- Evaluation of Oxetan-3-ol, Thietan-3-ol, and Derivatives Thereof as Bioisosteres of the Carboxylic Acid Functional Group
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The oxetane ring serves as an isostere of the carbonyl moiety, suggesting that oxetan-3-ol may be considered as a potential surrogate of the carboxylic acid functional group. To investigate this structural unit, as well as thietan-3-ol and the corresponding sulfoxide and sulfone derivatives, as potential carboxylic acid bioisosteres, a set of model compounds has been designed, synthesized, and evaluated for physicochemical properties. Similar derivatives of the cyclooxygenase inhibitor, ibuprofen, were also synthesized and evaluated for inhibition of eicosanoid biosynthesis in vitro. Collectively, the data suggest that oxetan-3-ol, thietan-3-ol, and related structures hold promise as isosteric replacements of the carboxylic acid moiety.
- Lassalas, Pierrik,Oukoloff, Killian,Makani, Vishruti,James, Michael,Tran, Van,Yao, Yuemang,Huang, Longchuan,Vijayendran, Krishna,Monti, Ludovica,Trojanowski, John Q.,Lee, Virginia M.-Y.,Kozlowski, Marisa C.,Smith, Amos B.,Brunden, Kurt R.,Ballatore, Carlo
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Read Online
- Synthesis of Ibuprofen intermediate using alcoholic silver nanoparticles and its kinetics: A greener approach towards drug synthesis
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Silver nanoparticles (AgNPs) were prepared and tested for the activity in the catalytic reduction of 4-nitrophenol to 4-aminophenol showing to be exceptionally active. Further, using AgNPs we catalytically synthesized 1-(4-isobutylphenyl)ethanol which is
- Pawar, Sandeep J.,Patil, Shivkumar Y.,Mahulikar, Pramod P.,Zope, Vishvanath S.
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Read Online
- Heterogeneous selective catalytic hydrogenation of aryl ketones to alcohols without additives
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A selective hydrogenation of different aryl ketones can be obtained by using a heterogeneous copper catalyst under very mild experimental conditions, namely 90°C and 1 atm of hydrogen, without using any kind of additive or poisoning agent.
- Zaccheria, Federica,Ravasio, Nicoletta,Psaro, Rinaldo,Fusi, Achille
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Read Online
- CONTINUOUS FLOW SYNTHESIS OF IBUPROFEN
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This disclosure generally relates to methods of making ibuprofen, naproxen, and derivatives thereof. This disclosure also generally relates to compounds made by the disclosed methods. This abstract is intended as a scanning tool for purposes of searching in the particular art and is not intended to be limiting of the present invention.
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- Preparation method of aryl propionic acid compound
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The invention provides a preparation method of an aryl propionic acid compound, wherein the preparation method comprises the following steps: carrying out acetylation reaction on substituted aryl benzene to obtain aryl acetophenone; carrying out hydrogenation reduction reaction on alpha-substituted aryl ethyl ketone to obtain alpha-substituted aryl ethanol; and in an acidic solution, introducing carbon monoxide gas into the alpha-substituted aryl ethanol, and carrying out a carbonylation reaction under the co-catalytic action of a main catalyst and a cocatalyst to obtain the aryl propionic acid compound, wherein the cocatalyst has the following structural formula described in the specification, R1 is one of hydrogen and a substituted carboxylic acid group, and R2 is one of hydrogen, halogen, substituted or unsubstituted C1-C12 alkyl, substituted or unsubstituted C1-C6 alkoxy, substituted or unsubstituted C3-C12 naphthenic base, substituted carbonyl containing C6-C24 aryl or substitutedaryl, substituted carbonyl containing C3-C12 heterocyclic radical or substituted heterocyclic radical, phenyl, substituted phenyl, naphthyl and substituted naphthyl.
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- A General Method for Photocatalytic Decarboxylative Hydroxylation of Carboxylic Acids
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A general and practical method for decarboxylative hydroxylation of carboxylic acids was developed through visible light-induced photocatalysis using molecular oxygen as the green oxidant. The addition of NaBH4 to in situ reduce the unstable peroxyl radical intermediate much broadened the substrate scope. Different sp3 carbon-bearing carboxylic acids were successfully employed as substrates, including phenylacetic acid-type substrates, as well as aliphatic carboxylic acids. This transformation worked smoothly on primary, secondary, and tertiary carboxylic acids.
