- Silicate anion-stabilized layered magnesium-aluminium hydrotalcite
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Layered magnesium-aluminum hydrotalcite (HT) were completely intercalated and stabilized with silicate anions. The silicate anion-stabilized HT retained the layered structure and possessed a high surface area of 530-540 m2 g-1 with needle-like particles 60 nm × 4 nm in dimension. The findings of FT-IR, powder XRD, TGA, DSC and 29Si MAS-NMR revealed that silicate anions were intercalated and coated on the surface of layered HTs with the formation of a solid solution of magnesium silicate and HT. The resultant silicate-anion-intercalated materials are found to be promising catalysts for the synthesis of 1-phenoxy-2-propanol using phenol with propylene oxide. The Royal Society of Chemistry 2013.
- Baskaran, Thangaraj,Kumaravel, Raju,Christopher, Jayaraj,Sakthivel, Ayyamperumal
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- Water-resistant solid Lewis acid catalysts: Meerwein-Ponndorf-Verley and Oppenauer reactions catalyzed by tin-beta zeolite
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The catalytic activity of Sn-beta zeolite in the Meerwein-Pondorf-Verley reduction of carbonyl compounds with secondary alcohols as reductants and Oppenauer oxidation of alcohols were performed with quantitative yields to the corresponding product. The catalyst had an excellent activity and selectivity even after four catalytic recycles, and good stereoselectivities to the thermodynamic less favorable cis-alcohol isomer when alkyl-cyclohexanones were used as substrates. A prochiral ketone was reduced within an enantiomeric excess close to 50% when using a chiral alcohol as the reducing reactant. IR studies using cyclohexanone as probe molecule over beta zeolites showed that the more specific Lewis acid sites in the framework of Sn-beta were responsible for its better catalytic activity with respect to Ti- or Al-beta. The order of hydrophobicity of the samples was Ti-beta > Sn-beta > Al-beta. Ti-beta and Sn-beta retained a higher percentage of catalytic activity when water was present in the reaction media. Even with ~ 4 wt % of H2O (0.2 g) in the media, Sn-beta yielded a higher turnover number than Ti- or Al-beta when working in the absence of water.
- Corma, Avelino,Domine, Marcelo E.,Valencia, Susana
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- Resolution of 1-phenoxy-, 1-phenylmethoxy- and 1-(2-phenylethoxy)-2-propanol and their butanoates by hydrolysis with lipase B from Candida antarctica
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Resolutions of butanoic esters of 1-phenoxy-2-propanol, 1-phenylmethoxy-2-propanol and 1-(2-phenylethoxy)-2-propanol have been studied with four different lipases as catalysts. Using lipase B from Candida antarctica very high enantiomer ratios were obtained. These substrate-lipase pairs represent an excellent way of getting enantiomerically pure protected 1,2-propanediols in high chemical yield. Copyright (C) Elsevier Science Ltd.
- Hoff, Bard H.,Waagen, Viggo,Anthonsen, Thorleif
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- A SIMPLE METHOD FOR CALCULATING ENANTIOMER RATIO AND EQUILIBRIUM CONSTANTS IN BIOCATALYTIC RESOLUTIONS
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A computer programme for determination of equilibrium constant (K) and enantiomer ratio (E) in biocatalytic resolutions has been developed.The programme utilises experimental data, ees and eep measured at more than one conversion, and determines both K and E no matter whether the reaction is irreversible (K=0) or reversible (K>0).An estimation of errors in the calculations indicates that errors in E does not show a Gaussian distribution, while errors in K does.The usefulness of the programme has been tested in a lipase-catalysed transesterification of 1-phenoxy-2-propanol at various concentrations of acyl donor, with different solvents and at different water activities.
- Anthonsen, Henrik W.,Hoff, Bard Helge,Anthonsen, Thorleif
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- Inducing high activity of a thermophilic enzyme at ambient temperatures by directed evolution
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The long-standing problem of achieving high activity of a thermophilic enzyme at low temperatures and short reaction times with little tradeoff in thermostability has been solved by directed evolution, an alcohol dehydrogenase found in hot springs serving as the catalyst in enantioselective ketone reductions.
- Li, Guangyue,Maria-Solano, Miguel A.,Romero-Rivera, Adrian,Osuna, Sílvia,Reetz, Manfred T.
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- Improved Biocatalytic Activity of the Debaryomyces Species in Seawater
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Biocatalysis is an environmentally friendly strategy widely used in the chemical and pharmaceutical industries. One of its approaches consists in utilizing whole cells, which usually involves the consumption of large quantities of water. Oceans cover a large part of the Earth's surface, and constitute an important reservoir that can be used as an alternative to freshwater in chemical reactors. This work analyzed the behavior of several yeast halotolerant species belonging to genera Debaryomyces and Schwanniomyces in both freshwater and seawater. It concluded that these microorganisms were more resistant to organic solvents/compounds in the second medium. Their metabolic activity was also greater, which made the reduction reaction of several prochiral ketones more effective. Besides, yeasts cells displayed better performance in subsequent recycling steps, which could help reduce the costs of the process.
- Andreu, Cecilia,del Olmo, Marcel?lí
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Read Online
- Regiodivergent Reductive Opening of Epoxides by Catalytic Hydrogenation Promoted by a (Cyclopentadienone)iron Complex
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The reductive opening of epoxides represents an attractive method for the synthesis of alcohols, but its potential application is limited by the use of stoichiometric amounts of metal hydride reducing agents (e.g., LiAlH4). For this reason, the corresponding homogeneous catalytic version with H2 is receiving increasing attention. However, investigation of this alternative has just begun, and several issues are still present, such as the use of noble metals/expensive ligands, high catalytic loading, and poor regioselectivity. Herein, we describe the use of a cheap and easy-To-handle (cyclopentadienone)iron complex (1a), previously developed by some of us, as a precatalyst for the reductive opening of epoxides with H2. While aryl epoxides smoothly reacted to afford linear alcohols, aliphatic epoxides turned out to be particularly challenging, requiring the presence of a Lewis acid cocatalyst. Remarkably, we found that it is possible to steer the regioselectivity with a careful choice of Lewis acid. A series of deuterium labeling and computational studies were run to investigate the reaction mechanism, which seems to involve more than a single pathway.
