tolylsulfonyl)-1,2-diphenylethylene-1,2-diamine Complexes: Scope and Limitations
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A series of new tethered Rh(III)/Cp? complexes containing the N-(p-tolylsulfonyl)-1,2-diphenylethylene-1,2-diamine ligand have been prepared, characterized, and evaluated in the asymmetric transfer hydrogenation (ATH) of a wide range of (hetero)aryl ketones. The reaction was performed under mild conditions with the formic acid/triethylamine (5:2) system as the hydrogen source and provided enantiomerically enriched alcohols with good yields and high to excellent enantioselectivities. Although the nature of the substituents on the phenyl tethering ring did not alter the stereochemical outcome of the reaction, complexes bearing electron-donating groups exhibited a higher catalytic activity than those having electron-withdrawing groups. A scale-up of the ATH of 4-chromanone to the gram scale quantitatively delivered the reduced product with excellent enantioselectivity, demonstrating the potential usefulness of these new complexes.
- Zheng, Long-Sheng,Llopis, Quentin,Echeverria, Pierre-Georges,Férard, Charlène,Guillamot, Gérard,Phansavath, Phannarath,Ratovelomanana-Vidal, Virginie
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p. 5607 - 5615
(2017/06/07)
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- Selective acetylation of primary alcohols by ethyl acetate
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A KOtBu and ethyl acetate mediated efficient methodology has been developed for the acetylation of primary and secondary alcohols where ethyl acetate is the source of acetyl group. The reaction is fast, mild, efficient, and highly selective towards the primary alcohols.
- Singha, Raju,Ray, Jayanta K.
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supporting information
p. 5395 - 5398
(2016/11/11)
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- Fabrication of CuCr2O4 spinel nanoparticles: A potential catalyst for the selective oxidation of cycloalkanes via activation of Csp3-H bond
-
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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- Ansa-Ruthenium(II) Complexes of R2NSO2DPEN-(CH2)n(η6-Aryl) Conjugate Ligands for Asymmetric Transfer Hydrogenation of Aryl Ketones
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New 3rd generation designer ansa-ruthenium(II) complexes featuring N,C-alkylene-tethered N,N-dialkylsulfamoyl-DPEN/η6-arene ligands, exhibited good catalytic performance in the asymmetric transfer hydrogenation (ATH) of various classes of (het)aryl ketones in formic acid/triethylamine mixture. In particular, benzo-fused cyclic ketones furnished 98 to >99.9% ee using a low catalyst loading.
- Ki?ic, Andrea,Stephan, Michel,Mohar, Barbara
-
supporting information
p. 2540 - 2546
(2015/08/18)
-
- 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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- Conventional chiralpak ID vs. capillary chiralpak ID-3 amylose tris-(3-chlorophenylcarbamate)-based chiral stationary phase columns for the enantioselective HPLC separation of pharmaceutical racemates
-
A comparative enantioselective analysis using immobilized amylose tris-(3-chlorophenylcarbamate) as chiral stationary phase in conventional high-performance liquid chromatography (HPLC) with Chiralpak ID (4.6mm ID×250mm, 5μm silica gel) and micro-HPLC with Chiralpak ID-3 (0.30mm ID×150mm, 3μm silica gel) was conducted. Pharmaceutical racemates of 12 pharmacological classes, namely, α- and β-blockers, anti-inflammatory drugs, antifungal drugs, dopamine antagonists, norepinephrine-dopamine reuptake inhibitors, catecholamines, sedative hypnotics, diuretics, antihistaminics, anticancer drugs, and antiarrhythmic drugs were screened under normal phase conditions. The effect of an organic modifier on the analyte retentions and enantiomer recognition was investigated. Baseline separation was achieved for 1-acenaphthenol, carprofen, celiprolol, cizolirtine carbinol, miconazole, tebuconazole, 4-hydroxy-3-methoxymandelic acid, 1-indanol, 1-(2-chlorophenyl)ethanol, 1-phenyl-2-propanol, flavanone, 6-hydroxyflavanone, 4-bromogluthethimide, and pentobarbital on the 4.6mm ID packed with a 5μm silica column using conventional HPLC. Nonetheless, baseline separation was achieved for aminoglutethimide, naftopidil, and thalidomide on the 0.3mm ID packed with a 3μm silica capillary column. Chirality 26:677-682, 2014.