- Khan, Shah Nawaz,Zaman, Muhammad Kashif,Li, Ruining,Sun, Zhankui
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p. 5019 - 5026
(2020/05/01)
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- One-pot method for the synthesis of 1-aryl-2-aminoalkanol derivatives from the corresponding amides or nitriles
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We have identified a novel one-pot method for the synthesis of β-amino alcohols, which is based on C-H bond hydroxylation at the benzylic α-carbon atom with a subsequent nitrile or amide functional group reduction. This cascade process uses molecular oxygen as an oxidant and sodium bis(2-methoxyethoxy)aluminum hydride as a reductant. The substrate scope was examined on 30 entries and, although the respective products were provided in moderate yields only, the above simple protocol may serve as a direct and powerful entry to the sterically congested 1,2-amino alcohols that are difficult to prepare by other routes. The plausible mechanistic rationale for the observed results is given and the reaction was applied to a synthesis of a potentially bioactive target. This journal is
- Bobal, Pavel,Otevrel, Jan,Svestka, David
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p. 25029 - 25045
(2020/07/14)
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- Pyridine mediated transition-metal-free direct alkylation of anilines using alcohols: via borrowing hydrogen conditions
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Herein, we report pyridine and other similar azaaromatics as efficient biomimetic hydrogen shuttles for a transition-metal-free direct N-alkylation of aryl and heteroaryl amines using a variety of benzylic and straight chain alcohols. Mechanistic studies including deuterium labeling and the isolation of dihydro-intermediates of the benzannulated pyridine confirmed the role of pyridine and a borrowing hydrogen process operating in these reactions. In addition, we have extended this methodology for the development of dehydrogenative synthesis of quinolines and indoles, as well as the transfer hydrogenation of ketones. This journal is
- Pothikumar, Rajagopal,Bhat, Venugopal T,Namitharan, Kayambu
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supporting information
p. 13607 - 13610
(2020/11/17)
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- Synthesis of Substituted Benzaldehydes via a Two-Step, One-Pot Reduction/Cross-Coupling Procedure
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The synthesis of functionalized (benz)aldehydes, via a two-step, one-pot procedure, is presented. The method employs a stable aluminum hemiaminal as a tetrahedral intermediate, protecting a latent aldehyde, making it suitable for subsequent cross-coupling with (strong nucleophilic) organometallic reagents, leading to a variety of alkyl and aryl substituted benzaldehydes. This very fast methodology also facilitates the effective synthesis of a 11C radiolabeled aldehyde. Aluminum-ate complexes enable transmetalation of alkyl fragments onto palladium and subsequent cross-coupling.
- Heijnen, Dorus,Helbert, Hugo,Luurtsema, Gert,Elsinga, Philip H.,Feringa, Ben L.
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supporting information
p. 4087 - 4091
(2019/06/14)
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- Pyridine-Stabilized Rhodium Nanoparticles in Ionic Liquids as Selective Hydrogenation and Transfer Hydrogenation Catalysts
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Rhodium nanoparticles (RhNPs) stabilized with pyridine-based ligands in the ionic liquid [BMIM][BF4] (RhNPs-I to III) were synthesized from the organometallic precursor [Rh(μ-OMe)COD]2 under dihydrogen pressure. The pyridine-stabilized RhNPs showed smaller size compared to the ligand free RhNPs-V and presented higher activity and selectivity in the hydrogenation of acetophenone to 1-phenylethanol. In the case of pyridine-capped RhNPs-I, the system was reused for several runs without loss of activity and selectivity. Nitrobenzene was reduced to aniline with dihydrogen in the presence of RhNPs-I with moderate activity. When the hydrogen source was formic acid-Et3N azeotrope (transfer hydrogenation) the reaction was completed within minutes with high selectivity. Under transfer hydrogenation conditions, it was possible to apply the catalytic system RhNPs-I in multistep processes for the generation of substituted arylic amines through the reductive N-alkylation of nitrobenzene and benzaldehyde; and the synthesis of substituted pyrroles through the nitroarene reduction/Paal-Knorr condensation.
- Serrano-Maldonado, Alejandro,Martin, Erika,Guerrero-Ríos, Itzel
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supporting information
(2019/04/26)
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- Enantiocomplementary decarboxylative hydroxylation combining photocatalysis and whole-cell biocatalysis in a one-pot cascade process
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Designing a green, highly efficient and stereoselective catalytic system to generate valuable enantioenriched products is a long-standing goal in green chemistry. Here, we report a one-pot cascade combining photocatalysts with (R)- or (S)-selective ketoreductases for the decarboxylative carbonylation of carboxylic acids and the subsequent bioreduction to generate valuable chiral alcohols. Using this approach, various chiral alcohols with complementary (R)- or (S)-configurations were prepared with good yields (up to 93%) and excellent stereoselectivity (up to 99% ee). Such a photochemo-enzymatic one-pot whole-cell process combines the advantages of both photocatalysts and enzyme catalysts and provides a mild, green, metal-free and highly stereoselective alternative in asymmetric decarboxylative hydroxylation reactions.
