- Structure-Guided Regulation in the Enantioselectivity of an Epoxide Hydrolase to Produce Enantiomeric Monosubstituted Epoxides and Vicinal Diols via Kinetic Resolution
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Structure-guided microtuning of an Aspergillus usamii epoxide hydrolase was executed. One mutant, A214C/A250I, displayed a 12.6-fold enhanced enantiomeric ratio (E = 202) toward rac-styrene oxide, achieving its nearly perfect kinetic resolution at 0.8 M in pure water or 1.6 M in n-hexanol/water. Several other beneficial mutants also displayed significantly improved E values, offering promising biocatalysts to access 19 structurally diverse chiral monosubstituted epoxides (97.1 - ≥ 99% ees) and vicinal diols (56.2-98.0% eep) with high yields.
- Hou, Xiao-Dong,Hu, Bo-Chun,Hu, Die,Lei, Yu-Qing,Rao, Yi-Jian,Wu, Min-Chen,Zhang, Dong
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supporting information
p. 1757 - 1761
(2022/03/16)
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- Method for synthesizing chiral 1,2-diol compound
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The invention relates to a method for synthesizing a chiral 1,2-diol compound, which comprises the following steps: sequentially adding a cobalt catalyst, a ligand, alpha-hydroxy ketone, an organic solvent and silane into a reaction system at 20-30 DEG C in a nitrogen atmosphere, then stirring the mixture, and carrying out column chromatography separation on the obtained product to obtain the chiral 1,2-diol compound. The high-yield cobalt catalyst in the earth crust is used, meanwhile, cheap silane (PMHS, 500 g/298 yuan) is used as a reducing agent, the asymmetric reduction reaction of alpha-hydroxy ketone can be efficiently achieved under the mild condition, and the chiral 1,2-diol compound with high yield and optical activity is obtained. Moreover, through the creative labor of the inventor, the reaction yield can reach 99%, and meanwhile, the content of the target product in the generated reaction product is 99% (namely, the yield is 99%, 99% ee).
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Paragraph 0027; 0049-0052
(2021/07/21)
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- Catalytic Diastereo- and Enantioconvergent Synthesis of Vicinal Diamines from Diols through Borrowing Hydrogen
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We present herein an unprecedented diastereoconvergent synthesis of vicinal diamines from diols through an economical, redox-neutral process. Under cooperative ruthenium and Lewis acid catalysis, readily available anilines and 1,2-diols (as a mixture of diastereomers) couple to forge two C?N bonds in an efficient and diastereoselective fashion. By identifying an effective chiral iridium/phosphoric acid co-catalyzed procedure, the first enantioconvergent double amination of racemic 1,2-diols has also been achieved, resulting in a practical access to highly valuable enantioenriched vicinal diamines.
- Feng, Wei,Gao, Taotao,Lau, Kai Kiat,Lin, Yamei,Pan, Hui-Jie,Yang, Binmiao,Zhao, Yu
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supporting information
p. 18599 - 18604
(2021/08/09)
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- Iodine-Initiated Dioxygenation of Aryl Alkenes Using tert-Butylhydroperoxides and Water: A Route to Vicinal Diols and Bisperoxides
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An environment-friendly and efficient dioxygenation of aryl alkenes for the construction of vicinal diols has been developed in water with iodine as the catalyst and tert-butylhydroperoxides (TBHPs) as the oxidant. The protocol was efficient, sustainable, and operationally simple. Detailed mechanistic studies indicated that one of the hydroxyl groups is derived from water and the other one is derived from TBHP. Additionally, the bisperoxides could be obtained in good yields with iodine as the catalyst, Na2CO3 as the additive, and propylene carbonate as the solvent, instead.
- Gao, Xiaofang,Lin, Jiani,Zhang, Li,Lou, Xinyao,Guo, Guanghui,Peng, Na,Xu, Huan,Liu, Yi
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p. 15469 - 15480
(2021/11/16)
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- Lewis Base Catalyzed Dioxygenation of Olefins with Hypervalent Iodine Reagents
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1,2-Diols are extremely useful building blocks in organic synthesis. Hypervalent iodine reagents are useful for the vicinal dihydroxylation of olefins to give 1,2-diols under metal-free conditions, but strongly acidic promoters are often required. Herein, we report a catalytic vicinal dioxygenation of olefins with hypervalent iodine reagents using Lewis bases as catalysts. The conditions are mild and compatible with various functional groups.
- Pan, Liangkun,Ke, Zhihai,Yeung, Ying-Yeung
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supporting information
p. 8174 - 8178
(2021/10/25)
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- Synthesis and biological evaluation of triazolyl-substituted benzyloxyacetohydroxamic acids as LpxC inhibitors
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The bacterial deacetylase LpxC is a promising target for the development of antibiotics selectively combating Gram-negative bacteria. To improve the biological activity of the reported benzyloxyacetohydroxamic acid 9 ((S)-N-hydroxy-2-{2-hydroxy-1-[4-(phenylethynyl)phenyl]ethoxy}acetamide), its hydroxy group was replaced by a triazole ring. Therefore, in divergent syntheses, triazole derivatives exhibiting rigid and flexible lipophilic side chains, different configurations at their stereocenter, and various substitution patterns at the triazole ring were synthesized, tested for antibacterial and LpxC inhibitory activity, and structure-activity relationships were deduced based on docking and binding energy calculations.