- De Vries, Johannes G.,Gandini, Tommaso,Gennari, Cesare,Jiao, Haijun,Pignataro, Luca,Stadler, Bernhard M.,Tadiello, Laura,Tin, Sergey
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p. 235 - 246
(2022/01/03)
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- Primary Alcohols via Nickel Pentacarboxycyclopentadienyl Diamide Catalyzed Hydrosilylation of Terminal Epoxides
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The efficient and regioselective hydrosilylation of epoxides co-catalyzed by a pentacarboxycyclopentadienyl (PCCP) diamide nickel complex and Lewis acid is reported. This method allows for the reductive opening of terminal, monosubstituted epoxides to form unbranched, primary alcohols. A range of substrates including both terminal and nonterminal epoxides are shown to work, and a mechanistic rationale is provided. This work represents the first use of a PCCP derivative as a ligand for transition-metal catalysis.
- Lambert, Tristan H.,Steiniger, Keri A.
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supporting information
p. 8013 - 8017
(2021/10/25)
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- Selective Cross-Dehydrogenative C(sp3)-H Arylation with Arenes
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Selective C(sp3)-C(sp2) bond construction is of central interest in chemical synthesis. Despite the success of classic cross-coupling reactions, the cross-dehydrogenative coupling between inert C(sp3)-H and C(sp2)-H bonds represents an attractive alternative toward new C(sp3)-C(sp2) bonds. Herein, we establish a selective inter-and intramolecular C(sp3)-H arylation of alcohols with nondirected arenes that thereby provides a general pathway to access a wide range of β-arylated alcohols, including tetrahydronaphthalen-2-ols and benzopyran-3-ols, with high to excellent chemo-and regioselectivity.
- Hao, Hong-Yan,Mao, Yang-Jie,Xu, Zhen-Yuan,Lou, Shao-Jie,Xu, Dan-Qian
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supporting information
p. 2396 - 2402
(2020/03/13)
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- Preparation methods and applications of chiral spirophosphine-nitrogen-phosphine tridentate ligand and iridium catalyst thereof
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The invention relates to preparation methods and applications of a chiral spirophosphine-nitrogen-phosphine tridentate ligand SpiroPNP and an iridium catalyst Ir-SpiroPNP thereof. The chiral spirophosphine-nitrogen-phosphine tridentate ligand is a compound represented by a formula I, or a racemate or an optical isomer thereof, or a catalytically acceptable salt thereof, and is mainly structurallycharacterized by having a chiral spiro indane skeleton and a phosphine ligand with a large steric hindrance substituent. The chiral spirophosphine-nitrogen-phosphine tridentate ligand can be synthesized by taking a 7-diaryl/alkylphosphino-7'-amino-1,1'-spiro indane compound with a spiro skeleton as a chiral starting raw material. The iridium catalyst of the chiral spirophosphine-nitrogen-phosphinetridentate ligand is a compound represented by a formula II which is described in the specification, or a raceme or an optical isomer, or a catalytically acceptable salt thereof, can be used for catalyzing asymmetric catalytic hydrogenation reaction of carbonyl compounds, particularly shows high yield (greater than 99%) and enantioselectivity (as high as 99.8% ee) in asymmetric hydrogenation reaction of simple dialkyl ketone, and has practical value.
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Paragraph 0265-0272
(2020/08/18)
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- CATALYST FOR PREPARING PROPYLENE GLYCOL PHENYL ETHER AND METHOD FOR SYNTHESIZING PROPYLENE GLYCOL PHENYL ETHER
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Disclosed is a method for preparing propylene glycol phenyl ether, comprising carrying out a polymerization reaction of phenol and a propylene oxide in the presence of a quaternary phosphonium salt compound as a catalyst. Preferably, the method comprises mixing phenol and a quaternary phosphonium salt compound, and then adding propylene oxide under oxygen-free conditions, wherein the phenol is polymerized with the propylene oxide to produce the propylene glycol phenyl ether. The propylene glycol phenyl ether thus prepared has few impurities and contains no metal ions, such as potassium and sodium, and does not require subsequent operations to remove metal ions and perform rectification separation, thereby reducing the costs and allowing same to be directly applied to high-standard industrial production.
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Paragraph 0022-0049
(2020/06/08)
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- Highly Enantioselective Transfer Hydrogenation of Prochiral Ketones Using Ru(II)-Chitosan Catalyst in Aqueous Media
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Unprecedentedly high enantioselectivities are obtained in the transfer hydrogenation of prochiral ketones catalyzed by a Ru complex formed in situ with chitosan chiral ligand. This biocompatible, biodegradable chiral polymer obtained from the natural chitin afforded good, up to 86 % enantioselectivities, in the aqueous-phase transfer hydrogenation of acetophenone derivatives using HCOONa as hydrogen donor. Cyclic ketones were transformed in even higher, over 90 %, enantioselectivities, whereas further increase, up to 97 %, was obtained in the transfer hydrogenations of heterocyclic ketones. The chiral catalyst precursor prepared ex situ was examined by scanning electron microscopy, FT-mid- and -far-IR spectroscopy. The structure of the in situ formed catalyst was investigated by 1H NMR spectroscopy and using various chitosan derivatives. It was shown that a Ru pre-catalyst is formed by coordination of the biopolymer to the metal by amino groups. This precursor is transformed in water insoluble Ru-hydride complex following hydrogen donor addition. The practical value of the developed method was verified by preparing over twenty chiral alcohols in good yields and optical purities. The catalyst was applied for obtaining optically pure chiral alcohols at gram scale following a single crystallization.