- Xu, Jian,Arkin, Mamatjan,Peng, Yongzhen,Xu, Weihua,Yu, Huilei,Lin, Xianfu,Wu, Qi
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supporting information
p. 1907 - 1911
(2019/04/27)
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- Method for synthesizing alkyne through catalytic asymmetric cross coupling (by machine translation)
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The invention belongs to the field of, asymmetric synthesis, and discloses a method for catalyzing asymmetric cross- coupling to synthesize: an alkyne, and the L method comprises, the following steps, of A: preparing B a cuprous, salt and C a: ligand; preparing a catalyst; adding a base; reacting the compound with the compound with the compound; and reacting the compound with the compound. Of these, one of them, X is selected from the group consisting of, R halogens. 1 Optionally substituted heteroarylsulfonylcyanamide groups selected from the, group consisting, of optionally substituted, phenyl groups In-flight vehicle, R6 Trialkyl silyl groups or alkyl radicals, R2 Cycloalkyl radicals optionally substituted with an, optionally substituted alkyl, (CH radical2 )n R4 Multi,layer chain, n=0-10,R saw blade4 A group selected, from, the group consisting of phenyl, alkenyl, aralkynyls, noonyloxy,and, noonylsulfonylsulfonylsulfonylsulfonylsulfonylsulfonylsulfonylsulfonylsulfonylsulphonylsulphonylsulphonylsulphonylsulphonylsulphonylsulphonylsulphonylsulphonylsulphonylphenyl disiloxy-radicals. R3 A ligand, selected from hydrogen or any of the functional groups, is selected from the group consisting of, hydrogen and any L other functional group. The method, R disclosed by the, A invention has the, advantages of good catalytic, R ’ effect, wide application range. and high catalytic efficiency, and the, method disclosed by the, invention has the. advantages of good catalytic effect, wide application range and high catalytic efficiency. (by machine translation)
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Paragraph 0983-0987
(2020/01/12)
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- METHODS OF ACYLATION WITH AN IONIC LIQUID CATALYZING MEDIUM
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Described herein are methods of acylating an aryl substrate comprising combining a substituted aryl substrate with an acylating agent in the presence of a catalyzing medium, thereby acylating the substituted aryl substrate in the para position, wherein the catalyzing medium is an ionic liquid comprising at least one cation and at least one metal halide anion.
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- Hypervalent iodine(III)-mediated decarboxylative acetoxylation at tertiary and benzylic carbon centers
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The decarboxylative acetoxylation of carboxylic acids using a combination of PhI(OAc)2 and I2 in a CH2Cl2/AcOH mixed solvent is reported. The reaction was successfully applied to two types of carboxylic acids containing an α-quaternary and a benzylic carbon center under mild reaction conditions. The resulting acetates were readily converted into the corresponding alcohols by hydrolysis.
- Kiyokawa, Kensuke,Okumatsu, Daichi,Minakata, Satoshi
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p. 1046 - 1050
(2019/11/11)
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- Abiotic degradation and environmental toxicity of ibuprofen: Roles of mineral particles and solar radiation
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The growing medical and personal needs of human populations have escalated release of pharmaceuticals and personal care products into our natural environment. This work investigates abiotic degradation pathways of a particular PPCP, ibuprofen, in the presence of a major mineral component of soil (kaolinite clay), as well as the health effects of the primary compound and its degradation products. Results from these studies showed that the rate and extent of ibuprofen degradation is greatly influenced by the presence of clay particles and solar radiation. In the absence of solar radiation, the dominant reaction mechanism was observed to be the adsorption of ibuprofen onto clay surface where surface silanol groups play a key role. In contrast, under solar radiation and in the presence of clay particles, ibuprofen breaks down to several fractions. The decay rates were at least 6-fold higher for irradiated samples compared to those of dark conditions. Toxicity of primary ibuprofen and its secondary residues were tested on three microorganisms: Bacillus megaterium, Pseudoaltermonas atlantica; and algae from the Chlorella genus. The results from the biological assays show that primary PPCP is more toxic than the mixture of secondary products. Overall, however, biological assays carried out using only 4-acetylbenzoic acid, the most abundant secondary product, show a higher toxic effect on algae compared to its parent compound.
- Rubasinghege, Gayan,Gurung, Rubi,Rijal, Hom,Maldonado-Torres, Sabino,Chan, Andrew,Acharya, Shishir,Rogelj, Snezna,Piyasena, Menake
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- Improving Catalytic Hydrogenation Performance of Pd Nanoparticles by Electronic Modulation Using Phosphine Ligands
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Tuning the activity and selectivity of metal nanoparticles (NPs) is a long-term pursuit in the field of catalysis. Herein, we report successfully improving both the activity and chemoselectivity of Pd NPs (1.1 nm) with triphenylphosphine (PPh3) cross-linked in the nanopore of FDU-12. The electron-donating effect of PPh3 increases the surface electronic density of Pd NPs and weakens the Pd-H bond, as evidenced by the results of XPS, in situ FT-IR adsorption of CO, and H2-D2 exchange reactions. Consequently, Pd NPs modified with PPh3 obtain >99% selectivity to 1-phenylethanol in acetophenone hydrogenation and 94% selectivity to styrene in phenylacetylene hydrogenation. Furthermore, the activity of Pd NPs is enhanced and suppressed by PPh3, respectively, in the hydrogenation of electrophilic nitro compounds and nucleophilic carbonyl substrates. Our primary results shed some light on judiciously choosing organic ligands for modifying the catalytic performance of metal NPs toward specific chemical transformations.