- Hoff, Katharina,Mielniczuk, Sebastian,Agoglitta, Oriana,Iorio, Maria Teresa,Caldara, Manlio,Bülbül, Emre F.,Melesina, Jelena,Sippl, Wolfgang,Holl, Ralph
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supporting information
(2020/05/25)
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- Absolute stereochemical determination of 1,2-diols via complexation with dinaphthyl borinic acid
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Rapid derivatization of chiral 1,2-diols with dinaphthyl borinic acid (DBA) leads to a cyclic boronate, enabling the absolute stereochemical prediction via exciton-coupled circular dichroic (ECCD) of the naphthyl groups. Aryl- and alkyl-substituted 1,2-diols derivatized with DBA yield a predictable ECCD, which is also in agreement with theoretical predictions derived from computationally minimized structures.
- Torabi Kohlbouni, Saeedeh,Sarkar, Aritra,Zhang, Jun,Li, Xiaoyong,Borhan, Babak
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supporting information
p. 817 - 823
(2020/03/26)
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- Reprogramming Epoxide Hydrolase to Improve Enantioconvergence in Hydrolysis of Styrene Oxide Scaffolds
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Enantioconvergent hydrolysis by epoxide hydrolase is a promising method for the synthesis of important vicinal diols. However, the poor regioselectivity of the naturally occurring enzymes results in low enantioconvergence in the enzymatic hydrolysis of styrene oxides. Herein, modulated residue No. 263 was redesigned based on structural information and a smart variant library was constructed by site-directed modification using an “optimized amino acid alphabet” to improve the regioselectivity of epoxide hydrolase from Vigna radiata (VrEH2). The regioselectivity coefficient (r) of variant M263Q for the R-isomer of meta-substituted styrene oxides was improved 40–63-fold, and variant M263V also exhibited higher regioselectivity towards the R-isomer of para-substituted styrene oxides compared with the wild type, which resulted in improved enantioconvergence in hydrolysis of styrene oxide scaffolds. Structural insight showed the crucial role of residue No. 263 in modulating the substrate binding conformation by altering the binding surroundings. Furthermore, increased differences in the attacking distance between nucleophilic residue Asp101 and the two carbon atoms of the epoxide ring provided evidence for improved regioselectivity. Several high-value vicinal diols were readily synthesized (>88% yield, 90%–98% ee) by enantioconvergent hydrolysis using the reprogrammed variants. These findings provide a successful strategy for enhancing the enantioconvergence of native epoxide hydrolases through key single-site mutation and more powerful enzyme tools for the enantioconvergent hydrolysis of styrene oxide scaffolds into single (R)-enantiomers of chiral vicinal diols. (Figure presented.).
- Li, Fu-Long,Qiu, Yan-Yan,Zheng, Yu-Cong,Chen, Fei-Fei,Kong, Xu–Dong,Xu, Jian-He,Yu, Hui-Lei
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supporting information
p. 4699 - 4706
(2020/09/21)
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- Manipulating regioselectivity of an epoxide hydrolase for single enzymatic synthesis of (: R)-1,2-diols from racemic epoxides
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Both the activity and regioselectivity of Phaseolus vulgaris epoxide hydrolase were remarkably improved via reshaping two substrate tunnels based on rational design. The elegant one-step enantioconvergent hydrolysis of seven rac-epoxides was achieved by single mutants, allowing green and efficient access to valuable (R)-1,2 diols with high eep (90.1-98.3%) and yields.
- Hu, Die,Zong, Xun-Cheng,Xue, Feng,Li, Chuang,Hu, Bo-Chun,Wu, Min-Chen
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supporting information
p. 2799 - 2802
(2020/03/13)
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- One-step method for preparing racemic aryl vicinal diol in pure water
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The invention provides a one-step method for preparing racemic aryl vicinal diol in pure water. The method is characterized by comprising the following steps: dissolving metachloroperbenzoic acid intodeionized water, adding styrene compounds, heating in a water bath at 30 DEG C, stirring at a rotation speed of 200-300 revolutions per minute for reacting for 2-3 hours, extracting the reaction solution with ethyl acetate, drying, and removing the ethyl acetate, thereby obtaining the racemic aryl vicinal diol. According to the one-step method for preparing racemic aryl vicinal diol in pure waterdisclosed by the invention, the metachloroperbenzoic acid serves as an oxidizing agent in the deionized water, dihydroxylation of the styrene compounds is realized within 2-3 hours at high chemoselectivity and high yield, and the racemic aryl vicinal diol is prepared. The method avoids use of any organic solvent or heavy metal catalyst, is short in reaction time, mild in reaction condition, greenand environmental-friendly, simple in operation and readily available in catalyst, has potential application prospects, and solves the problems that the target product is low in yield, the catalyst is difficult to obtain, and the organic solvent is needed.
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Paragraph 0030-0032
(2019/03/08)
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- Asymmetric ring opening of racemic epoxides for enantioselective synthesis of (S)-β-amino alcohols by a cofactor self-sufficient cascade biocatalysis system
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A novel one-pot epoxide hydrolase/alcohol dehydrogenase/transaminase cascade process for the asymmetric ring opening of racemic epoxides to enantiopure β-amino alcohols is reported. The product (S)-β-amino alcohols were obtained in 97-99% ee and 79-99% conversion from readily available racemic epoxides.
- Zhang, Jian-Dong,Yang, Xiao-Xiao,Jia, Qiao,Zhao, Jian-Wei,Gao, Li-Li,Gao, When-Chao,Chang, Hong-Hong,Wei, Wen-Long,Xu, Jian-He
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- Exploiting Designed Oxidase-Peroxygenase Mutual Benefit System for Asymmetric Cascade Reactions
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A unique P450 monooxygenase-peroxygenase mutual benefit system was designed as the core element in the construction of a biocatalytic cascade reaction sequence leading from 3-phenyl propionic acid to (R)-phenyl glycol. In this system, P450 monooxygenase (P450-BM3) and P450 peroxygenase (OleTJE) not only function as catalysts for the crucial initial reactions, they also ensure an internal in situ H2O2 recycle mechanism that avoids its accumulation and thus prevents possible toxic effects. By directed evolution of P450-BM3 as the catalyst in the enantioselective epoxidation of the styrene-intermediate, formed from 3-phenyl propionic acid, and the epoxide hydrolase ANEH for final hydrolytic ring opening, (R)-phenyl glycol and 9 derivatives thereof were synthesized from the respective carboxylic acids in one-pot processes with high enantioselectivity.