- Ahmed, Marwa,Gwairgi, Marina,Ghanem, Ashraf
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p. 677 - 682
(2015/03/31)
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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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- A green route to enantioenriched (S)-arylalkyl carbinols by deracemization via combined lipase alkaline-hydrolysis/Mitsunobu esterification
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Herein we report results of the chemoenzymatic deracemization of a range of secondary benzylic acetates 1a-9a via a sequence of hydrolysis with CAL-B lipase in non-conventional media, combined with esterification of the recovered alcohol according to the Mitsunobu protocol following an enzymatic kinetic resolution (KR). The KR of racemic acetates 1a-9a via an enzymatic hydrolysis, with CAL-B lipase and Na2CO3, in non-aqueous media was optimized and gave high selectivities (E ? 200) at good conversions (C >49%) for all of the substrates studied. This method competes well with the traditional one performed in a phosphate buffer solution. The deracemization using Mitsunobu inversion gave the (S)-acetates in moderate to excellent enantiomeric excess 75% ee 99%, in acceptable isolated yields 70% yield 89%, and with some variations according to the acetate structure.
- Houiene, Zahia,Merabet-Khelassi, Mounia,Bouzemi, Nassima,Riant, Olivier,Aribi-Zouioueche, Louisa
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p. 290 - 296
(2013/04/23)
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- Enantioselective hydrosilylation of aromatic alkenes catalyzed by chiral bis(oxazolinyl)phenyl-rhodium acetate complexes
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Highly efficient and enantioselective hydrosilylation of aromatic alkenes catalyzed by the chiral rhodium acetate complexes with the bis(oxazolinyl)phenyl ligands has been reported that afforded chiral silane derivatives with up to 99% ee. Georg Thieme Ve
- Naito, Tatsuo,Yoneda, Takuma,Ito, Jun-Ichi,Nishiyama, Hisao
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p. 2957 - 2960
(2013/02/22)
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- Green methodology for enzymatic hydrolysis of acetates in non-aqueous media via carbonate salts
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Herein we report a new approach to enantiomerically enriched acetates using a lipase-catalyzed hydrolysis in non-aqueous media by alkaline carbonate salts. The use of sodium carbonate in the enzymatic hydrolysis with Candida antarctica lipase B (CAL-B) of racemic acetates shows a large enhancement of the reactivity and selectivity of this lipase. The role of the carbonate salts, the amount and the nature of the alkaline earth metal on the efficiency of this new pathway are investigated. The enzymatic kinetic resolution of acetates 1a-9a, by enzymatic-carbonate hydrolysis under mild conditions is described. In all cases, the resulting alcohols and remaining acetates were obtained in high ee values (up to >99%) while the selectivities reached E >500.
- Merabet-Khelassi, Mounia,Houiene, Zahia,Aribi-Zouioueche, Louisa,Riant, Olivier
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p. 828 - 833
(2012/09/25)
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- Solution-phase synthesis and evaluation of tetraproline chiral stationary phases
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A protocol was developed for the solution-phase synthesis of multigram amounts of two 9-fluorenylmethoxycarbonyl (Fmoc)-protected tetraproline peptides. These tetraproline peptides were then attached to amino derivatized silica gel. The replacement of the Fmoc group with the trimethylacetyl group lead to two tetraproline chiral stationary phases (CSPs). A comparison of the chromatographic behavior of these two solution-phase-synthesized tetraproline CSPs with that prepared by stepwise solid-phase synthesis revealed that all three had similar chromatographic performance for resolving 53 model analytes. This suggests that the solution-phase synthesis of oligoprolines, which allows for the specific benefits of good batch reproducibility, selector homogeneity, and possibly low cost, is a feasible alternative to the solid-phase synthesis of oligoproline CSPs. Copyright
- Dai, Zhi,Ye, Guozhong,Pittman Jr., Charles U.,Li, Tingyu
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experimental part
p. 329 - 338
(2012/05/20)
-
- Silylation-based kinetic resolution of monofunctional secondary alcohols
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The nucleophilic small molecule catalyst (-)-tetramisole was found to catalyze the kinetic resolution of monofunctional secondary alcohols via enantioselective silylation. Optimization of this new methodology allows for selectivity factors up to 25 utilizing commercially available reagents and mild reaction conditions.