- Guo, Miao,Li, He,Ren, Yiqi,Ren, Xiaomin,Yang, Qihua,Li, Can
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p. 6476 - 6485
(2018/06/18)
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- Photocatalytic Decarboxylative Hydroxylation of Carboxylic Acids Driven by Visible Light and Using Molecular Oxygen
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This paper discloses the first example of photocatalytic direct decarboxylative hydroxylation of carboxylic acids. It enables the conversion of a variety of readily available carboxylic acids to alcohols in moderate to high yields. This unprecedented protocol is accomplished under extremely mild reaction conditions using molecular oxygen (O2) as a green oxidant and using visible light as a driving force.
- Song, Hai-Tao,Ding, Wei,Zhou, Quan-Quan,Liu, Jing,Lu, Liang-Qiu,Xiao, Wen-Jing
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p. 7250 - 7255
(2016/08/30)
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- Investigations in sono-enzymatic degradation of ibuprofen
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The drug ibuprofen (IBP) appears frequently in the wastewater discharge from pharmaceutical industries. This paper reports studies in degradation of IBP employing hybrid technique of sono-enzymatic treatment. This paper also establishes synergy between individual mechanisms of enzyme and sonolysis for IBP degradation by identification of degradation intermediates, and Arrhenius & thermodynamic analysis of the experimental data. Positive synergy between sonolysis and enzyme treatment is attributed to formation of hydrophilic intermediates during degradation. These intermediates form due to hydroxylation and oxidation reactions induced by radicals formed during transient cavitation. Activation energy and enthalpy change in sono-enzymatic treatment are lower as compared to enzyme treatment, while frequency factor and entropy change are higher as compared to sonolysis. Degradation of IBP in sono-enzymatic treatment is revealed to be comparable with other hybrid techniques like photo-Fenton, sono-photocatalysis, and sono-Fenton.
- Chakma, Sankar,Moholkar, Vijayanand S.
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p. 485 - 494
(2015/11/24)
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- Simultaneous identification of Fenton degradation by-products of diclofenac, ibuprofen and ketoprofen in aquatic media by comprehensive two-dimensional gas chromatography coupled with mass spectrometry
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Diclofenac, ibuprofen and ketoprofen are anti-inflammatory drugs intensively used both in human and animal treatment. Due to their high stability these compounds are partially removed by wastewater treatment plants and from this reason the development of some alternative treatments such as advanced oxidative processes are necessary. The main problems in the optimization of an advanced oxidative process rise from the difficulties which appear in the identification of degradation by-products necessary for the establishment of degradation pathway. In this paper a developed method for the simultaneous identification of Fenton degradation by-products of the three above mentioned pharmaceuticals is presented. The obtained results show the comprehensive two-dimensional gas chromatography coupled with mass spectrometry as a proper method for the analysis of the complex mixture of compounds resulted from the Fenton degradation process. Moreover, some compounds never mentioned in the scientific literature were identified. (Chemical Equation Presented).
- Beldean-Galea, Mihail Simion,Coman, Virginia,Copaciu, Florina,Thiébaut, Didier,Vial, Jér?me
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p. 1021 - 1027
(2015/07/15)
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- Photolysis and photocatalysis of ibuprofen in aqueous medium: Characterization of by-products via liquid chromatography coupled to high-resolution mass spectrometry and assessment of their toxicities against Artemia Salina
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The degradation of the pharmaceutical compound ibuprofen (IBP) in aqueous solution induced by direct photolysis (UV-A and UV-C radiation) and photocatalysis (TiO2/UV-A and TiO2/UV-C systems) was evaluated. Initially, we observed that whereas photocatalysis (both systems) and direct photolysis with UV-C radiation were able to cause an almost complete removal of IBP, the mineralization rates achieved for all the photodegradation processes were much smaller (the highest value being obtained for the TiO 2/UV-C system: 37.7%), even after an exposure time as long as 120 min. Chemical structures for the by-products formed under these oxidative conditions (11 of them were detected) were proposed based on the data from liquid chromatography coupled to high-resolution mass spectrometry (LC-HRMS) analyses. Taking into account these results, an unprecedented route for the photodegradation of IBP could thus be proposed. Moreover, a fortunate result was achieved herein: tests against Artemia salina showed that the degradation products had no higher ecotoxicities than IBP, which possibly indicates that the photocatalytic (TiO2/UV-A and TiO2/UV-C systems) and photolytic (UV-C radiation) processes can be conveniently employed to deplete IBP in aqueous media. Copyright
- Da Silva, Julio Cesar Cardoso,Teodoro, Janaina Aparecida Reis,Afonso, Robson Jose De Cassia Franco,Aquino, Sergio Francisco,Augusti, Rodinei
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p. 145 - 153
(2014/02/14)
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- Silicon nanowires as photoelectrodes for carbon dioxide fixation
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Lights on: When illuminated, p-type Si nanowires donate photogenerated electrons to aromatic ketones, producing reactive radicals that can harvest CO2 to yield α-hydroxy acids (see scheme). The reaction scheme closely resembles that of natural photosynthesis and gives up to 98 % yield and selectivity. Products obtained by this reaction include important precursors for nonsteroidal anti-inflammatory drugs, such as ibuprofen and naproxen. Copyright
- Liu, Rui,Yuan, Guangbi,Joe, Candice L.,Lightburn, Thomas E.,Tan, Kian L.,Wang, Dunwei
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p. 6709 - 6712
(2012/09/22)
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- MgCl2-accelerated addition of functionalized organozinc reagents to aldehydes, ketones, and carbon dioxide
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Figure Presented Pump it up! The sluggish reactivity of organozinc reagents in additions to aldehydes, ketones, and CO2 can be increased by MgCl2, which is usually generated in the preparation of the zinc reagent. The direct reaction with CO2, in particular, opens an expeditious route to phenylacetic acid derivatives, as demonstrated in a short synthesis of ibuprofen (see scheme).