- Yu, Da,Wang, Jian-Bo,Reetz, Manfred T.
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- Exploiting Designed Oxidase-Peroxygenase Mutual Benefit System for Asymmetric Cascade Reactions
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A unique P450 monooxygenase-peroxygenase mutual benefit system was designed as the core element in the construction of a biocatalytic cascade reaction sequence leading from 3-phenyl propionic acid to (R)-phenyl glycol. In this system, P450 monooxygenase (P450-BM3) and P450 peroxygenase (OleTJE) not only function as catalysts for the crucial initial reactions, they also ensure an internal in situ H2O2 recycle mechanism that avoids its accumulation and thus prevents possible toxic effects. By directed evolution of P450-BM3 as the catalyst in the enantioselective epoxidation of the styrene-intermediate, formed from 3-phenyl propionic acid, and the epoxide hydrolase ANEH for final hydrolytic ring opening, (R)-phenyl glycol and 9 derivatives thereof were synthesized from the respective carboxylic acids in one-pot processes with high enantioselectivity.
- Yu, Da,Wang, Jian-Bo,Reetz, Manfred T.
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p. 5655 - 5658
(2019/04/17)
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- Bifunctional organocatalysts for the conversion of CO2, epoxides and aryl amines to 3-aryl-2-oxazolidinones
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A route to synthesize 3-aryl-2-oxazolidinones is developed, which is achieved through a three component reaction between CO2, aryl amines, and epoxides with a binary organocatalytic system composed of organocatalysts and DBU (1,8-diazabicyclo[5.4.0]undec-7-ene). The method allows wide scopes of epoxide and aryl amine substrates with various functional groups under mild reaction conditions. The control experiments indicate that a cyclic carbonate is formed via cycloaddition of epoxides with CO2, which further reacts with the β-amino alcohol originating from epoxides and aryl amines, resulting in the formation of 3-aryl-2-oxazolidinones finally.
- Xie, Ya-Fei,Guo, Cheng,Shi, Lei,Peng, Bang-Hua,Liu, Ning
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supporting information
p. 3497 - 3506
(2019/04/14)
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- Cis -Oxoruthenium complexes supported by chiral tetradentate amine (N4) ligands for hydrocarbon oxidations
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We report the first examples of ruthenium complexes cis-[(N4)RuIIICl2]+ and cis-[(N4)RuII(OH2)2]2+ supported by chiral tetradentate amine ligands (N4), together with a high-valent cis-dioxo complex cis-[(N4)RuVI(O)2]2+ supported by the chiral N4 ligand mcp (mcp = N,N′-dimethyl-N,N′-bis(pyridin-2-ylmethyl)cyclohexane-1,2-diamine). The X-ray crystal structures of cis-[(mcp)RuIIICl2](ClO4) (1a), cis-[(Me2mcp)RuIIICl2]ClO4 (2a) and cis-[(pdp)RuIIICl2](ClO4) (3a) (Me2mcp = N,N′-dimethyl-N,N′-bis((6-methylpyridin-2-yl)methyl)cyclohexane-1,2-diamine, pdp = 1,1′-bis(pyridin-2-ylmethyl)-2,2′-bipyrrolidine)) show that the ligands coordinate to the ruthenium centre in a cis-α configuration. In aqueous solutions, proton-coupled electron-transfer redox couples were observed for cis-[(mcp)RuIII(O2CCF3)2]ClO4 (1b) and cis-[(pdp)RuIII(O3SCF3)2]CF3SO3 (3c′). Electrochemical analyses showed that the chemically/electrochemically generated cis-[(mcp)RuVI(O)2]2+ and cis-[(pdp)RuVI(O)2]2+ complexes are strong oxidants with E° = 1.11-1.13 V vs. SCE (at pH 1) and strong H-atom abstractors with DO-H = 90.1-90.8 kcal mol-1. The reaction of 1b or its (R,R)-mcp counterpart with excess (NH4)2[CeIV(NO3)6] (CAN) in aqueous medium afforded cis-[(mcp)RuVI(O)2](ClO4)2 (1e) or cis-[((R,R)-mcp)RuVI(O)2](ClO4)2 (1e?), respectively, a strong oxidant with E(RuVI/V) = 0.78 V (vs. Ag/AgNO3) in acetonitrile solution. Complex 1e oxidized various hydrocarbons, including cyclohexane, in acetonitrile at room temperature, affording alcohols and/or ketones in up to 66% yield. Stoichiometric oxidations of alkenes by 1e or 1e? in tBuOH/H2O (5:1 v/v) afforded diols and aldehydes in combined yields of up to 98%, with moderate enantioselectivity obtained for the reaction using 1e?. The cis-[(pdp)RuII(OH2)2]2+ (3c)-catalysed oxidation of saturated C-H bonds, including those of ethane and propane, with CAN as terminal oxidant was also demonstrated.