- Sz?ll?si, Gy?rgy,Kolcsár, Vanessza Judit
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p. 820 - 830
(2018/12/13)
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- Revisiting Hydroxyalkylation of Phenols with Cyclic Carbonates
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Described is a tetrabutylammonium fluoride-mediated hydroxyalkylation reaction of phenols with cyclic carbonates. This operationally simple method enables the synthesis of a variety of aryl β-hydroxyethyl ethers in good to excellent yields with a very small amount of catalyst loading (0.1–1 mol%). Of particular note is the efficient conversion of aromatic diols and phloroglucinol to the corresponding bis- and tris-hydroxyethylated products. To further showcase the versatility of this protocol, guaifenesin was prepared with a single step by the condensation of guaiacol and glycerol carbonate. We also developed a flow ethoxylation process permitting the continuous synthesis of multiflorol. (Figure presented.).
- Kao, Shih-Chieh,Lin, Yi-Ching,Ryu, Ilhyong,Wu, Yen-Ku
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supporting information
p. 3639 - 3644
(2019/07/10)
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- PYRIDIN-3-YL ACETIC ACID DERIVATIVES AS INHIBITORS OF HUMAN IMMUNODEFICIENCY VIRUS REPLICATION
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Disclosed are compounds of Formula I, including pharmaceutically acceptable salts, pharmaceutical compositions comprising the compounds, methods for making the compounds and their use in inhibiting HIV integrase and treating those infected with HIV or AIDS.
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Page/Page column 166; 167
(2020/01/11)
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- PROCESS FOR MAKING FORMIC ACID UTILIZING LOWER-BOILING FORMATE ESTERS
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Disclosed is a process for recovering formic acid from a formate ester of a C3 to C4 alcohol. Disclosed is also a process for producing formic acid by carbonylating a C3 to C4 alcohol, hydrolyzing the formate ester of the alcohol, and recovering a formic acid product. The alcohol may be dried and returned to the reactor. The process enables a more energy efficient production of formic acid than the carbonylation of methanol to produce methyl formate.
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Paragraph 00177; 00178
(2019/02/15)
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- Ruthenium-Catalyzed Selective Hydrogenation of Epoxides to Secondary Alcohols
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A ruthenium(II)-catalyzed highly selective Markovnikov hydrogenation of terminal epoxides to secondary alcohols is reported. Diverse substitutions on the aryl ring of styrene oxides are tolerated. Benzylic, glycidyl, and aliphatic epoxides as well as diepoxides also underwent facile hydrogenation to provide secondary alcohols with exclusive selectivity. Metal-ligand cooperation-mediated ruthenium trans-dihydride formation and its reaction involving oxygen and the less substituted terminal carbon of the epoxide is envisaged for the origin of the observed selectivity.
- Thiyagarajan, Subramanian,Gunanathan, Chidambaram
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supporting information
p. 9774 - 9778
(2019/12/02)
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- Biocatalytic Racemization Employing TeSADH: Substrate Scope and Organic Solvent Compatibility for Dynamic Kinetic Resolution
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Racemization in combination with a kinetic resolution is the base for a dynamic kinetic resolution (DKR). Biocatalytic racemization was successfully performed for a broad scope of sec-alcohols by employing a single alcohol dehydrogenase (ADH) variant from Thermoanaerobacter pseudoethanolicus (formerly T. ethanolicus; TeSADH W110A I86A C295A). The catalyst employed as a lyophilized whole cell preparation or cell free extract, which tolerated various non-water miscible organic solvents under micro-aqueous or two-phase conditions, whereby cyclohexane and n-hexane suited best. Various concepts for combining the enzymatic racemization with an enzymatic kinetic resolution to achieve overall a bis-enzymatic DKR were evaluated. A proof of concept showed a successful DKR with racemization in aqueous phase combined with acylation in the organic phase.
- Pop?oński, Jaros?aw,Reiter, Tamara,Kroutil, Wolfgang
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p. 763 - 768
(2018/02/27)
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- Methodology Development in Directed Evolution: Exploring Options when Applying Triple-Code Saturation Mutagenesis
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Directed evolution of stereo- or regioselective enzymes as catalysts in asymmetric transformations is of particular interest in organic synthesis. Upon evolving these biocatalysts, screening is the bottleneck. To beat the numbers problem most effectively, methods and strategies for building “small but smart” mutant libraries have been developed. Herein, we compared two different strategies regarding the application of triple-code saturation mutagenesis (TCSM) at multiresidue sites of the Thermoanaerobacter brockii alcohol dehydrogenase by using distinct reduced amino-acid alphabets. By using the synthetically difficult-to-reduce prochiral ketone tetrahydrofuran-3-one as a substrate, highly R- and S-selective variants were obtained (92–99 % ee) with minimal screening. The origin of stereoselectivity was provided by molecular dynamics analyses, which is discussed in terms of the Bürgi–Dunitz trajectory.
- Qu, Ge,Lonsdale, Richard,Yao, Peiyuan,Li, Guangyue,Liu, Beibei,Reetz, Manfred T.,Sun, Zhoutong
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p. 239 - 246
(2018/02/09)
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- Iridium-catalyzed efficient reduction of ketones in water with formic acid as a hydride donor at low catalyst loading
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A highly efficient and chemoselective transfer hydrogenation of ketones in water has been successfully achieved with our newly developed catalyst. Simple ketones, as well as α- or β-functionalized ketones, are readily reduced. Formic acid is used as a traceless hydride source. At very low catalyst loading (S/C = 10:000 in most cases; S/C = 50:000 or 100:000 in some cases), the iridium catalyst is impressively efficient at reducing ketones in good to excellent yields. The TOF value can be as high as up to 26:000 mol mol-1 h-1. A variety of functional groups are well tolerated, for example, heteroaryl, aryloxy, alkyloxy, halogen, cyano, nitro, ester, especially acidic methylene, phenol and carboxylic acid groups.