- Metzger, Albrecht,Bernhardt, Sebastian,Manolikakes, Georg,Knochel, Paul
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supporting information; experimental part
p. 4665 - 4668
(2010/08/19)
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- NOVEL PROTEIN TYROSINE PHOSPHATASE - IB INHIBITORS
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The present invention relates to the novel compounds of the general formula (I), wherein the symbols are same as described in specification, their pharmaceutically acceptable salts, their tautomeric forms, their stereoisomers, pharmaceutical compositions containing them, to process and intermediates for the preparation of the above said compounds, having the utility of these compounds in medicine and to methods for their therapeutic use, and their use in the treatment of diabetes and related diseases.
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Page/Page column 55
(2009/10/22)
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- Tuning the support adsorption properties of Pd/SiO2 by silylation to improve the selective hydrogenation of aromatic ketones
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Silylation of Pd/SiO2 catalysts increases the selectivity toward alcohols in the reduction of aromatic ketones. This work demonstrates that the selectivity is directly related to the adsorption strength of the alcohol on the surface of the support relative to the adsorption strength of the ketone. This observation can be explained by interaction of the support coverage with the metal coverage. Silylation yields a more hydrophobic support, on which the aromatic alcohol adsorbs more weakly relative to the ketone, in turn decreasing the amount of the alcohol adsorbed on the metal and thus suppressing the consecutive reduction of the alcohol. Silylation was carried out by using di-alkyl (dichlorodimethylsilane) and tri-alkyl (hexamethyldisilazane and hexamethyldisilane) silylating agents. Hexamethyldisilazane provided to be the most effective agent in terms of incorporation of methyl groups, catalyst hydrophobicity, and stability. Selective hydrogenation of 4-isobutyl acetophenone (4-IBAP) to 4-isobutylphenyl ethanol (4-IBPE) revealed that not only was the fresh hexamethyldisilazane-silylated Pd/SiO2 catalyst more selective than the untreated catalyst, but also the silylated catalyst was much more selective after a deactivation-regeneration cycle than the untreated Pd/SiO2 catalyst. The change in selectivity can be explained by a change in the relative adsorption strength of 4-IBPE over 4-IBAP on silylation.
- Quintanilla,Bakker,Kreutzer,Moulijn,Kapteijn
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scheme or table
p. 55 - 63
(2009/02/07)
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- Transfer hydrogenation of carbonyl compounds catalyzed by ruthenium nanoparticles stabilized on nanocrystalline magnesium oxide by ionic liquids
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Transfer hydrogenation of various carbonyl compounds was achieved in excellent yields by ruthenium nanoparticles stabilized on the nanocrystalline magnesium oxide by the incorporation of choline hydroxide, a basic ionic liquid. The procedure is simple, efficient and the catalyst can be recycled five times.
- Lakshmi Kantam,Sudarshan Reddy,Pal, Ujjwal,Sreedhar,Bhargava
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supporting information; experimental part
p. 2231 - 2235
(2009/10/06)
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- Highly dispersed ruthenium hydroxide supported on titanium oxide effective for liquid-phase hydrogen-transfer reactions
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Supported ruthenium hydroxide catalysts (Ru(OH)x/support) were prepared with three different TiO2 supports (anatase TiO2 (TiO2(A), BET surface area: 316 m2g-1), anatase TiO2 (TiO2(B), 73m2 g-1), and rutile TiO2 (TiO2(C), 3.2 m2 g-1)), as well as an Al2O3 support (160 m2g -1). Characterizations with X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), electron spin resonance (ESR), and X-ray absorption fine structure (XAFS) showed the presence of monomeric ruthenium(III) hydroxide and polymeric ruthenium(III) hydroxide species. Judging from the coordination numbers of the nearest-neighbor Ru atoms and the intensities of the ESR signals, the amount of monomeric hydroxide species increased in the order of Ru(OH)x x/ TiO2(C) x/Al2O3 x/ TiO 2(B) x/TiO2(A). These supported ruthenium hydroxide catalysts, especially Ru(OH)x/TiO2(A), showed high catalytic activities and selectivities for liquid-phase hydrogen-transfer reactions, such as racemization of chiral secondary alcohols and the reduction of carbonyl compounds and allylic alcohols. The catalytic activities of Ru(OH)x/TiO2(A) for these hydrogen-transfer reactions were at least one order of magnitude higher than those of previously reported heterogeneous catalysts, such as Ru(OHx/Al2O 3. These catalyses were truly heterogeneous, and the catalysts recovered after the reactions could be reused several times without loss of catalytic performance. The reaction rates monotonically increased with an increase in the amount of monomeric ruthenium hydroxide species, which suggests that the monomeric species are effective for these hydrogen-transfer reactions.
