60827-45-4Relevant articles and documents
Enantioselective Resolution Copolymerization of Racemic Epoxides and Anhydrides: Efficient Approach for Stereoregular Polyesters and Chiral Epoxides
Li, Jie,Ren, Bai-Hao,Wan, Zhao-Qian,Chen, Shi-Yu,Liu, Ye,Ren, Wei-Min,Lu, Xiao-Bing
supporting information, p. 8937 - 8942 (2019/06/11)
Herein we report an efficient strategy for preparing isotactic polyesters and chiral epoxides via enantioselective resolution copolymerization of racemic terminal epoxides with anhydrides, mediated by enantiopure bimetallic complexes in conjunction with a nucleophilic cocatalyst. The chirality of both the axial linker and the diamine backbones of the ligand are responsible for the chiral induction of this kinetic resolution copolymerization process. The catalyst systems exhibit exceptional levels of enantioselectivity with a kinetic resolution coefficient exceeding 300 for various racemic epoxides, affording highly isotactic copolymers (selectivity factors of more than 300) with a completely alternating structure and low polydispersity index. Most of the produced isotactic polyesters are typical semicrystalline materials with melting temperatures in the range from 77 to 160 °C.
Immobilized Aspergillus niger epoxide hydrolases: Cost-effective biocatalysts for the prepation of enantiopure styrene oxide, propylene oxide and epichlorohydrin
Yildirim, Deniz,Tuekel, S. Seyhan,Alptekin, Oezlem,Alagoez, Dilek
, p. 84 - 90 (2013/08/24)
This study aimed to prepare robust immobilized epoxide hydrolase (EH) preparations for asymmetric hydrolysis of racemic epoxides such as styrene oxide, propylene oxide and epichlorohydrin. For this purpose, Aspergillus niger EH was immobilized onto Lewatit VP OC 1600 support by adsorption, modified Florisil and Eupergit C supports by covalently. The suitability of the supports was examined for protein binding capacity and rate of racemic styrene oxide hydrolysis. The protein-activity recovery yields were 75-85%, 82-78% and 90-75%, respectively for EH immobilized onto Lewatit VP OC 1600, modified Florisil and Eupergit C supports. All A. niger EH preparations catalyzed preferentially hydrolysis of (R)-epoxides. Although enantiomeric excess values of all the tested epoxides were 99%, the highest enantiopure epoxide yields were obtained as 48% for (S)-styrene oxide by the immobilized EHs onto modified Florisil and Eupergit C. The highest diol yield was obtained as 78% for 3-chloro-1,2-propanediol, however, its enantiomeric excess value was 28.2%. Enantioselectivity of A. niger EH was improved with the preparation of mentioned immobilized forms. The highest enantioselectivity value was obtained as 95 toward styrene oxide by A. niger EH immobilized onto modified Florisil . The results of reusability studies show that the immobilized EH preparations offer feasible potentials for the preparation of enantiopure epoxides than that of free form.
P-Tolyl glycerol ether: Is it possible to find more simple molecular organogelator with pronounced chirality driven properties?
Bredikhin, Alexander A.,Bredikhina, Zemfira A.,Akhatova, Flyura S.,Gubaidullin, Aidar T.
supporting information; experimental part, p. 3523 - 3525 (2010/08/06)
p-Tolyl glycerol ether not belonging to any of the known gelator families forms stable transparent gels in hydrocarbon media showing very good quantitative characteristics of gelling abilities, which are, in turn, strongly dependent on the chiral characteristics of the gelator. The crystal packing differences between the rac- and scal-substances could be the reason for such behaviour.