- Tse, Chun-Wai,Liu, Yungen,Wai-Shan Chow, Toby,Ma, Chaoqun,Yip, Wing-Ping,Chang, Xiao-Yong,Low, Kam-Hung,Huang, Jie-Sheng,Che, Chi-Ming
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p. 2803 - 2816
(2018/03/21)
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- Kinetic Resolution of 1,2-Diols via NHC-Catalyzed Site-Selective Esterification
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A kinetic resolution of 1,2-diols bearing both a secondary and a primary alcohol motif through an N-heterocyclic carbene-catalyzed oxidative acylation reaction has been developed. A site- and enantioselective esterification reaction is involved for this process. Both the monoacylated diols obtained and the remaining enantioenriched 1,2-diols are versatile building blocks for the preparation of functional molecules with proven biological activities.
- Liu, Bin,Yan, Jiekuan,Huang, Ruoyan,Wang, Weihong,Jin, Zhichao,Zanoni, Giuseppe,Zheng, Pengcheng,Yang, Song,Chi, Yonggui Robin
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supporting information
p. 3447 - 3450
(2018/06/26)
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- CATHEPSIN K INHIBITOR AND APPLICATION THEREOF
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The invention relates to capthepsin K inhibitors and uses thereof, specifically relates to a class of compounds having the formula (I) which are used for treating or preventing cathepsin dependent diseases or conditions, specifically, wherein the cathepsin is capthepsin K. The compounds and compositions thereof can be used as bone resorption inhibitors for the treatment of associated diseases.
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Paragraph 0254
(2018/07/29)
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- A Highly Regioselective Palladium-Catalyzed O,S Rearrangement of Cyclic Thiocarbonates
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This work describes an operationally simple catalytic synthesis of cyclic S-thiocarbonates with predictable regioselectivity in good yields. The reaction utilizes substrates derived from ubiquitous 1,2-diols in an atom economical intramolecular rearrangement, catalysed by an inexpensive and simple catalyst–ligand system. A crystal structure is presented that clearly confirms the regioselectivity of the reaction.
- Mahy, William,Cabezas-Hayes, Sinéad,Kociok-K?hn, Gabriele,Frost, Christopher G.
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supporting information
p. 6441 - 6444
(2017/11/13)
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- Visible light-promoted dihydroxylation of styrenes with water and dioxygen
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An efficient visible light promoted metal-free dihydroxylation of styrenes with water and dioxygen has been developed for the construction of vicinal alcohols. The protocol was operationally simple with a broad substrate scope. The mechanistic studies demonstrated that one of the hydroxyl groups came from water and the other one came from molecular oxygen. Additionally, the β-alkyoxy alcohols could also be obtained using a similar strategy.
- Yang, Bo,Lu, Zhan
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supporting information
p. 12634 - 12637
(2017/12/02)
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- Production Of Enantiopure alpha-Hydroxy Carboxylic Acids From Alkenes By Cascade Biocatalysis
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The invention provides compositions comprising an alkene epoxidase and a selective epoxide hydrolase, such as a recombinant microorganism comprising a first heterologous nucleic acid encoding an alkene epoxidase and a second heterologous nucleic acid encoding a selective epoxide hydrolase. Exemplary alkene epoxidases include StyAB, while exemplary selective epoxide hydrolases include epoxide hydrolases from Sphingomonas, Solanum tuberosum, or Aspergillus. The invention also provides non-toxic methods of making enantiomerically pure vicinal diols or enantiomerically pure alpha-hydroxy carboxylic acids using these compositions and microorganisms.
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Paragraph 0071-0073
(2016/05/02)
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- Enantioselective Vicinal Diacetoxylation of Alkenes under Chiral Iodine(III) Catalysis
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A procedure for the intermolecular enantioselective dioxygenation of alkenes under iodine(III) catalysis has been developed. This protocol employs Selectfluor as the terminal oxidant together with a defined C 2-symmetric aryl iodide as the organocatalyst. This enantioselective reaction proceeds under mild conditions and converts a series of terminal and internal styrenes into the corresponding vicinal diacetoxylation products with up to 96% ee.
- W?ste, Thorsten H.,Mu?iz, Kilian
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p. 816 - 827
(2016/03/15)
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- Structurally Defined Molecular Hypervalent Iodine Catalysts for Intermolecular Enantioselective Reactions
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Molecular structures of the most prominent chiral non-racemic hypervalent iodine(III) reagents to date have been elucidated for the first time. The formation of a chirally induced supramolecular scaffold based on a selective hydrogen-bonding arrangement provides an explanation for the consistently high asymmetric induction with these reagents. As an exploratory example, their scope as chiral catalysts was extended to the enantioselective dioxygenation of alkenes. A series of terminal styrenes are converted into the corresponding vicinal diacetoxylation products under mild conditions and provide the proof of principle for a truly intermolecular asymmetric alkene oxidation under iodine(I/III) catalysis.
- Haubenreisser, Stefan,W?ste, Thorsten H.,Martnez, Claudio,Ishihara, Kazuaki,Muiz, Kilian
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p. 413 - 417
(2016/01/25)
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- Highly Enantioselective Iron-Catalyzed cis-Dihydroxylation of Alkenes with Hydrogen Peroxide Oxidant via an FeIII-OOH Reactive Intermediate
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The development of environmentally benign catalysts for highly enantioselective asymmetric cis-dihydroxylation (AD) of alkenes with broad substrate scope remains a challenge. By employing [FeII(L)(OTf)2] (L=N,N′-dimethyl-N,N′-bis(2-methyl-8-quinolyl)-cyclohexane-1,2-diamine) as a catalyst, cis-diols in up to 99.8 % ee with 85 % isolated yield have been achieved in AD of alkenes with H2O2as an oxidant and alkenes in a limiting amount. This “[FeII(L)(OTf)2]+H2O2” method is applicable to both (E)-alkenes and terminal alkenes (24 examples >80 % ee, up to 1 g scale). Mechanistic studies, including18O-labeling, UV/Vis, EPR, ESI-MS analyses, and DFT calculations lend evidence for the involvement of chiral FeIII-OOH active species in enantioselective formation of the two C?O bonds.