- Yamaguchi, Kazuya,Koike, Takeshi,Kim, Jung Won,Ogasawara, Yoshiyuki,Mizuno, Noritaka
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scheme or table
p. 11480 - 11487
(2009/12/03)
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- Selective transfer hydrogenation of carbonyl compounds by ruthenium nanoclusters supported on alkali-exchanged zeolite beta
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Selective transfer hydrogenation of aromatic ketones and β-keto esters to the corresponding alcohols was achieved by using ruthenium nanoclusters supported on alkali-exchanged zeolite beta catalyst. The high activity and selectivity of the catalyst is due to the presence of highly dispersed ruthenium clusters in combination with the large number of Bronsted acidic sites of zeolite.
- Kantam, M. Lakshmi,Rao, B. Purna Chandra,Choudary,Sreedhar
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p. 1970 - 1976
(2007/10/03)
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- Sulfonic acids, their derivatives and pharmaceutical compositions containing them
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Selected sulfonic acids, their derivatives and pharmaceutical compositions containing such compounds are useful in inhibiting the chemotactic activation of neutrophils (PMN leukocytes) induced by the interaction of Interleukin-8 (IL-8) with CXCR1 and CXCR2 membrane receptors. The compounds are used for the prevention and treatment of pathologies deriving from said activation. Notably, the selected sulfonic acids and their derivativas are devoid of cyclo-oxygenase inhibition activity and are particularly useful in the treatment of neutrofil-dependent pathologies such as psoriasis, ulcerative colitis, melanoma, chronic obstructive pulmonary disease (COPD), bullous pemphigoid, rheumatoid arthritis, idiopathic fibrosis, glomerulonephritis and in the prevention and treatment of damages caused by ischemia and reperfusion.
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- Synthesis of E-aryl ethenesulfonamides: A simple one-pot, two-step procedure from 1-hydroxy-1-arylalkanes
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The unusual reactivity of 1-phenyl-1-ethane-sulfonic acid in thionyl chloride was investigated. Mechanistic considerations led us to set up a new and efficient synthesis of E-arylethenesulfonamides starting from 1-hydroxy-1-arylalkanes. The easy availability of the starting materials and the straightforward, one-pot procedure make this process an attractive method for the preparation of these compounds currently largely employed in chemical and pharmaceutical fields.
- Aramini, Andrea,Cesta, Maria C.,Coniglio, Silvia,Bijani, Christian,Colagioia, Sandro,D'Elia, Valerio,Allegretti, Marcello
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p. 7911 - 7914
(2007/10/03)
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- 4-(Benzoylindolizinyl)butyric acids; novel nonsteroidal inhibitors of steroid 5α-reductase. III
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A novel series of indolizinebutyric acids with various benzoyl substituents was synthesized to develop nonsteroidal inhibitors of steroid 5α-reductase, and the structure-activity relationships in this series were studied. We previously reported the structure-activity relationships in a series of indolebutyric acids as well as the discovery of the novel nonsteroidal 5α-reductase inhibitor, FK143. We have now made other modifications to this compound to improve in vivo inhibitory activity. By altering the heterocyclic nucleus and changing the benzoyl substituent we have succeeded in identifying the strongly active compound, FK687, (S)-4-[1-[4-[[1-(4-isobutylphenyl)butyl]oxy]benzoyl]indolizin-3-yllbutyric acid, which displays strong in vitro inhibitory activity against the human enzyme and in vivo inhibitory activity against the castrated young rat model. This compound should be a useful agent for the treatment of benign prostatic hyperplasia.
- Sawada,Okada,Kuroda,Watanabe,Sawada,Tanaka
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p. 799 - 813
(2007/10/03)
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- Hydrogen-transfer catalyzed by half-sandwich Ru(II) aminophosphine complexes
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The syntheses of and catalytic studies on some Ru(II) complexes bearing the aminophosphine ligands N,N-dimethyl-2-diphenylphosphinoethylamine (PN), optically pure (RC,Spl)-2-{1-(N,N-dimethylamino)ethyl}-1- diphenylphosphinoferrocene(PPFA), and N,N-dimethyl-2-diphenylphosphinoaniline (DBD) are described, [RuCp(CH3CN)3]+ reacts with these ligands to give the cationic complexes [RuCp(PN-κN,κP)(CH3CN)]+ (1a), [(SRu,RC,Spl)-RuCp(PPFA-κN,κP) (CH3CN)]+ (1b), and [RuCp(DBD-κN,κP)(CH3CN)]+ (1c), respectively, in high yields. From these, in turn, the residual CH3CN ligand can be replaced by Br- upon addition of NEt4Br in CH2Cl2, resulting in the formation of the neutral complexes RuCp(PN)Br (2a), (SRu,RC,Spl)-RuCp(PPFA)Br (2b), and RuCp(DBD)Br (2c), again in good yields. Similarly, [Ru(η6-p-cymene)Cl2]2 reacts with 1 equiv. of PN or PPFA to give Ru(η6-p-cymene)(PN-κP)Cl2 (3a) and Ru(η6-p-cymene)(PPFA-κP)Cl2 (3b). Furthermore, treatment of 3 with TlCF3SO3 in THF at room temperature affords the cationic complexes [Ru(η6-p-cymene)(PN-κN,κP)Cl]CF3SO 3 (4a) and [(RRu,RC,Spl)-Ru (η6-p-cymene)-(PPFA-κN,κP)Cl]CF3SO 3 (4b). The absolute configuration at the metal center of 2b and 4b′ (BPh4- salt of 4b) was determined by X-ray crystallography. Catalytic studies were performed with the racemic complexes 1a, 2a, 2c, and 4a and the diastereopure complexes 1b, 2b, and 4b. All of these proved to be excellent precatalysts for the transfer hydrogenation of acetophenone and derivatives thereof, and cyclohexanone. With the enantiomerically pure systems 2b and 4b, only racemic products were obtained. This testifies to the hemilabile nature of the aforementioned aminophosphine ligands giving transient κ-P-bonding coordination. Since diastereoface selection of incoming substrates is based on the planar chirality of the ferrocene moiety, rather than the metal centered chirality, no enantioselective reaction takes place.
