115016-95-0Relevant articles and documents
Chirality switching in the enantioseparation of 2-hydroxy-4-phenylbutyric acid: Role of solvents in selective crystallization of the diastereomeric salt
Hirose, Takuji,Kodama, Koichi,Shitara, Hiroaki,Yi, Meng
supporting information, (2020/03/04)
Chirality switching was induced by solvents in the enantioseparation of 2-hydroxy-4-phenylbutyric acid (HPBA) via diastereomeric salt formation with an enantiopure aminoalcohol. The (S)-salt was crystallized from butanol solutions and the (R)-salt was obt
Iridium/f-Amphox-Catalyzed Asymmetric Hydrogenation of Styrylglyoxylamides
Wang, Simin,Yu, Yuena,Wen, Jialin,Zhang, Xumu
supporting information, p. 2203 - 2207 (2018/09/29)
We report an iridium-catalyzed asymmetric hydrogenation reaction for the preparation of chiral homophenylalanine derivatives. Catalyzed by an iridium/f-amphox complex, the asymmetric hydrogenation of styrylglyoxylamides was conducted smoothly with turnover numbers of up to 10,000 and up to 98% ee. This method was successfully applied in a synthesis of a fragment of benazepril, a drug used for the treatment of high blood pressure.
Asymmetric hydrogenation method of alpha-ketone amide compound
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Paragraph 0185; 0189; 0190, (2018/10/04)
The invention belongs to the field of asymmetric catalysis, and discloses an asymmetric hydrogenation method of an alpha-ketone amide compound. The asymmetric hydrogenation method comprises the following steps that under the existence of a catalyst, alkali and a solvent, an alpha-ketone-beta-alkene amide compound is subjected to reduction in the hydrogen atmosphere, and an alpha-hydroxyl-beta alkene amide compound is obtained; and the catalyst is obtained through complexing of metal iridium salt and a chiral ligand, and the chiral ligand is selected from the following compounds: (the formulasare shown in the description). The asymmetric hydrogenation method is easy to operate, high in conversion rate and selectivity and low in cost, has the advantages of being high in atom economy and environmentally friendly, and has a very good industrialized application prospect.
Asymmetric synthesis of (S)-dihydrokavain from l-malic acid
Eskici, Mustafa,Karanfil, Abdullah,?zer, M. Sabih,Kabak, Yal??n,Durucasu, ?nci
, p. 2382 - 2390 (2018/10/20)
A practical and efficient asymmetric synthesis of (S)-dihydrokavain from known ethyl (S)-2-hydroxy-4-phenylbutanoate which is, in turn, readily available from l-malic acid as a cheap chiral pool material is described using regioselective ring-opening of the 1,2-cyclic sulfate with lithium-3,3,3-triethoxypropiolate and subsequent HgO/H2SO4-mediated lactonization as the key steps. Its opposite enantiomer (R)-dihydrokavain was also synthesized from d-malic acid using the same sequences of reactions for the purpose of optical purity determination.
Improving enantioselectivity of lipase from Candida rugosa by carrier-bound and carrier-free immobilization
Velasco-Lozano, Susana,López-Gallego, Fernando,Rocha-Martin, Javier,Guisán, José Manuel,Favela-Torres, Ernesto
, p. 32 - 39 (2016/06/01)
The enantioselectivity of carrier-bound and carrier-free immobilized lipase from Candida rugosa (CRL) was studied. CRL was immobilized in six agarose-based carriers functionalized with different reactive groups and in two different CRL cross-linked aggregates. Both, activity and enantioselectivity of all the immobilized lipase preparations were evaluated with different racemic esters under different reaction conditions (temperature, pH and solvent polarity). A strong effect of reaction media and immobilization protocol on enzyme activity and selectivity was found. Enzyme immobilization and reaction engineering allowed us obtaining the best immobilization protocol and reaction conditions to achieve high activity and enantioselectivty of CRL as heterogeneous catalyst. CRL immobilized on an agarose-based carrier activated with primary amino groups preferentially hydrolyzed (S)-phenylethyl acetate with E > 200 under pH 7, 4 °C and 30% of acetonitrile. On the other hand, CRL aggregated and cross-linked through their carboxylic groups preferentially hydrolyzed the (S)-isomer of ethyl 2-hydroxy-4-phenylbutyrate with an E = 39 under pH 5, 4 °C and 30% of acetonitrile. This work demonstrates the success of the combinatorial enzyme engineering for the production of highly enantioselective heterogeneous biocatalysts by screening different immobilization protocols and reaction media conditions.