- Zang, Chao,Liu, Yungen,Xu, Zhen-Jiang,Tse, Chun-Wai,Guan, Xiangguo,Wei, Jinhu,Huang, Jie-Sheng,Che, Chi-Ming
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supporting information
p. 10253 - 10257
(2016/08/24)
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- Ru-MACHO-Catalyzed Highly Chemoselective Hydrogenation of α-Keto Esters to 1,2-Diols or α-Hydroxy Esters
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A ruthenium pincer catalyst has been shown to be highly effective for the hydrogenation of a wide range of α-keto esters, affording either diols or hydroxy esters depending on the choice of reaction conditions. Strong base, high temperature, and pressure favor the formation of diols whilst the opposite is true for the hydroxy esters.
- Gao, Shaochan,Tang, Weijun,Zhang, Minghui,Wang, Chao,Xiao, Jianliang
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supporting information
p. 1748 - 1752
(2016/07/06)
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- COMPOSITIONS USEFUL FOR TREATING DISORDERS RELATED TO KIT
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Compounds and compositions useful for treating disorders related to Kit are described herein.
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- Cis-Dioxomolybdenum(VI) complexes with unsymmetric linear tetradentate ligands: Syntheses, structures and bromoperoxidase activities
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Reactions of [MoO2(acetylacetonate)2], 2-((2-(2-hydroxyethylamino)ethylamino)methyl)-4-R-phenols (H2Ln, n = 1-5 for R = H, Me, OMe, Cl and Br, respectively) and KOH in 1:1:2 mole ratio in methanol afford a series of complexes having the general formula cis-[MoO2(Ln)] (1, 2, 3, 4, 5) in 81-86% yields. The complexes have been characterized using elemental analysis, spectroscopy (infrared, UV-visible, and 1H NMR, 13C NMR and 13C-DEPT NMR) and electrochemical measurements. The molecular structures of 1, 2, 3, 4 have been determined using single-crystal X-ray crystallography. In each of 1, 2, 3, 4, the ONNO-donor 6,5,5-membered fused chelate rings forming (Ln)2- and the two mutually cis oxo groups assemble a distorted octahedral N2O4 coordination sphere around the metal centre. In the crystal lattice, each of 1, 2, 3, 4 forms a one-dimensional infinite chain structure via intermolecular N-H...O hydrogen bonding interactions. In cyclic voltammograms, the diamagnetic complexes display an irreversible metal-centred reduction in the potential range -0.73 to -0.88 V (vs Ag/AgCl). The physicochemical data are consistent with a very similar gross molecular structure for all of 1, 2, 3, 4, 5. All the complexes exhibit decent bromoperoxidase activities and are also able to effectively catalyse benzoin and methyl(phenyl)sulfide oxidation reactions.
- Kurapati, Sathish Kumar,Pal, Samudranil
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p. 116 - 124
(2016/02/18)
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- Oxidative cleavage of olefins by in situ-generated catalytic 3,4,5,6-tetramethyl-2-iodoxybenzoic acid/oxone
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Oxidative cleavage of a variety of olefins to the corresponding ketones/carboxylic acids is shown to occur in a facile manner with 3,4,5,6-tetramethyl-2-iodobenzoic acid (TetMe-IA)/oxone. The simple methodology involves mere stirring of the olefin and catalytic amount (10 mol %) of TetMe-IA and oxone in acetonitrile-water mixture (1:1, v/v) at rt. The reaction mechanism involves initial dihydroxylation of the olefin with oxone, oxidative cleavage by the in situ-generated 3,4,5,6-tetramethyl-2-iodoxybenzoic acid (TetMe-IBX), and oxidation of the aldehyde functionality to the corresponding acid with oxone. Differences in the reactivities of electron-rich and electron-poor double bonds have been exploited to demonstrate chemoselective oxidative cleavage in substrates containing two double bonds.
- Moorthy, Jarugu Narasimha,Parida, Keshaba Nanda
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p. 11431 - 11439
(2015/02/05)
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- Highly Efficient Synthesis of Optically Pure (S)-1-phenyl-1,2-ethanediol by a Self-Sufficient Whole Cell Biocatalyst
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Terminal vicinal diols are important chiral building blocks and intermediates in organic synthesis. Reduction of α-hydroxy ketones provides a straightforward approach to access these important compounds. In this study, it has been found that asymmetric reduction of a series of α-hydroxy aromatic ketones and 1-hydroxy-2-pentanone, catalyzed by Candida magnolia carbonyl reductase (CMCR) with glucose dehydrogenase (GDH) from Bacillus subtilis for cofactor regeneration, afforded 1-aryl-1,2-ethanediols and pentane-1,2-diol, respectively, in up to 99 % ee. In order to evaluate the efficiency of the bioreduction, lyophilized recombinant Escherichia coli whole cells coexpressing CMCR and GDH genes were used as the biocatalyst and α-hydroxy acetophenone as the model substrate, and the reaction conditions, such as pH, cosolvent, the amount of biocatalyst and the presences of a cofactor (i.e., NADP+), were optimized. Under the optimized conditions (pH6, 16h), the bioreduction proceeded smoothly at 1.0 m substrate concentration without the external addition of cofactor, and the product (S)-1-phenyl-1,2-ethanediol was isolated with 90 % yield and 99 % ee. This offers a practical biocatalytic method for the preparation of these important vicinal diols. Self-sufficient catalysis! Lyophilized recombinant Escherichia coli coexpressing Candida magnolia carbonyl reductase (CMCR) and glucose dehydrogenase (GDH) genes served as an effective self-sufficient biocatalyst for the reduction of α-hydroxy acetophenones at high substrate concentrations. The products were isolated with high yield and excellent optical purity, offering a practical biocatalytic method for the preparation of vicinal diols.