- Standfest-Hauser,Slugovc,Mereiter,Schmid,Kirchner,Xiaoc,Weissensteiner
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p. 2989 - 2995
(2007/10/03)
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- Biomimetic oxidation of ibuprofen with hydrogen peroxide catalysed by Horseradish peroxidase (HRP) and 5,10,15,20- tetrakis-(2',6'-dichloro-3'- sulphonatophenyl)porphyrinatoiron(III) and manganese(III) hydrates in AOT reverse micelles
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The oxidation of ibuprofen with H2O2 catalysed by Horseradish peroxidase (HRP), Cl8TPPS4Fe(III)(OH2)2 and Cl8TPPS4Mn(III)(OH2)2 in AOT reverse micelles gives 2-(4'-isobutyl-phenyl)ethanol (5) and p-isobutyl acetophenone (6) in moderate yields. The reaction of ibuprofen (2) with H2O2 catalysed by HRP form carbon radicals by the oxidative decarboxylation, which on reaction with molecular oxygen to form hydroperoxy intermediate, responsible for the formation of the products 5 and 6. The yields of different oxidation products depend on the pH, the water to surfactant ratio (Wo), concentration of Cl8TPPS4Fe(III)(OH2)2 and Cl8TPPS4Mn(III)(OH2)2 and amount of molecular oxygen present in AOT reverse micelles. The formation of 2-(4'-isobutyl phenyl)ethanol (5) may be explained by the hydrogen abstraction from ibuprofen by high valent oxo- manganese(IV) radical cation, followed by decarboxylation and subsequent recombination of either free hydroxy radical or hydroxy iron(III)/manganese(III) porphyrins. The over-oxidation of 5 with high valent oxo-manganese, Mn(IV)radical cation intermediate form 6 in AOT reverse micelles by abstraction and recombination mechanism. (C) 1999 Elsevier Science Ltd.
- Chauhan,Sahoo
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p. 2629 - 2634
(2007/10/03)
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- Performances of homogeneous charge transfer catalysts in the electrocarboxylation of benzyl halides
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The electrocarboxylation of benzyl halides to the corresponding carboxylic acids performed by homogeneous charge transfer catalysts is reported here. The performances of selected ester derivatives of benzoic acid and of the three isomers of benzenedicarboxylic acid as catalysts are evaluated on the basis of the faradaic efficiency of the carboxylation and of the decomposition rate of the catalyst. The standard redox potentials of catalysts are related to the selectivity of the process. Rates of catalyst decomposition appear to be dependent on the molar ratio [halide]/[catalyst] and on the cathode material.
- Scialdone, Onofrio,Filardo, Giuseppe,Galia, Alessandro,Mantione, Davide,Silvestri, Giuseppe
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p. 800 - 806
(2007/10/03)
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- Steroid 5α-reductase: Comparative study of mechanism of inhibition by nonsteroids ONO-3805 and LY191704
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Two nonsteroids, ONO-3805 and LY191704, were evaluated as inhibitors of the human and rat 5α-reductases (5αR). ONO-3805 was prepared in a 12-step convergent synthesis. This compound is a potent inhibitor of the human and rat 5αRs, with more potent inhibition seen against the rat enzymes. The inhibition patterns of this compound were best fit to an uncompetitive model which suggests binding in a ternary complex with enzyme and NADP+. Apparent K(i) values of 27, 31, 1, and 0.5 nM versus testosterone were obtained with human type 1, human type 2, rat type 1, and rat type 2 5αR, respectively. Multiple inhibition studies with ONO-3805 and NADP+ support synergistic binding of these two inhibitors with all isozymes. LY191704 was also evaluated as an inhibitor of the human and rat 5αRs. This compound is a selective, competitive inhibitor of human type 1 5αR. Poor inhibition was observed with human type 2 and rat types 1 and 2 5αR.