- Liu, Ji-Tian,Yang, Shiyi,Tang, Weiping,Yang, Zhanhui,Xu, Jiaxi
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supporting information
p. 2118 - 2124
(2018/05/24)
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- Unveiling the Hidden Performance of Whole Cells in the Asymmetric Bioreduction of Aryl-containing Ketones in Aqueous Deep Eutectic Solvents
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In this contribution, we report the first successful baker's yeast reduction of arylpropanones using deep eutectic solvents (DESs) as biodegradable and non-hazardous co-solvents. The nature of DES [e.g. choline chloride/glycerol (2:1)] and the percentage of water in the mixture proved to be critical for both the reversal of selectivity and to achieve high enantioselectivity on going from pure water (up to 98:2 er in favour of the S-enantiomer) to DES/aqueous mixtures (up to 98:2 er in favour of the R-enantiomer). As a result, both enantiomers of valuable chiral alcohols of pharmaceutical interest were prepared from the same biocatalyst by simply switching the solvent. The possible inhibition of some (S)-oxidoreductases making part of the genome of such a wild-type whole cell biocatalyst when DESs are used as co-solvents may pave the way for an anti-Prelog reduction. The scope and limitations of this kind of biotransformations for a range of aryl-containing ketones are also discussed. (Figure presented.).
- Vitale, Paola,Abbinante, Vincenzo Mirco,Perna, Filippo Maria,Salomone, Antonio,Cardellicchio, Cosimo,Capriati, Vito
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supporting information
p. 1049 - 1057
(2017/03/31)
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- In vitro biocatalytic pathway design: Orthogonal network for the quantitative and stereospecific amination of alcohols
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The direct and efficient conversion of alcohols into amines is a pivotal transformation in chemistry. Here, we present an artificial, oxidation-reduction, biocatalytic network that employs five enzymes (alcohol dehydrogenase, NADP-oxidase, catalase, amine dehydrogenase and formate dehydrogenase) in two concurrent and orthogonal cycles. The NADP-dependent oxidative cycle converts a diverse range of aromatic and aliphatic alcohol substrates to the carbonyl compound intermediates, whereas the NAD-dependent reductive aminating cycle generates the related amine products with >99% enantiomeric excess (R) and up to >99% conversion. The elevated conversions stem from the favorable thermodynamic equilibrium (K′eq = 1.88 × 1042 and 1.48 × 1041 for the amination of primary and secondary alcohols, respectively). This biocatalytic network possesses elevated atom efficiency, since the reaction buffer (ammonium formate) is both the aminating agent and the source of reducing equivalents. Additionally, only dioxygen is needed, whereas water and carbonate are the by-products. For the oxidative step, we have employed three variants of the NADP-dependent alcohol dehydrogenase from Thermoanaerobacter ethanolicus and we have elucidated the origin of the stereoselective properties of these variants with the aid of in silico computational models.
- Knaus, Tanja,Cariati, Luca,Masman, Marcelo F,Mutti, Francesco G.
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supporting information
p. 8313 - 8325
(2017/10/19)
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- Copper-catalyzed/mediated borylation reactions of epoxides with diboron reagents: access to β-hydroxyl boronic esters
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We report the first copper-catalyzed/mediated borylative ring opening reaction of epoxides. This process represents a direct borylative C(sp3)-O bond cleavage of terminal epoxide substrates with commercially available diboron reagents. A wide range of epoxides with different functional groups are involved, and were subsequently converted to the corresponding β-hydroxyl boronic esters smoothly. Moreover, the ring opening product β-pinacol boronate alcohol provided a more beneficial approach for the formation of C-C and C-N bonds.
- Ahmed, Ebrahim-Alkhalil M. A.,Lu, Xi,Gong, Tian-Jun,Zhang, Zhen-Qi,Xiao, Bin,Fu, Yao
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supporting information
p. 909 - 912
(2017/01/17)
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- Exploring the substrate scope of mutants derived from the robust alcohol dehydrogenase TbSADH
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Directed evolution of an enzyme as catalyst for a given stereoselective transformation provides a mutant for that particular reaction, but organic chemists need catalysts that are characterized by broad substrate acceptance. In a previous study we succeeded in evolving a set of variants of the thermally robust alcohol dehydrogenase TbSADH from Thermoanaerobacter brockii as a catalysts in the (R)- and (S)-selective reduction of tetrahydrofuran-3-one, this difficult-to-reduce compound being a sterically small substrate. These mutants were now tested in the asymmetric reduction of seven structurally unrelated and sterically more demanding substrates, including acetophenone, benzyl methyl ketone, 4-phenyl-2-butanone, and 2-oxo-4-phenyl-butanoic acid ethyl ester. The variants clearly out-perform WT TbSADH, but overly bulky substituted benzophenone derivatives are not accepted by WT or mutants.
- Sun, Zhoutong,Li, Guangyue,Ilie, Adriana,Reetz, Manfred T.
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supporting information
p. 3648 - 3651
(2016/07/21)
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- First example of borirane synthesis by α-olefins reaction with BCl3·SMe2 Catalyzed with (η5-C5H5)2TiCl2
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New method was developed of the synthesis of 2-phenyl(alkyl, benzyl, phenoxy)-1-chloroboriranes via reaction of α-olefins with BCl3·SMe2 catalyzed by Cp2TiCl2. The method is based on the boracyclopropanes (boriranes) formation resulting from transmetallation of titanacyclopropanes arising from the reaction of α-olefins with Cp2TiCl2. The calculations were fulfilled of thermodynamic and activation parameters of possible reaction routes.
- Khusainova,Khafizova,Tyumkina,Dzhemilev
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p. 1517 - 1523
(2015/12/30)
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- Synthesis of supported Ru-nanoparticles for selective hydrogenation of carbonyl compounds
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Ru nanoparticles were successfully supported on molecular sieves and it was further characterized by sophisticated analytical methods such as transmission electron microscopy, energydispersive X-ray spectroscopy and nitrogen adsorption techniques. Transmission electron microscopy data confirmed, indicated the formation of metal oxide nanoparticles (4.5±2 nm) on the external surface of molecular sieves. Ru supported molecular sieves were applied as a catalyst for the hydrogenation of carbonyl compounds. Aldehydes as well as ketones were successfully hydrogenated in good yield and selectivity. Easy synthesis of air/moisture stable catalyst, hassle free reaction protocol (no requirement of aqueous work-up), 7 times catalyst recycling and additive free approach were the promising outcomes of the proposed work.
