Metal ions dramatically enhance the enantioselectivity for lipase-catalysed reactions in organic solvents
作者:Takashi Okamoto、Ebara Yasuhito、Shin-ichi Ueji
DOI:10.1039/b514885e
日期:——
simple and a powerful method to enhance the enantioselectivity for lipase-catalysed transformations in organicsolvents by an addition of metal ion-containing water to the reaction mixture. In this paper, various metal ions such as LiCl or MgCl2 are tested to improve the enantioselectivity for the model reactions. The enantioselectivities obtained are dramaticallyenhanced, the E values of which are about
improvement of the enantioselectivity of lipase-catalyzed hydrolysis of butyl 2-(4-substitutedphenoxy)propanoates in an aqueous buffer solution. On the other hand, lipase lyophilized from an aqueous solution containing the co-solvents catalyzed highly enantioselectiveesterification of 2-(4-substitutedphenoxy)propionicacids, 2-(4-isobutylphenyl)propionicacid (ibuprofen), and 2-(6-methoxy-2-naphthyl)propionic
添加共溶剂如四氢呋喃导致脂肪酶催化的 2-(4-取代苯氧基)丙酸丁酯在缓冲水溶液中水解的对映选择性大大提高。另一方面,从含有共溶剂的水溶液中冻干的脂肪酶催化 2-(4-取代苯氧基)丙酸、2-(4-异丁基苯基)丙酸(布洛芬)和 2-(6 -甲氧基-2-萘基)丙酸(萘普生)在有机溶剂中。对于某些底物,观察到 E 值增加了两个数量级。由共溶剂添加引起的对映选择性增强的起源主要归因于错误结合的对映异构体的初始反应速率显着减慢,与正确结合的对映体相比。从FT-IR、CD和ESR光谱的结果来看,还发现共溶剂的加入导致脂肪酶三级结构的部分破坏。
HPLC separation of 2-aryloxycarboxylic acid enantiomers on chiral stationary phases
作者:A. A. Tumashov、S. A. Vakarov、L. Sh. Sadretdinova、E. N. Chulakov、G. L. Levit、V. P. Krasnov、V. N. Charushin
DOI:10.1007/s11172-021-3165-8
日期:2021.5
reversed-phase HPLC on popular chiralstationaryphases. The best separation parameters were achieved on the chiralphases with the polysaccharide base Chiralcel OD-H and Chiralpack AD under the normal-phase HPLC conditions. The (S)- and (R)-enantiomers of 2-(1-naphthyloxy)- and 2-(2-iodophenoxy)propionic acids with enantiomeric excess ee >99% were isolated using preparative chiralHPLC.
Mutual Kinetic Resolution of Racemic 3,4-Dihydro-3-methyl-2<i>H</i>
-[1,4]benzoxazines with Acyl Chlorides of Racemic <i>O</i>
-Phenyllactic Acids and DFT Modelling of Transition States
作者:Marina A. Korolyova、Sergey A. Vakarov、Dmitry N. Kozhevnikov、Dmitry A. Gruzdev、Galina L. Levit、Victor P. Krasnov
DOI:10.1002/ejoc.201800656
日期:2018.9.9
The acylative kinetic resolution of 3,4‐dihydro‐3‐methyl‐2H‐[1,4]benzoxazines with racemic 2‐aryloxypropionyl chlorides has been studied experimentally and the geometries of the diastereoisomeric transition states determined by DFT calculations. It has been found that quantum chemical calculations describe well the quantitative dependence of the acylation selectivity on the reagents' structures.
The addition of sodium dodecyl sulfate (SDS) resulted in a dramatic improvement of the enantioselectivity of the lipasecatalyzed hydrolysis of racemic butyl 2-(4-substituted phenoxy)propanoates, racemic butyl 2-(4-isobutylphenyl)propanoate, and racemic butyl 2-(6-methoxy-2-naphthyl)propanoate in an aqueous buffer solution. An increase in the E value by up to two orders of magnitude was observed for some esters. As to the effects of SDS on the structure of a lipase, FT-IR and fluorescence measurements suggest some conformational change and/or an increase of the flexibility of the lipase, although the native secondary structure of the lipase is held even in the presence of 100 mM SDS. The origin of the enantioselectivity enhancement brought about by the addition of SDS is briefly discussed on the basis of the values of the initial rates obtained for each enantiomer of the substrate. (c) 2005 Elsevier Ltd. All rights reserved.