- Chen, Xi,Mei, Ting,Cui, Yunfeng,Chen, Qijia,Liu, Xiangtao,Feng, Jinhui,Wu, Qiaqing,Zhu, Dunming
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p. 483 - 488
(2015/10/06)
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- Synthesis, biological evaluation and molecular docking studies of benzyloxyacetohydroxamic acids as LpxC inhibitors
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The inhibition of the UDP-3-O-[(R)-3-hydroxymyristoyl]-N-acetylglucosamine deacetylase (LpxC) represents a promising strategy to combat infections caused by multidrug-resistant Gram-negative bacteria In order to elucidate the functional groups being impor
- Szermerski, Marina,Melesina, Jelena,Wichapong, Kanin,L?ppenberg, Marius,Jose, Joachim,Sippl, Wolfgang,Holl, Ralph
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p. 1016 - 1028
(2014/02/14)
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- Enantioselective trans-dihydroxylation of aryl olefins by cascade biocatalysis with recombinant escherichia coli coexpressing monooxygenase and epoxide hydrolase
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Cascade biocatalysis via intracellular epoxidation and hydrolysis was developed as a green and efficient method for enantioselective dihydroxylation of aryl olefins to prepare chiral vicinal diols in high ee and high yield. Escherichia coli (SSP1) coexpressing styrene monooxygenase (SMO) and epoxide hydrolase SpEH was developed as a simple and efficient biocatalyst for S-enantioselective dihydroxylation of terminal aryl olefins 1a-15a to give (S)-vicinal diols 1c-15c in high ee (97.5-98.6% for 10 diols; 92.2-93.9% for 3 diols) and high yield (91-99% for 6 diols; 86-88% for 2 diols; 67% for 3 diols). Combining SMO and epoxide hydrolase StEH showing complementary regioselectivity to SpEH as a biocatalyst for the cascade biocatalysis gave rise to R-enantioselective dihydroxylation of aryl olefins, being the first example of this kind of reversing the overall enantioselectivity of cascade biocatalysis. E. coli (SST1) coexpressing SMO and StEH was also engineered as a green and efficient biocatalyst for R-dihydroxylation of terminal aryl olefins 1a-15a to give (R)-vicinal diols 1c-15c in high ee (94.2-98.2% for 7 diols; 84.2-89.9% for 6 diols) and high yield (90-99% for 6 diols; 85-89% for 5 diols; 65% for 1 diol). E. coli (SSP1) and E. coli (SST1) catalyzed the trans-dihydroxylation of trans-aryl olefin 16a and cis-aryl olefin 17a with excellent and complementary stereoselectivity, giving each of the four stereoisomers of 1-phenyl-1,2- propanediol 16c in high ee and de, respectively. Both strains catalyzed the trans-dihydroxylation of aryl cyclic olefins 18a and 19a to afford the same trans-cyclic diols (1R,2R)-18c and (1R,2R)-19c, respectively, in excellent ee and de. This type of cascade biocatalysis provides a tool that is complementary to Sharpless dihydroxylation, accepting cis-alkene and offering enantioselective trans-dihydroxylation.
- Wu, Shuke,Chen, Yongzheng,Xu, Yi,Li, Aitao,Xu, Qisong,Glieder, Anton,Li, Zhi
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p. 409 - 420
(2014/03/21)
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- Enhanced brightness emission-tuned nanoparticles from heterodifunctional polyfluorene building blocks
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Three-coordinate complexes (bromo)[4-(2,2-dimethyl-1,3-dioxolan-4-yl)- phenyl](tri-tert-butyl-phosphine)palladium (1) and (bromo){4-[(tetrahydro-2H- pyran-2-yloxy)methyl]phenyl}(tri-tert-butyl-phosphine)palladium (2) were used to initiate Suzuki-Miyaura chain growth polymerization of 7′-bromo-9′, 9′-dioctyl-fluoren-2′-yl-4,4,5,5-tetramethyl-[1,3,2]dioxaborolane (3). The polymerization was optionally terminated by end-capping with red-emitting N-(2-ethylhexyl)-1,6-bis(4-tert-octylphenoxy)-9-(4,4,5,5- tetramethyl-[1,3,2]dioxaborolan-2-yl)-perylene-3,4-dicarboximide. Heterodisubstituted polyfluorenes of adjustable molecular weights between 5 × 103 and 1.0 × 104 g mol-1 and narrow molecular weight distribution (Mw/Mn n = 2 × 103 g mol-1) to the reactive end groups yielded amphiphilic block copolymer, which afforded stable nanoparticles with diameters in the range of 25-50 nm when dispersed in water. These particles exhibited a bright fluorescence emission with quantum yields as high as Φ = 84%, which could optionally be tuned to longer wavelengths by energy transfer to the perylene monoimide dye. The heterodifunctional nature of these polyfluorenes is crucial for a bright and enduring fluorescence brightness as revealed by comparison to nanoparticles containing physically mixed dye. Further addition of terrylene diimide dye to the nanoparticles of perylene-end-capped polyfluorene block copolymers allows for an energy cascade resulting in emission exclusively in the deep red and near-infrared regime.
