- Asymmetric Synthesis of Pyridylethanols and Amino Alcohols by Enantioselective Reduction with Lithium Borohydride Modified with N,N'-Dibenzoylcystine
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Optically active 1-pyridylethanols and β- and γ-amino alcohols are obtained in high enantiomeric excess from the enantioselective reduction of acetylpyridines and amino ketones using lithium borohydride, N,N'-dibenzoylcystine, and ethanol.
- Soai, Kenso,Niwa, Seiji,Kobayashi, Takashi
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- Synthesis and application in enantioselective hydrogenation of new free and chromium complexed aminophosphine-phosphinite ligands
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A straightforward synthesis of new free and Cr(CO)3 complexed AMPP ligands (4-7) is described starting from (S)-indoline-2-carboxylic acid. The ligands were applied successfully in the asymmetric hydrogenation of α-functionalized ketones i.e. a ketolactone 8, a ketoamide 9 and an aminoketone 10 leading to the corresponding optically active alcohols in 99, 97, and 99% ee respectively.
- Pasquier, Corinne,Naili, Said,Pelinski, Lydie,Brocard, Jacques,Mortreux, Andre,Agbossou, Francine
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- An iron variant of the Noyori hydrogenation catalyst for the asymmetric transfer hydrogenation of ketones
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We report the design of a new iron catalyst for the asymmetric transfer hydrogenation of ketones. This type of iron catalyst combines the structural characteristics of the Noyori hydrogenation catalyst (an axially chiral 2,2′-bis(phosphino)-1,1′-binaphthyl fragment and the metal-ligand bifunctional motif) and an ene(amido) group that can activate the iron center. After activation by 8 equivalents of potassiumtert-butoxide, (SA,RP,SS)-7aand (SA,RP,SS)-7bare active but nonenantioselective catalysts for the transfer hydrogenation of acetophenone and α,β-unsaturated aldehydes at room temperature in isopropanol. A maximum turnover number of 14480 was observed for (SA,RP,SS)-7ain the reduction of acetophenone. The right combination of the stereochemistry of the axially chiral 2,2′-bis(phosphino)-1,1′-binaphthyl group and the carbon-centered chiral amine-imine moiety in (SA,RP,RR)-7b′afforded an enantioselective catalyst for the preparation of chiral alcohols with moderate to good yields and a broad functional group tolerance.
- Huo, Shangfei,Wang, Qingwei,Zuo, Weiwei
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supporting information
p. 7959 - 7967
(2020/06/26)
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- waylen apperception HIV reverse transcriptase inhibitors in accordance with the law of the process for the asymmetric synthesis of one-pot synthesis (by machine translation)
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The invention relates to a novel one pot method asymmetric synthesis process of a (S)-6-chlorine-4-cylopropyl ethylnen-4-trifluoromethyl-1,4-dihydro-2H-1,3-benzoxazine-2-ketone (Efavirenz) compound, the compound can be used as an reverse transcriptase inhibitor for human immunodeficiency virus (HIV). The invention also relates to a novel aminoalcohol ligand used for the process.
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Paragraph 0179; 0180; 0181
(2016/10/07)
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- Discovery of pyrroloaminopyrazoles as novel PAK inhibitors
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The P21-activated kinases (PAK) are emerging antitumor therapeutic targets. In this paper, we describe the discovery of potent PAK inhibitors guided by structure-based drug design. In addition, the efflux of the pyrrolopyrazole series was effectively reduced by applying multiple medicinal chemistry strategies, leading to a series of PAK inhibitors that are orally active in inhibiting tumor growth in vivo.
- Guo, Chuangxing,McAlpine, Indrawan,Zhang, Junhu,Knighton, Daniel D.,Kephart, Susan,Johnson, M. Catherine,Li, Haitao,Bouzida, Djamal,Yang, Anle,Dong, Liming,Marakovits, Joseph,Tikhe, Jayashree,Richardson, Paul,Guo, Lisa C.,Kania, Robert,Edwards, Martin P.,Kraynov, Eugenia,Christensen, James,Piraino, Joseph,Lee, Joseph,Dagostino, Eleanor,Del-Carmen, Christine,Deng, Ya-Li,Smeal, Tod,Murray, Brion W.
