53439-96-6Relevant articles and documents
Preparation method for key intermediate of Barnidipine
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Paragraph 0058; 0060-0061; 0070; 0072-0073; 0082; 0084-0085, (2019/10/07)
he preparation method of the intermediate is characterized by comprising the following steps: with chiral hydroxy acid as a starting material, the chiral hydroxy acid reacts with isopropanol under the catalysis of lewis acid, then reacts with an acetoacetic acid reagent, and is directly cyclized with m-nitrobenzaldehyde and methyl 3-aminocrotonate in an alcohol solvent, then crystallization is performed in a low temperature environment for realizing chiral resolution, hydrolysis is performed by sodium hydroxide, and then acidization is performed by hydrochloric acid to obtain a product. the intermediate is characterized by being prepared by the following steps: with chiral hydroxy acid as a starting material,the chiral hydroxy acid reacts with isopropanol under the catalysis of lewis acid, then reacts with an acetoacetic acid reagent, and is directly cyclized with m-nitrobenzaldehyde and methyl 3-aminocrotonate in an alcohol solvent, crystallization and chiral resolution are realized in a low temperature environment, hydrolysis is performed by sodium hydroxide, and then acidization is performed by hydrochloric acid to obtain a product. The preparation method disclosed by the invention has the advantages that the preparation technology is simple, the resolution is easy, the product yield is high, the optical purity is good, the quality is stable, and the large-scale industrial production is easy.
Chiral-at-Iron Catalyst: Expanding the Chemical Space for Asymmetric Earth-Abundant Metal Catalysis
Hong, Yubiao,Jarrige, Lucie,Harms, Klaus,Meggers, Eric
supporting information, p. 4569 - 4572 (2019/03/19)
A new class of chiral iron catalysts is introduced that contains exclusively achiral ligands with the overall chirality being the result of a stereogenic iron center. Specifically, iron(II) is cis-coordinated to two N-(2-pyridyl)-substituted N-heterocycli
Dual pathway for the asymmetric transfer hydrogenation of α-ketoimides to chiral α-hydroxy imides or chiral α-hydroxy esters
Zhao, Qiankun,Zhao, Yuxi,Liao, Hang,Cheng, Tanyu,Liu, Guohua
, p. 412 - 416 (2016/02/05)
In an enantioselective reaction, we expect to obtain two types of chiral products through a controllable strategy in asymmetric catalysis. Herein, we develop Ru-catalysed asymmetric transfer hydrogenation of α-ketoimides to realise an enantioselective construction of chiral α-hydroxy imides or chiral α-hydroxy esters. The transformation of α-ketoimides catalysed by (S,S)-[RuCl(η6-mesitylene)diamine] can afford various chiral α-hydroxy imides with high yields and enantioselectivities, whereas that catalysed by (S,S)-[RuCl(η6-hexamethylbenzene)diamine] gives the desirable chiral α-hydroxy esters through a slight adjustment of the reaction conditions. The method described here is a controllable organic transformation with sodium formate as a hydrogen source under mild reaction conditions, and the benefit of this transformation is that various chiral α-hydroxy imides or α-hydroxy esters can be obtained selectively from α-ketoimides. Selective directive: An enantioselective transformation in the Ru-catalyzed asymmetric transfer hydrogenation of α-ketoimides to chiral α-hydroxy imides or α-hydroxy esters is developed. The transformation of α-ketoimides catalyzed by (S,S)-[RuCl(η6-mesitylene)diamine] can afford various chiral α-hydroxy imides with high yields and enantioselectivities, whereas that catalyzed by (S,S)-[RuCl(η6-hexamethylbenzene)diamine] give desirable chiral α-hydroxy esters through a slight adjustment of reaction conditions.