- Sheppard, Cody I.,Taylor, Jessica L.,Wiskur, Sheryl L.
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supporting information; experimental part
p. 3794 - 3797
(2011/10/02)
-
- Photocatalytic degradation of polycyclic aromatic hydrocarbons in GaN:ZnO solid solution-assisted process: Direct hole oxidation mechanism
-
GaN:ZnO exhibits excellent activity for the photodegradation of PAHs, and the activity can be obviously improved by loading Pt. The degradation of PAHs in the system of GaN:ZnO is induced by the formation of holes. The holes generated then interact with PAHs to produce PAHs+, which is active enough to react with O2.
- Kou, Jiahui,Li, Zhaosheng,Guo, Yong,Gao, Jun,Yang, Ming,Zou, Zhigang
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experimental part
p. 48 - 54
(2010/10/01)
-
- 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)
-
- 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)
-
- Facile deoxygenation of dicarbonyl compounds using a samarium diiodide-additive system
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The reduction of α- and β-dicarbonyl compounds was investigated with samarium diiodide in the presence of additive. Diketones and ketocarboxylic acids were easily reduced at room temperature to give the mono-alcohols in good to excellent yield, and ketoester afforded the saturated ester as the major product in moderate yield. These reductions containing the reductive deoxygenation can be rapidly performed under the facile and mild conditions by this method.
- Kamochi, Yasuko,Kudo, Tadahiro,Masuda, Toshinobu,Takadate, Akira
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p. 1017 - 1020
(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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- On the use of succinic anhydride as acylating agent for practical resolution of aryl-alkyl alcohols through lipase-catalyzed acylation
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A comparison is carried out of the E-values recorded in the lipase-catalyzed resolution of a series of secondary aryl-alkyl alcohols with enol esters versus succinic anhydride. Whereas all the substrates could be resolved by a proper choice of the lipase/enol ester couple with moderate (E=50) to good (E>100) enantioselectivities, only some of them showed satisfactory enantioselectivity (E>50) with the use of succinic acid as acylating agent. Notably, indanol and 1-quinolin-3-yl-ethanol were resolved in a practical way, with E>100 and E>80, respectively.
- Bouzemi, Nassima,Debbeche, Hanane,Aribi-Zouioueche, Louisa,Fiaud, Jean-Claude
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p. 627 - 630
(2007/10/03)
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- Kinetic resolution of 1-acenaphthenol and 1-acetoxynaphthene through lipase-catalyzed acylation and hydrolysis
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Acenaphthenyl acetate and acenaphthenol are resolved through Pseudomonas fluorescens lipase (PFL)-catalyzed hydrolysis and acylation, respectively. By contrast, the structurally related 1-(1-naphthyl)ethyl acetate and 1-(1- naphthyl)ethanol are inactive under the same reaction conditions. (C) 2000 Elsevier Science Ltd.