- Upadhyay, Praveenkumar,Srivastava, Vivek
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p. 528 - 533
(2015/10/05)
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- Photocatalytic hydrogenolysis of epoxides using alcohols as reducing agents on TiO2 loaded with Pt nanoparticles
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Photoexcitation (λ > 300 nm) of TiO2 loaded with Pt particles promotes selective hydrogenolysis of epoxides using alcohols as reducing agents.
- Hirakawa, Hiroaki,Shiraishi, Yasuhiro,Sakamoto, Hirokatsu,Ichikawa, Satoshi,Tanaka, Shunsuke,Hirai, Takayuki
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supporting information
p. 2294 - 2297
(2015/02/05)
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- Versatile iridicycle catalysts for highly efficient and chemoselective transfer hydrogenation of carbonyl compounds in water
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Cyclometalated iridium complexes are shown to be highly efficient and chemoselective catalysts for the transfer hydrogenation of a wide range of carbonyl groups with formic acid in water. Examples include α-substituted ketones (α-ether, α-halo, α-hydroxy, α-amino, α-nitrile or α-ester), α-keto esters, β-keto esters and α,β-unsaturated aldehydes. The reduction was carried out at substrate/catalyst ratios of up to 50000 at pH 4.5 and required no organic solvent. The protocol provides a practical, easy and efficient way for the synthesis of β-functionalised secondary alcohols, such as β-hydroxyethers, β-hydroxyamines and β-hydroxyhalo compounds, which are valuable intermediates in pharmaceutical, fine chemical, perfume and agrochemical synthesis. Water wonder: Iridicycle catalysts are versatile and allow the highly efficient and chemoselective transfer hydrogenation of a variety of carbonyl compounds, including problematic and challenging ones, with formate in neat water (see scheme).
- Talwar, Dinesh,Wu, Xiaofeng,Saidi, Ourida,Salguero, Noemí Poyatos,Xiao, Jianliang
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supporting information
p. 12835 - 12842
(2015/03/30)
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- Racemization of enantiopure secondary alcohols by Thermoanaerobacter ethanolicus secondary alcohol dehydrogenase
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Controlled racemization of enantiopure phenyl-ring-containing secondary alcohols is achieved in this study using W110A secondary alcohol dehydrogenase from Thermoanaerobacter ethanolicus (W110A TeSADH) and in the presence of the reduced and oxidized forms of its cofactor nicotinamide-adenine dinucleotide. Racemization of both enantiomers of alcohols accepted by W110A TeSADH, not only with low, but also with reasonably high, enantiomeric discrimination is achieved by this method. Furthermore, the high tolerance of TeSADH to organic solvents allows TeSADH-catalyzed racemization to be conducted in media containing up to 50% (v/v) of organic solvents.
- Musa, Musa M.,Phillips, Robert S.,Laivenieks, Maris,Vieille, Claire,Takahashi, Masateru,Hamdan, Samir M.
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p. 2911 - 2915
(2013/05/08)
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- An efficient catalyst for ring opening of epoxides with phenol and thiophenol under solvent-free conditions
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An efficient and rapid procedure for ring opening reaction of various epoxides with phenol and thiophenol derivatives was developed. The procedure can be obtained at room temperature under solvent-free condition in presence of (C4H12N2)2[BiCl6] Cl·H2O (1 mol %). This catalyst can be reused several times without significant loss of activity.
- Lu, Hong-Fei,Zhou, Jun-Tao,Cheng, He-Long,Sun, Lei-Lei,Yang, Fei-Fei,Wu, Run-Ze,Gao, Yu-Hua,Luo, Zhi-Bin
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p. 11174 - 11184
(2014/01/06)
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- Straightforward heterogeneous palladium catalyzed synthesis of aryl ethers and aryl amines via a solvent free aerobic and non-aerobic dehydrogenative arylation
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Aryl ethers have been prepared from cyclohexanone derivatives and various alcohols in the presence of a catalytic amount of palladium on charcoal. The formation of an enol ether followed by an aerobic or non-aerobic dehydrogenation reaction, seem to be the key steps of this transformation. In addition, this new method was also adapted for the synthesis of arylamines.
- Sutter, Marc,Sotto, Nicolas,Raoul, Yann,Metay, Estelle,Lemaire, Marc
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supporting information
p. 347 - 352
(2013/03/28)
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- Heterogeneous palladium-catalyzed synthesis of aromatic ethers by solvent-free dehydrogenative aromatization: Mechanism, scope, and limitations under aerobic and non-aerobic conditions
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Starting from cyclohexanone derivatives and alcohols, both non-aromatic precursors, aryl ethers could be synthesized in good yields and with good selectivities in the presence of a catalytic amount of Pd/C, in one step, without added solvent, in a reaction vessel open to air. For less reactive substrates, the addition of 1-octene in a closed system under non-aerobic conditions improved the conversion. In addition, the catalyst could be recycled several times with no decrease in the yield of the aryl ether. The process was also used with tetralone derivatives and polyols. Several reactions were performed to propose a mechanism for this transformation. The formation of an enol ether followed by a dehydrogenation reaction seem to be the key steps of this reaction. Aryl ethers were prepared in good yields and with good selectivities in a solvent-free and heterogeneous catalytic dehydrogenative alkylation of cyclohexanones with various alcohols. Three different complementary routes were used, and for the first time, non-aerobic, safe conditions could be used. Moreover, the catalyst could be recycled several times with no decrease in the yield of the aryl ether. Copyright
- Sutter, Marc,Lafon, Romain,Raoul, Yann,Metay, Estelle,Lemaire, Marc
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supporting information
p. 5902 - 5916
(2013/09/23)
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- One-pot synthesis of aryloxypropanediols from glycerol: Towards valuable chemicals from renewable sources
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Glycerol offers an easy and green route for the synthesis of aryloxypropanediols of known pharmacological activity. Glycerol is selectively converted to aryloxypropanediols in a one-pot reaction, through in situ formed glycerol carbonate, under benign and solvent-free conditions. Catalyst and unreacted reagent can be recycled.