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experimental part
p. 4728 - 4739
(2012/07/28)
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- Enantioselective reduction of α-substituted ketones mediated by the boronate ester TarB-NO2
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A facile and mild reduction procedure is reported for the preparation of chiral secondary alcohols prepared from α-substituted ketones using sodium borohydride and the chiral boronate ester (l)-TarB-NO2. Direct reduction of substituted ketones bearing Lewis basic heteroatoms generally provided secondary alcohols of only modest enantiomeric excess likely due to either competition between the target carbonyl and the functionalized sidechains at the Lewis acidic boron atom in TarB-NO2 or the added steric bulk of the α-sidechain. As an alternative method, these substrates were synthesized using TarB-NO2 via a two-step procedure involving the reduction of an α-halo ketone to a chiral terminal epoxide, followed by regioselective/regiospecific epoxide opening by various nucleophiles. This procedure provides access to a variety of functionalized secondary alcohols including β-hydroxy ethers, thioethers, nitriles, and amines with enantiomeric excesses of 94% and yields up to 98%.
- Eagon, Scott,Ball-Jones, Nicholas,Haddenham, Dustin,Saavedra, Jaime,Delieto, Cassandra,Buckman, Matthew,Singaram, Bakthan
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supporting information; scheme or table
p. 6418 - 6421
(2010/12/30)
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- CARBONYLAMINO PYRROLOPYRAZOLES, POTENT KINASE INHIBITORS
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Carbonylamino Pyrrolopyrazole compounds of formula I, compositions including these compounds and methods of their use are provided. Preferred compounds of formula I have activity as protein kinase inhibitors, including as inhibitors of PAK4.
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Page/Page column 45
(2009/12/28)
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- Catalytic asymmetric borane reduction of prochiral ketones by using (S)-2-(anilinomethyl)pyrrolidine
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Catalytic asymmetric borane reduction of prochiral ketones was examined in the presence of (S)-2-(anilinornethyl)pyrrolidine. Chiral secondary alcohols were obtained with moderate to high enantiomeric excesses (up to 96% ee).
- Hosoda, Naoya,Iogawa, Yoshihiro,Shimada, Yuichi,Asami, Masatoshi
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experimental part
p. 274 - 277
(2009/03/12)
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- Electroreductive generation of (S)-(+)-N,N-dimethyl-2-(hydroxymethyl)- pyrrolidinium mercury compound for enantioselective synthesis of 2-amino-1-alkyl/aryl ethanols
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(S)-(+)-N, N - Dimethyl-2-(hydroxymethyl)-pyrrolidinium (DMHP +)-mercury compound mediated enantioselective reduction of aminomethyl alkyl/aryl ketones in dimethylformamide-2-propanol (9:1) has been carried out using tetrabutylammonium tetrafluoroborate as a supporting electrolyte. The products viz. 2-amino-1-alkyl/aryl ethanols have been obtained in good yield (68-92%) with 35-91% optical purity and have been assigned (S)-configuration. The pinacol (racemic/meso) derivatives are also isolated as minor products (yield 5-20%) via dimerization of radical anion followed by protonation.
- Yadav, Ashok K.,Manju, Meera
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p. 2770 - 2772
(2008/04/18)
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- Highly enantioselective synthesis of β-amino alcohols
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N,N-Dialkyl-β-amino alcohols derived from α-amino acids can be rearranged enantiospecifically by using TFAA/Et3N/NaOH to give 1,2-amino alcohols with enantiomeric excess up to 99%.
- Metro, Thomas-Xavier,Appenzeller, Jerome,Pardo, Domingo Gomez,Cossy, Janine
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p. 3509 - 3512
(2007/10/03)
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- Chiral tricarbonyl(η6-arene)chromium complexed diphosphanes. Highly enantioselective rhodium-mediated hydrogenation of ketones
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Arenechromium complexed diastereomeric aminophosphine-phosphinite ligands derived from tetrahydroisoquinoline have been synthesised and examined as chiral auxiliaries in the hydrogenation of functionalised ketones. A cyclopentyl-substituted anti-stereoisomer is providing the highest enantioselectivities (up to >99% ee).
- Pasquier, Corinne,Pélinski, Lydie,Brocard, Jacques,Mortreux, André,Agbossou-Niedercorn, Francine
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p. 2809 - 2812
(2007/10/03)
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- AUXILIARY SRTUCTURE AND ASYMMETRIC INDUCTION IN THE "MUKAIYAMA-ALDOL" REACTIONS OF CHIRAL SILYL KETENE ACETALS
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A variety of chiral auxiliaries R*OH were prepared and tested for levels of asymmetric induction control in the "Mukaiyama-aldol" reaction of chiral silyl ketene acetals.Structural features required for high levels of control are discussed.
- Gennari, Cesare,Molinari, Francesco,Cozzi, PierGiorgio,Oliva, Ambrogio
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p. 5163 - 5166
(2007/10/02)
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