- Aribi-Zouioueche, Louisa,Fiaud, Jean-Claude
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p. 4085 - 4088
(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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- The scope of catalytic asymmetric hydroboration/oxidation with rhodium complexes of 1,1'-(2-diarylphosphino-1-naphthyl)isoquinolines
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Preformed cationic Rh complexes of the title ligands are effective for the asymmetric hydroboration/oxidation of vinylarenes at ambient temperature. These vinylarenes may carry E- or Z-β substituents but not a substituents. Enantiomer excesses of up to 97% can be obtained in the most favourable cases. The enantioselectivity is moderately sensitive to the structure of the ligand: the difurylphosphino ligand gave superior results for electron-poor styrenes and the diphenylphosphino ligand the best results for electron-rich reactants. Mechanistic aspects are discussed.
- Doucet, Henri,Fernandez, Elena,Layzell, Timothy P.,Brown, John M.
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p. 1320 - 1330
(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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- (1S, 3R, 4R)-2-azanorbornyl-3-methanol oxazaborolidines in the asymmetric reduction of ketones
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Synthesis of new rigid (1S, 3R, 4R)-2-azanorbornyl-3-methanols and its application in the asymmetric borane reduction of ketones are described. The influence of temperature, solvent and concentration on the reation outcome were also studied and enantiomeric excess up to 89% could be obtained.
- Pinho, Pedro,Guijarro, David,Andersson, Pher G.
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p. 7897 - 7906
(2007/10/03)
-
- 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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- 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
-
p. 524 - 529
(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)
-
- Preparation and absolute stereochemistry of (-)-acenaphthenol
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1-Acenaphthenol was resolved by fractional crystallization of its camphanate ester followed by hydrolysis.The absolute stereochemistry of the (+)-camphanate and (-)-alcohol, derived therefrom, was established as (R) by X-ray crystallography. Keywords: (-)-acenaphthenol, stereochemistry, synthesis, X-ray crystallography.
- Hu, Yulin,Ziffer, Herman,Silverton, J. V.
-
-
- Oxygenation of Olefins under Reductive Conditions. Cobalt-Catalyzed Selective Conversion of Aromatic Olefins to Benzylic Alcohols by Molecular Oxygen and Tetrahydroborate
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A high-yield catalytic conversion of aryl olefins 1 to benzylic alcohols 2 was developed by the use of molecular oxygen and BH4- in the presence of a catalytic amount of Co(TPP).Acid-labile alcohols were prepared in good yields.The reaction was regioselective to give benzylic alcohols exclusively and nonstereoselective.Comparison of the results of the catalytic oxygenation of styrene, the stoichiometric oxygenation of alkylcobalt complex 6, and the decomposition of 1-phenylethyl hydroperoxide (7) in distribution of products and deuterium incorporation at room and low temperatures indicated the participation of 7 as the primary product, which is formed by the reaction of 6 with molecular oxygen.Co(TPP) catalyzed three elementary reactions in the overall catalytic process: formation of 7, decomposition of 7 to 2 and aryl ketone 5, and reduction of 5.
- Okamoto, Tadashi,Oka, Shinzaburo
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p. 1589 - 1594
(2007/10/02)
-
- COBALT-CATALYZED REGIOSPECIFIC CONVERSION OF ARYL-SUBSTITUTED OLEFINS INTO ALCOHOLS USING MOLECULAR OXYGEN AND TETRAHYDROBORATE. THE REACTION OF OXYGEN WITH ACTIVATED SUBSTRATES
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Aryl-substituted olefines were converted to benzyl alcohols regioselectively by the use of oxygen and tetrahydroborate in the presence of a catalytic amount of bis(dimethylglyoximato)chloro(pyridine)cobalt(III).
- Okamoto, Tadashi,Oka, Shinzaburo
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p. 2191 - 2194
(2007/10/02)
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- Formation of Alcohols from Alkenes with TiCl4-NaBH4
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The reaction of alkenes with TiCl4-NaBH4 in 1,2-dimethoxyethane afforded alcohols, the hydroxy group of which was introduced in an anti-Markovnikov direction.
- Kano, Shinzo,Tanaka, Yasuyuki,Hibino, Satoshi
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p. 414 - 415
(2007/10/02)
-