- Fischer, Christoph S.,Baier, Moritz C.,Mecking, Stefan
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supporting information
p. 1148 - 1154
(2013/04/10)
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- Enantioselective synthesis of terminal 1,2-diols from acyl chlorides
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Optically active terminal 1,2-diols were prepared with high enantiopurity via the TMS-quinidine-catalyzed enantioselective cyclization of acyl chlorides and oxaziridine, followed by reductive ring-opening of the cycloadducts.
- Shao, Panlin,Shen, Litao,Ye, Song
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p. 2688 - 2692
(2013/01/15)
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- Metal-free dihydroxylation of alkenes using cyclobutane malonoyl peroxide
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Cyclobutane malonoyl peroxide (7), prepared in a single step from the commercially available diacid 6, is an effective reagent for the dihydroxylation of alkenes. Reaction of a chloroform solution of 7 with an alkene in the presence of 1 equiv of water at 40 °C followed by alkaline hydrolysis leads to the corresponding diol (30-84%). With 1,2-disubstituted alkenes, the reaction proceeds with syn-selectivity (3:1 → 50:1). A mechanism consistent with experimental findings is proposed, which is supported by deuterium and oxygen labeling studies and explains the stereoselectivity observed. Alternative reaction pathways that are dependent on the structure of the starting alkene are also described leading to the synthesis of allylic alcohols and γ-lactones.
- Jones, Kevin M.,Tomkinson, Nicholas C. O.
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experimental part
p. 921 - 928
(2012/02/16)
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- SUBSTITUTED BENZOAZEPINES AS TOLL-LIKE RECEPTOR MODULATORS
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Provided are compositions and methods useful for modulation of signaling through the Toll-like receptors TLR7 and/or TLR8. The compositions and methods have use in treating or preventing disease, including cancer, autoimmune disease, infectious disease, inflammatory disorder, graft rejection, and graft-verses-host disease.
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Page/Page column 89; 90
(2011/04/13)
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- One-pot synthesis of enantiomerically pure 1, 2-diols: Asymmetric reduction of aromatic α-oxoaldehydes catalysed by Candida parapsilosis ATCC 7330
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A facile and simple one-pot method was developed to produce a series of optically active (S)-1-phenyl-1,2-ethanediols with good yields (up to 70%) and high enantiomeric excess (>99%) via asymmetric reduction of various substituted aromatic α-oxoaldehydes using Candida parapsilosis ATCC 7330.
- Mahajabeen, Pula,Chadha, Anju
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p. 2156 - 2160
(2012/05/04)
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- Alkene syn dihydroxylation with malonoyl peroxides
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Cyclopropyl malonoyl peroxide (1), which can be prepared in a single step from the commercially available diacid, is an effective reagent for the dihydroxylation of alkenes. Reaction of 1 with an alkene in the presence of 1 equiv of water at 40 °C followed by alkaline hydrolysis leads to the corresponding diol (40-93%). With 1,2-disubstituted alkenes, the reaction proceeds with syn selectivity (3:1 to >50:1). A mechanism consistent with the experimental findings that is supported by oxygen-labeling studies is proposed.
- Griffith, James C.,Jones, Kevin M.,Picon, Sylvain,Rawling, Michael J.,Kariuki, Benson M.,Campbell, Matthew,Tomkinson, Nicholas C. O.
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supporting information; experimental part
p. 14409 - 14411
(2010/12/24)
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- Palladium-catalyzed direct oxidation of alkenes with molecular oxygen: General and practical methods for the preparation of 1, 2-diols, aldehydes, and ketones
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(Figure Presented) 1, 2-Diols, aldehydes, and ketones are important intermediates in chemical synthesis, and alkenes are possible precursors for 1, 2-diols, aldehydes, and ketones. Herein, novel and environmentally benign methods for palladium-catalyzed dihydroxylation and oxidative cleavage of olefins with oxygen as sole oxidant are presented. The cleavage reactions were performed with acid as additive in aqueous solution, whereas 1, 2-diols were formed in the presence of base. A broad substrate scope has been demonstrated allowing monosubstituted aromatic and aliphatic terminal alkenes, 1, 2-disubstituted, and 1, 1-disubstituted olefins. The cleavage reactions of dioxo-PdII complexes implicate 1, 2-diol might act as a key intermediate of olefin cleavage.
- Wang, Azhong,Jiang, Huanfeng
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supporting information; experimental part
p. 2321 - 2326
(2010/07/04)
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- INHIBITORS OF AKT ACTIVITY
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The instant invention provides for substituted fused naphthyridine derivatives that inhibit Akt activity. In particular, the compounds disclosed selectively inhibit one or two of the Akt isoforms. The invention also provides for compositions comprising such inhibitory compounds and methods of inhibiting Akt activity by administering the compound to a patient in need of treatment of cancer.
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Page/Page column 152-153
(2010/10/03)
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- CuI/l-proline-catalyzed selective one-step mono-acylation of styrenes and stilbenes
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Vicinal di-oxygenation of styrene-type olefins was achieved with cheaper, less toxic CuI in the presence of l-proline as ligand and NaIO4 as the oxidant. This approach provides a straightforward and efficient access to mono-acylated diols from both styrene and stilbene derivatives with good to excellent yields and diastereoselectivity.
- Prathima, P. Sai,Maheswari, C. Uma,Srinivas,Rao, M. Mohan
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supporting information; experimental part
p. 5771 - 5774
(2010/11/05)
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- PROGESTERONE RECEPTOR ANTAGONISTS
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The present invention relates to progesterone receptor antagonists of general formula I: in which R1 can be a hydrogen atom and R2 a hydroxyl group or R1 and R2 together can be an oxo group.