- Truscello, Ada M.,Gambarotti, Cristian,Lauria, Mirvana,Auricchio, Sergio,Leonardi, Gabriella,Shisodia, Suresh U.,Citterio, Attilio
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supporting information
p. 625 - 628
(2013/03/29)
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- Screening on the use of Kluyveromyces marxianus CBS 6556 growing cells as enantioselective biocatalysts for ketone reductions
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The versatility of Kluyveromyces marxianus CBS 6556 growing cells in the enantioselective reduction of ketone functionalities to the corresponding alcohols was exploited. In particular, methyl ketones were reduced to (S)-alcohols with ees of up to 96%. Longer chain alkyl ketones afforded, under the same experimental condition, (R)-alcohols with an ee of up to 84%. Interestingly, carbon-carbon double and the triple bonds can also be reduced in the presence of Kluyveromyces marxianus CBS 6556 yeast. A cyclic ketone, such as 2-tetralone, was also quantitatively reduced to its corresponding (S)-alcohol with ee = 76%.
- Vitale, Paola,Perna, Filippo Maria,Perrone, Maria Grazia,Scilimati, Antonio
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experimental part
p. 1985 - 1993
(2012/03/22)
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- Rhizopus arrhizus-mediated asymmetric reduction of arylalkanones: Unusual anti-Prelong products with benzyl alkyl ketones
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Rhizopus arrhizus-mediated microbial reduction of various aryl alkyl ketones afforded chiral carbinols in good yields and high enantiomeric purity. The most striking feature was the formation of the anti-Prelog (R)-alcohols with the benzyl alkyl ketones, while the other ketones ArXCOR (X = (CH 2)n, n = 0 or 2, OCH2 or SCH2 and R = Me/Et/n-Bu) furnished (S)-alcohols.
- Salvi, Neeta A.,Chattopadhyay, Subrata
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experimental part
p. 1512 - 1515
(2011/12/14)
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- Ruthenium-catalysed transfer hydrogenation reactions with dimethylamine borane
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Dimethylamine-borane adduct has been used as the hydrogen source for the reduction of carbonyl compounds, imines, oximes, nitriles, nitroarenes and alkenes using [Ru(p-cymene)Cl2]2 as the catalyst.
- Nixon, Tracy D.,Whittlesey, Michael K.,Williams, Jonathan M.J.
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supporting information; experimental part
p. 6652 - 6654
(2012/01/03)
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- An atom-economic reaction for synthesis of 1-phenoxy-2-propanol over Al2O3/MgO
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Al2O3/MgO materials with various Mg/Al molar ratios were prepared and characterized by XRD, FT-IR, SEM and BET analysis. These materials were used as catalysts for synthesis of 1-phenoxy-2-propanol (1-PhP) from phenol and propylene oxide as compared with some oxides, i.e. MgO, CaO, ZnO and Al2O3, etc. Al2O3/MgO with Al/Mg molar ratio of 1.5% exhibited outstanding catalytic performance with 98.2% conversion and 99.3% selectivity to 1-PhP at 120 °C for 5 h. This catalyst can be easily recovered and reused due to its heterogeneous catalytic nature.
- Zhang, Yongbo,Lu, Bin,Wang, Xiaoguang,Zhao, Jingxiang,Cai, Qinghai
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experimental part
p. 125 - 129
(2012/05/04)
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- Enantioselective reduction of α-substituted ketones mediated by the boronate ester TarB-NO2
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A facile and mild reduction procedure is reported for the preparation of chiral secondary alcohols prepared from α-substituted ketones using sodium borohydride and the chiral boronate ester (l)-TarB-NO2. Direct reduction of substituted ketones bearing Lewis basic heteroatoms generally provided secondary alcohols of only modest enantiomeric excess likely due to either competition between the target carbonyl and the functionalized sidechains at the Lewis acidic boron atom in TarB-NO2 or the added steric bulk of the α-sidechain. As an alternative method, these substrates were synthesized using TarB-NO2 via a two-step procedure involving the reduction of an α-halo ketone to a chiral terminal epoxide, followed by regioselective/regiospecific epoxide opening by various nucleophiles. This procedure provides access to a variety of functionalized secondary alcohols including β-hydroxy ethers, thioethers, nitriles, and amines with enantiomeric excesses of 94% and yields up to 98%.
- Eagon, Scott,Ball-Jones, Nicholas,Haddenham, Dustin,Saavedra, Jaime,Delieto, Cassandra,Buckman, Matthew,Singaram, Bakthan
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supporting information; experimental part
p. 6418 - 6421
(2010/12/30)
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- A facile enantioselective synthesis of enantiomerically pure (R)-phenoxybenzamine hydrochloride using the hydrolytic kinetic resolution method
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A practical and highly efficient enantioselective synthesis of (R)-phenoxybenzamine hydrochloride has been described for the first time using Jacobsen's hydrolytic kinetic resolution of a terminal epoxide as a key step and source of chirality.
- Nikalje, Milind D.,Sasikumar, Murugesan,Muthukrishnan, Murugan
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p. 2825 - 2829
(2011/03/23)
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- One-pot alkoxylation of phenols with urea and 1,2-glycols
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A one-pot epoxide-free alkoxylation process has been developed for phenolic compounds. The process involves heating phenols and urea in 1,2-glycols at 170-190 °C using Na2CO3/ZnO as co-catalysts under atmospheric conditions. During the course of this new alkoxylation reaction, a five-membered ring cyclic carbonate intermediate, ethylene carbonate (EC) or propylene carbonate (PPC), was produced in-transit as the key intermediate and was subsequently consumed by phenols to form alkoxylated ether alcohols as final products in excellent yields. For instance, phenol, bisphenol A (BPA), hydroquinone and resorcinol were converted into their respective mono-alkoxylated ether alcohols on each of their phenolic groups in 80-95% isolated yields. In propoxylation of phenols, this approach shows great product selectivity favoring production of high secondary alcohols over primary alcohols in isomeric ratios of nearing 95/5. Since ammonia (NH3) and carbon dioxide (CO2) evolving from the reaction can be re-combined in theory into urea for re-use, the overall net-alkoxylation by this approach can be regarded as a simple condensation reaction of phenols with 1,2-glycols giving off water as its by-product. This one-pot process is simple, safe and environmentally friendlier than the conventional alkoxylated processes based on ethylene oxide (EO) or propylene oxide (PO). Moreover, this process is particularly well-suited for making short chain-length alkoxyether alcohols of phenols.