- Harris, Georgianna S.,Ellsworth, Kenneth,Witzel, Bruce E.,Tolman, Richard L.
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p. 386 - 400
(2007/10/03)
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- Synthesis of α,α-disubstituted acetic acids using low-valent titanium
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Digalogenocarbenes generated using low-valent titanium (LVT) undergo a one-pot cycloaddition to diaryl, aryl alkyl or dialkyl ketones to give α,α-disubstituted acetic acids such as (R,S)-2-arylpropanoic acids.TiI4 proved most effective in this reaction for which the product yield was optimized by use of an excess of reducing agent.
- Garcia, Mariano,Campo, Carmen del,Llama, Emilio F.,Sinisterra, Jose V.
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p. 1771 - 1774
(2007/10/02)
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- OXIDATIVE DECARBOXYLATION OF CARBOXYLIC ACIDS BY IRON PORPHYRIN - IODOSYLBENZENE SYSTEM
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An iodosylbenzene - iron tetraarylporphyrin catalyst system decarboxylated α-aryl carboxylic acids and α,α,α-trisubstituted acetic acids efficiently to give the corresponding alcohol and carbonyl derivatives.
- Komuro, Masakatsu,Nagatsu, Yoshio,Higuchi, Tsunehiko,Hirobe, Masaaki
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p. 4949 - 4952
(2007/10/02)
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- Regiocontrolled Photooxygenation of Ibuprofen by Pyrimidopteridinetetrone- and Anthraquinone-Oxygen Systems
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Ibuprofen 4 underwent regiocontrolled photooxygenation on the propionic acid and isobutyl moieties in the presence of pyrimidopteridinetetrone 1- and anthraquinone 3- oxygen systems.
- Sako, Magoichi,Oyabu, Iwao,Hirota, Kosaku,Maki, Yoshifumi
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p. 601 - 602
(2007/10/02)
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- A new convenient reduction of aralkyl ketones to alcohols using Raney nickel-ammonium formate
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Various aralkyl ketones have been reduced to their corresponding alcohols in high yield using Raney Ni-HCO2NH4.
- Chen,Zhang,Yuan,Zhang
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p. 107 - 109
(2007/10/02)
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- Process for producing ibuprofen
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A method is provided for the preparation of ibuprofen by carbonylating 1-(4′-isobutylphenyl)ethanol (IBPE) with carbon monoxide in an acidic aqueous medium, e.g. containing at least 10% of water based on the weight of IBPE initially added, at a temperatur
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- Asymmetric Hydroformylation Catalyzed by Homogeneous and Polymer-Supported Platinum Complexes Containing Chiral Phosphine Ligands
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A complex of Pt(II) containing the chiral ligand (2S,4S)-N-(tert-butoxycarbonyl)-4-(diphenylphosphino)-2-pirrolidine in the presence of stannous chloride catalyzed the hydroformylation of a variety of prochiral olefins.Although the branched/normal (b/n) ratios were low (ca. 0.5), high ee's were achieved in the hydroformylation of styrene (70-80percent), p-isobutylstyrene (80percent), 2-vinylnaphthalene (77percent), 2-ethenyl-6-methoxynaphthalene (81percent), 4-(2-thienylcarbonyl)styrene (78percent), vinyl acetate(82percent), N-vinylphthalimide (73percent), methyl methacrylate (60percent), and norbornene (60percent).When the hydroformylation of styrene, 2-ethenyl-6-methoxynaphthalene, and vinyl acetate with PtCl2/SnCl2 was carried out in the presence of triethyl orthoformate, enantiomerically pure acetals were obtained.The hydroformylation in the presence of ethyl orthoformate also could be carried out by using a catalyst containing the PtCl2/SnCl2 complex bound to 60-μm beads composed of cross-linked polystyrene.
- Parrinello, Giovanni,Stille, J. K.
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p. 7122 - 7127
(2007/10/02)
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- Chiral (β-Aminoalkyl)phosphines. Highly Efficient Phosphine Ligands for Catalytic Asymmetric Grignard Cross-Coupling
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New chiral (β-aminoalkyl)phosphines, RCH(NMe2)CH2PPh2 , were prepared by starting with optically active amino acids.The phosphines were used as ligands for nickel-catalyzed asymmetric cross-coupling of 1-arylethyl Grignard reagents (ArMeCHMgCl) with vinyl bromide.Coupling products of over 70percent enantiomeric excess (ee) were obtained in the reaction with the ligand Phephos, Valphos, Ilephos, PhGlyphos, ChGlyphos, or t-Leuphos.A mechanism involving complexation of the magnesium atom in the Grignard reagent with the amino group on the (β-aminoalkyl)phosphine ligand is proposed to account for the high stereoselectivity.The asymmetric cross-coupling was applied to the synthesis of optically active 2-arylpropionic acids.
- Hayashi, Tamio,Konishi, Mitsuo,Fukushima, Motoo,Kanehira, Koichi,Hioki, Takeshi,Kumada, Makoto
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p. 2195 - 2202
(2007/10/02)
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