143615-00-3Relevant articles and documents
Utilization of (18-Crown-6)-2,3,11,12-tetracarboxylic Acid as a Chiral NMR Solvating Agent for Diamines and β-Amino Acids
Rodriguez, Yolanda C.,Duarte, Tayla M.,Szakonyi, Zsolt,Forr?, Eniko,Fül?p, Ferenc,Wenzel, Thomas J.
, p. 708 - 715 (2015/10/12)
The compound (18-crown-6)-2,3,11,12-tetracarboxylic acid was evaluated as a chiral nuclear magnetic resonance (NMR) solvating agent for a series of diamines and bicyclic β-amino acids. The amine must be protonated for strong association with the crown ether. An advantage of (18-crown-6)-2,3,11,12-tetracarboxylic acid over many other crown ethers is that it undergoes a neutralization reaction with neutral amines to form the protonated species needed for binding. Twelve primary diamines in neutral and protonated forms were evaluated. Diamines with aryl and aliphatic groups were examined. Some are atropisomers with equivalent amine groups. Others have two nonequivalent amine groups. Association equilibria for these systems are complex, given the potential formation of 2:1, 1:1, and 1:2 crown-amine complexes and given the various charged species in solution for mixtures of the crown ether with the neutral amine. The crown ether produced enantiomeric differentiation in the 1H NMR spectrum of one or more resonances for every diamine substrate. Also, a series of five bicyclic β-amino acids were examined and (18-crown-6)-2,3,11,12-tetracarboxylic acid caused enantiomeric differentiation in the 1H NMR spectrum of three or more resonances of each compound. Chirality 27:708-715, 2015.
Bioresolution production of (2R,3S)-Ethyl-3-phenylglycidate for chemoenzymatic synthesis of the taxol C-13 side chain by galactomyces geotrichum ZJUTZQ200, a new epoxide-hydrolase-producing strain
Wei, Chun,Ling, Jinlong,Shen, Honglei,Zhu, Qing
, p. 8067 - 8079 (2014/07/08)
A newly isolated Galactomyces geotrichum ZJUTZQ200 strain containing an epoxide hydrolase was used to resolve racemic ethyl 3-phenylglycidate (rac-EPG) for producing (2R,3S)-ethyl-3-phenylglycidate ((2R,3S)-EPG). G. geotrichum ZJUTZQ200 was verified to be able to afford high enantioselectivity in whole cell catalyzed synthesis of this chiral phenylglycidate synthon. After the optimization of the enzymatic production and bioresolution conditions, (2R,3S)-EPG was afforded with high enantioselectivity (e.e.S > 99%, E > 49) after a 8 h reaction. The co-solvents, pH buffer solutions and substrate/cell ratio were found to have significant influences on the bioresolution properties of G. geotrichum ZJUTZQ200. Based on the bioresolution product (2R,3S)-EPG, taxol's side chain ethyl (2R,3S)-3-benzoylamino-2-hydroxy- 3-phenylpropionate was successfully synthesized by a chemoenzymatic route with high enantioselectivity (e.e.S > 95%).
Highly diastereoselective and enantioselective synthesis of α-hydroxy β-amino acid derivatives: Lewis base catalyzed hydrosilylation of α-acetoxy β-enamino esters
Jiang, Yan,Chen, Xing,Zheng, Yongsheng,Xue, Zhouyang,Shu, Chang,Yuan, Weicheng,Zhang, Xiaomei
, p. 7304 - 7307 (2011/09/16)
By design: A series of α-acetoxy-β-enamino esters 1 were synthesized and then subjected to catalytic asymmetric hydrosilylation. In the presence of a chiral Lewis base catalyst, the reactions proceeded smoothly to provide a wide range of chiral α-acetoxy β-amino acid derivatives in high yields with good diastereoselectivities and enantioselectivities. Copyright