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Page/Page column 8
(2008/12/05)
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- A rapid 1,2-dihydroxylation of alkenes using a lipase and hydrogen peroxide under microwave conditions
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The combined advantages of using an enzyme immobilized lipase from Pseudomonas sp [PSLG6], hydrogen peroxide, ethyl acetate and microwave irradiation for the dihydroxylation of olefins are reported.
- Sarma, Kuladip,Borthakur, Naleen,Goswami, Amrit
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p. 6776 - 6778
(2008/02/13)
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- New mono-quarternized bis-Cinchona alkaloid ligands for asymmetric dihydroxylation of olefins in aqueous medium: Unprecedented high enantioselectivity and recyclability
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New mono-quaternized allyl bromide salts of bis-Cinchona alkaloid ligands, [(QD)2PHAL-Allyl]Br and [(QN)2PHAL-Allyl]Br, have been synthesized which can be converted into their highly water-soluble multihydroxylated derivatives under asymmetric dihydroxylation (AD) conditions and, thus, easily recovered by a simple extraction method after reaction and reused. These mono-quaternized ligands exhibited superior catalytic efficiency to their neutral counterparts such as (DHQD)2PHAL and (DHQ) 2PHAL for the AD reactions of mono- and disubstituted styrenes under Upjohn conditions. Merely 0.1 mol% of osmium was enough to complete the reactions of mono- and disubstituted styrenes and, moreover, these ligands showed the highest enantioselectivities (e.g., for styrene, 97% ee with [(QD)2PHAL-Allyl]Br) among those ever achieved under Upjohn conditions. Wiley-VCH Verlag GmbH & Co. KGaA.
- Choi, Doo Seung,Han, Sang Seop,Kwueon, Eun Kyung,Choi, Han Young,Hwang, Soon Ho,Park, Yil Sung,Song, Choong Eui
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p. 2560 - 2564
(2007/10/03)
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- COMPOUNDS WHICH POTENTIATE GLUTAMATE RECEPTOR AND USES THEREOF IN MEDICINE
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This invention relates to potentiation of the glutamate receptor by novel compounds of formula (I): The invention also relates to the use of the derivatives in treating diseases and conditions mediated by potentiation of the glutamate receptor, compositio
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Page/Page column 41
(2008/06/13)
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- NaIO4/LiBr-mediated diastereoselective dihydroxylation of olefins: A catalytic approach to the prevost-woodward reaction
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(Chemical Equation Presented) LiBr catalyzes efficiently the dihydroxylation of alkenes to afford syn and anti diols with excellent diastereoselectivity depending upon the use of NaIO4 (30 mol %) or PhI(OAc)2 (1 equiv), respectively, as the oxidants. The oxidation of non-benzylic halides has been achieved for the first time to afford the corresponding diols in excellent yields.
- Emmanuvel, Lourdusamy,Ali Shaikh, Tanveer Mahammad,Sudalai, Arumugam
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p. 5071 - 5074
(2007/10/03)
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- Enantioselective hydrolysis of various substituted styrene oxides with Aspergillus Niger CGMCC 0496
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Enantioselective biohydrolysis of various substituted styrene oxides using whole fungus cells of Aspergillus niger CGMCC 0496 are described. The results show not only para- but also some ortho- substituted styrene oxides can achieve high enantioselectivity during the hydrolysis.
- Jin, Hao,Li, Zu-Yi,Dong, Xiao-Wei
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p. 408 - 414
(2007/10/03)
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- Chemoenzymatic synthesis of enantiomerically pure 1,2-diols employing immobilized lipase in the ionic liquid [bmim]PF6
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Significantly enhanced enantioselectivity in the enzymatic kinetic resolution of 1,2-diols employing immobilized lipase from Pseudomonas cepacia (PS-C, 'Amano') results from the use of the ionic liquid [bmim]PF6 as reaction medium.
- Kamal, Ahmed,Chouhan, Gagan
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p. 8801 - 8805
(2007/10/03)
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- Enantioselective reduction of α-keto esters to 1,2-diols using the NaBH4/Me3SiCl system catalyzed by polymer-supported chiral sulfonamide
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In the presence of 25mol% of a polymer-supported chiral sulfonamide, a variety of α-keto esters can be reduced into the corresponding 1,2-diols in good yields and high enantioselectivities using the NaBH4/Me 3SiCl reducing system.
- Wang, Guang-Yin,Hu, Jian-Bing,Zhao, Gang
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p. 807 - 810
(2007/10/03)
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- Chemoenzymatic synthesis of enantiomerically pure terminal 1,2-diols
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A new practical method for the enzymatic synthesis of 1,2-diols has been developed by employing a lipase catalyzed one-pot transesterification protocol. A series of substituted α-acetoxyphenylethanones 3a-g have been reduced to the corresponding alcohols under mild conditions employing sodium borohydride and moist neutral alumina, and further subjected for lipase catalyzed irreversible transesterification in the same pot to give mono- and diacetate diols (R)-4 and (S)-5, which on hydrolysis afforded terminal 1,2-diols, (R)- and (S)-6 in high enantiomeric excess.
- Kamal, Ahmed,Sandbhor, Mahendra,Ahmed, Kaleem,Adil,Shaik, Ahmad Ali
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p. 3861 - 3866
(2007/10/03)
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- An effective and useful synthesis of enantiomerically enriched arylglycinols
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A two-step synthesis of racemic arylglycinols, together with a simple and straightforward methodology for their resolution, is described. This method constitutes a practical means of preparing racemic and optically pure electron-rich or electron-poor subs
- Bandini, Marco,Cozzi, Pier Giorgio,Gazzano, Massimo,Umani-Ronchi, Achille
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p. 1937 - 1942
(2007/10/03)
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