Enzymatic Resolution by a d-Lactate Oxidase Catalyzed Reaction for (S)-2-Hydroxycarboxylic Acids
Sheng, Binbin,Xu, Jing,Ge, Yongsheng,Zhang, Shuo,Wang, Danqi,Gao, Chao,Ma, Cuiqing,Xu, Ping
, p. 2630 - 2633 (2016/08/30)
Oxidase-catalyzed kinetic resolution is important for the production of enantiopure 2-hydroxycarboxylic acids (2-HAs), which are versatile building blocks for the synthesis of many significant compounds. However, in contrast to that of (R)-2-HAs, the production of (S)-2-HA is challenging because of the lack of related oxidases. Herein, suitable enzymes were screened systematically through the analysis of numerous putative d-lactate oxidase sequences and identification of several required properties. Finally, a d-lactate oxidase from Gluconobacter oxydans 621H with advantageous characteristics, such as good solubility, broad substrate spectrum, and high stereoselectivity, was selected to resolve 2-HAs into (S)-2-HAs. A variety of (S)-2-HAs was produced successfully using this d-lactate oxidase with excellent enantiomeric excess values (>99 %). The presented screening criteria and approach for target biocatalysis suggested a guideline for the production of optically active chemicals such as (S)-2-HAs.
Asymmetric hydrogenation reaction of alpha-ketoacids compound
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Paragraph 0037; 0045, (2016/10/10)
The invention relates to the technical field of organic chemistry, especially to an asymmetric hydrogenation reaction of an alpha-ketoacids compound. The asymmetric hydrogenation reaction comprises a scheme shown in the description. In the scheme, R1 is phenyl, substituted phenyl, naphthyl, substituted naphthyl, C1-C6 alkyl, or aralkyl; a substituent group is C1-C6 alkyl, C1-C6 alkoxy, or halogen; and the number of the substituent group is 1-3. In the scheme, M is a chiral spiro-pyridylamino phosphine ligand iridium complex having a structure shown in the description. In the structure, R is hydrogen, 3-methyl, 4-tBu, or 6-methyl.
Direct asymmetric hydrogenation of α-keto acids by using the highly efficient chiral spiro iridium catalysts
Yan, Pu-Cha,Xie, Jian-Hua,Zhang, Xiang-Dong,Chen, Kang,Li, Yuan-Qiang,Zhou, Qi-Lin,Che, Da-Qing
supporting information, p. 15987 - 15990 (2015/02/19)
A new efficient and highly enantioselective direct asymmetric hydrogenation of α-keto acids employing the Ir/SpiroPAP catalyst under mild reaction conditions has been developed. This method might be feasible for the preparation of a series of chiral α-hydroxy acids on a large scale.
Highly enantioselective hydrogenation of 2-oxo-4-arybutanoic acids to 2-hydroxy-4-arylbutanoic acids
Zhu, Lufeng,Chen, Houhe,Meng, Qinghua,Fan, Weizheng,Xie, Xiaomin,Zhang, Zhaoguo
supporting information; experimental part, p. 6186 - 6190 (2011/09/19)
The Ru-catalyzed asymmetric hydrogenation of 2-oxo-4-arybutanoic acids to afford 2-hydroxy-4-arybutanoic acids was accomplished by employing SunPhos as chiral ligand and 1 M aq HBr as additive. The high enantioselectivities (88.4%-92.6% ee) and efficiency (TON=10,000, TOF=300 h-1) make this method efficient for the synthesis of an important intermediate, (R)-2-hydroxy-4-phenylbutanoic acid, for ACE inhibitors.