- Lin, Hsing-Yo,Dai, Shenghong A.
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experimental part
p. 167 - 173
(2011/04/19)
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- Immobilization of β-cyclodextrin onto Dowex resin as a stationary microvessel and phase transfer catalyst
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In this study, immobilization of β-cyclodextrin onto commercial Dowex resin by covalent bond was reported. The efficiency of this biocatalyst system as a stationary microvessel and new solid-liquid phase transfer catalyst in reduction of epoxides by NaBH4 was studied.
- Kiasat, Ali Reza,Sayyahi, Soheil
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scheme or table
p. 484 - 486
(2010/12/19)
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- First use of HEH in oxazine synthesis: Hydroxy-substituted 2 H-1,4-benzoxazine derivatives
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The synthesis of 2H-1,4-benzoxazine derivatives from 1,2-epoxy-3-(2- nitroaryloxy)propanes in the presence of Hantzsch 1,4-dihydropyridine (HEH) and Pd/C as a catalyst was achieved. The nitro group was reduced before the epoxide functionality, leading to attack of the amino group on the epoxide moiety in a 6-exo-fashion. By introducing a methyl group at the 1-position, the 7-endo ring-closed product could also be formed. Georg Thieme Verlag Stuttgart - New York.
- Meng, Qing-Yuan,Liu, Qiang,Li, Jing,Xing, Rui-Guang,Shen, Xiao-Xia,Zhou, Bo
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scheme or table
p. 3283 - 3286
(2010/03/04)
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- Activity and selectivity of W110A secondary alcohol dehydrogenase from Thermoanaerobacter ethanolicus in organic solvents and ionic liquids: Mono- and biphasic media
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The asymmetric reduction of hydrophobic phenyl-ring-containing ketones and the enantiospecific kinetic resolution of the corresponding racemic alcohols catalyzed by Thermoanaerobacter ethanolicus W110A secondary alcohol dehydrogenase were performed in mono- and biphasic systems containing either organic solvents or ionic liquids. Both yield and enantioselectivity for these transformations can be controlled by changing the reaction medium. The enzyme showed high tolerance to both water-miscible and -immiscible solvents, which allows biotransformations to be conducted at high substrate concentrations. The Royal Society of Chemistry.
- Musa, Musa M.,Ziegelmann-Fjeld, Karla I.,Vieille, Claire,Phillips, Robert S.
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experimental part
p. 887 - 892
(2008/10/09)
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- SPHINGOSINE-1 -PHOSPHATE RECEPTOR AGONIST AND ANTAGONIST COMPOUNDS
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The present invention is directed to novel, potent, and selective agents, which are agonists or antagonists of the one or more of the individual receptors of the S1P receptor family. The compounds of the invention are useful as therapeutics for treating medical conditions associated with agonism or antagonism of the individual receptors of the S1P receptor family.
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Page/Page column 71
(2008/12/07)
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- METHOD FOR PRODUCING OPTICALLY ACTIVE ALCOHOL COMPOUND
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A method for producing an optically active alcohol compound comprising reacting a cyclic ether compound with a phenol compound in the presence of an asymmetric complex obtained by reacting an optically active metal complex represented by the formula (1):
- -
-
Page/Page column 11
(2008/12/04)
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- METHOD FOR PRODUCING OPTICALLY ACTIVE ALCOHOL COMPOUND
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A method for producing an optically active alcohol compound comprising reacting a cyclic ether compound with a phenol compound in the presence of an asymmetric complex obtained by reacting an optically active metal complex represented by the formula (1):
- -
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Page/Page column 11
(2008/12/04)
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- Catalytic asymmetric hydroboration of heterofunctional allylic substrates: an efficient heterogenized version
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The hydroboration of heterofunctional allylic systems with catecholborane (HBcat) using neutral and cationic rhodium complexes modified with P-P and P-N bidentate chiral ligands has been described in order to produce the secondary heteroorganoboronate ester as a major product with moderate enantioselectivity. The immobilization of cationic chiral rhodium complexes onto clays has beneficial effects on the recyclability and reuse of the catalytic system in particular for the hydroboration of allyl aryl sulfones.
- Lillo, Vanesa,Fernandez, Elena,Segarra, Anna M.
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p. 911 - 914
(2008/02/03)
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- Asymmetric reduction and oxidation of aromatic ketones and alcohols using W110A secondary alcohol dehydrogenase from Thermoanaerobacter ethanolicus
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An enantioselective asymmetric reduction of phenyl ring-containing prochiral ketones to yield the corresponding optically active secondary alcohols was achieved with W110A secondary alcohol dehydrogenase from Thermoanaerobacter ethanolicus (W110A TESADH) in Tris buffer using 2-propanol (30%), v/v) as cosolvent and cosubstrate. This concentration of 2-propanol was crucial not only to enhance the solubility of hydrophobic phenyl ring-containing substrates in the aqueous reaction medium, but also to shift the equilibrium in the reduction direction. The resulting alcohols have S-configuration, in agreement with Prelog's rule, in which the nicotinamide-adenine dinucleotide phosphate (NADPH) cofactor transfers its pro-R hydride to the re face of the ketone. A series of phenyl ring-containing ketones, such as 4-phenyl-2-butanone (1a) and 1-phenyl-1,3-butadione (2a), were reduced with good to excellent yields and high enantioselectivities. On the other hand, 1-phenyl-2-propanone (7a) was reduced with lower ee than 2-butanone derivatives. (R)-Alcohols, the anti-Prelog products, were obtained by enantiospecific oxidation of (S)-alcohols through oxidative kinetic resolution of the rac-alcohols using W110A TESADH in Tris buffer/acetone (90:10, v/v).
- Musa, Musa M.,Ziegelmann-Fjeld, Karla I.,Vieille, Claire,Zeikus, J. Gregory,Phillips, Robert S.
-
-
- Xerogel-encapsulated W110A secondary alcohol dehydrogenase from Thermoanaerobacter ethanolicus performs asymmetric reduction of hydrophobic ketones in organic solvents
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To gel well: The asymmetric reduction of hydrophobic ketones by xerogel-immobilized W110A secondary alcohol dehydrogenase from Thermoanaerobacter ethanolicus (TeSADH) in organic solvents affords their S-configured alcohols in yields comparable with those achieved by using the free enzyme, and, in some cases, with higher enantioselectivities. R = phenyl-ring-containing substituent. (Figure Presented).
- Musa, Musa M.,Ziegelmann-Fjeld, Karla I.,Vieille, Claire,Zeikus, J. Gregory,Phillips, Robert S.
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p. 3091 - 3094
(2008/03/13)
-
- Magnetically separable Pd catalyst for highly selective epoxide hydrogenolysis under mild conditions
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A magnetically separable palladium catalyst was synthesized simply through a sol-gel process incorporating palladium nanoparticles and superparamagnetic iron oxide nanoparticles in aluminum oxyhydroxide matrix, which is highly active and selective for epoxide hydrogenolysis at room temperature under 1 atm H 2. The catalyst was recycled for 25 times without loss of the activity.
- Kwon, Min Serk,Park, In Soo,Jang, Jum Suk,Lee, Jae Sung,Park, Jaiwook
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p. 3417 - 3419
(2008/02/12)
-
- SULPHONYLATED DIPHENYLETHYLENEDIAMINES, METHOD FOR THEIR PREPARATION AND USE IN TRANSFER HYDROGENATION CATALYSIS
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A diamine of formula (I) is described, in which A is hydrogen or a saturated or unsaturated C1-C20 alkyl group or an aryl group; B is a substituted or unsubstituted C1-C20 alkyl, cycloalkyl, alkaryl, alkaryl or aryl group or an alkylamino group and at least one of X1, X2, Y1, Y2 or Z is a C1-C10 alkyl, cycloalkyl, alkaryl, aralkyl or alkoxy substituting group. The chiral diamine may be used to prepare catalysts suitable for use in transfer hydrogenation reactions.
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-
Page/Page column 9-10
(2008/06/13)
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- Removal of the acyl donor residue allows the use of simple alkyl esters as acyl donors for the dynamic kinetic resolution of secondary alcohols
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The dynamic kinetic resolution of secondary alcohols using a lipase and a ruthenium catalyst as developed by Baeckvall required some improvements to make it suitable for its use in an industrial process. The use of p-chlorophenyl acetate as acyl donor is not desirable in view of the toxicity of the side product. We herein report that simple alkyl esters can be used as acyl donors if the alcohol or ketone residue formed during the enzymatic acylation is continuously removed during the reaction. The addition of a ketone speeds up the racemisation process and allowed us to reduce the amounts of enzyme and ruthenium catalyst. The scope of this method was explored and a suitable range of acyl donors found. Various benzylic and aliphatic alcohols were reacted using isopropyl butyrate or methyl phenylacetate as acyl donor and in most cases the ester was isolated in >95% yield and 99% ee. Furthermore, it was demonstrated that the alcohol by-products of the enzymatic resolution could be used as the hydrogen source in the asymmetric reductive transesterification of ketones.
- Verzijl, Gerard K.M.,De Vries, Johannes G.,Broxterman, Quirinus B.
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p. 1603 - 1610
(2007/10/03)
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- Combined ruthenium(II) and lipase catalysis for efficient dynamic kinetic resolution of secondary alcohols. Insight into the racemization mechanism
-
Pentaphenylcyclopentadienyl ruthenium complexes (3) are excellent catalysts for the racemization of secondary alcohols at ambient temperature. The combination of this process with enzymatic resolution of the alcohols results in a highly efficient synthesis of enantiomerically pure acetates at room temperature with short reaction times for most substrates. This new reaction was applied to a wide range of functionalized alcohols including heteroaromatic alcohols, and for many of the latter, enantiopure acetates were efficiently prepared for the first time via dynamic kinetic resolution (DKR). Different substituted cyclopentadienyl ruthenium complexes were prepared and studied as catalysts for racemization of alcohols. Pentaaryl-substituted cyclopentadienyl complexes were found to be highly efficient catalysts for the racemization. Substitution of one of the aryl groups by an alkyl group considerably slows down the racemization process. A study of the racemization of (S)-1-phenylethanol catalyzed by ruthenium hydride η5-Ph5CpRu(CO) 2H (8) indicates that the racemization takes place within the coordination sphere of the ruthenium catalyst. This conclusion was supported by the lack of ketone exchange in the racemization of (S)-1-phenylethanol performed in the presence of p-tolyl methyl ketone (1 equiv), which gave 1% of 1-(p-tolyl)ethanol. The structures of ruthenium chloride and iodide complexes 3a and 3c and of ruthenium hydride complex 8 were confirmed by X-ray analysis.
- Martin-Matute, Belen,Edin, Michaela,Bogar, Krisztian,Kaynak, F. Betuel,Baeckvall, Jan-E.
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p. 8817 - 8825
(2007/10/03)
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- Preparative asymmetric reduction of ketones in a biphasic medium with an (S)-alcohol dehydrogenase under in situ-cofactor-recycling with a formate dehydrogenase
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The substrate range of a novel recombinant (S)-alcohol dehydrogenase from Rhodococcus erythropolis is described. In addition, an enzyme-compatible biphasic reaction medium for the asymmetric biocatalytic reduction of ketones with in situ-cofactor regeneration has been developed. Thus, reductions of poorly water soluble ketones in the presence of the alcohol dehydrogenase from R. erythropolis and a formate dehydrogenase from Candida boidinii can be carried out at higher substrate concentrations of 10-200 mM. The resulting (S)-alcohols were formed with moderate to good conversion rates, and with up to >99% ee.
- Gr?ger, Harald,Hummel, Werner,Rollmann, Claudia,Chamouleau, Francoise,Hüsken, Hendrik,Werner, Helge,Wunderlich, Christine,Abokitse, Kofi,Drauz, Karlheinz,Buchholz, Stefan
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p. 633 - 640
(2007/10/03)
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