| Enantiopure N-substituted phenyl α-alanines are important intermediates for the chiral synthesis, especially in the field of chiral pesticides. The most commonly used methodology for the preparation of enantiopure N-substituted phenyl α-alanine is chemical resolution, but the method of chemistry have some disadvantages.The main purpose of this research is enantioselective hydrolysis of N-substituted phenyl α-alanine by using lipase as the catalyst. Optimum reaction conditions are achieved. The influence on lipase activity and enantioselectivity by immobilization of lipase and addition of different additives to the reaction system is studied. The mechanism of the enantioselective lipase-catalyzed hydrolysis is explained based on the molecular level. The application of enantiopure N-substituted phenyl α-alanine is also performed in the chemical synthesis. 1. Separation of N-substituted phenyl α-alanine by Capillary Electrophoresis　Capillary electrophoresis was firstly used for the chiral separation of N- (2-ethyl-6-methyl-Phenyl)-alanine(NEMPA) in this paper, using cyclodextrin as chiral additive. The effects of cyclodextrin type, variation of cyclodextrin concentration, background electrolyte pH, temperature and field strength were investigated. Optimum separation was achieved for NEMPA in 100 mmol/L triethylamine/acetic acid buffer, pH= 5.5, by using 40 mmol/L DM-β-CD as a buffer additive. The analysis was performed with applied voltage at 340V/cm, the temperature at 20℃ , sample concentration (50mg/L) and the absorbance was recorded at 200 nm. A new method of using capillary electrophoresis for the detection of enantiomeric excess of NEMPA has been established. The method is also applied to determin the enantiomeric excess of other N-substituted phenyl α-alanine.2. Lipase-catalyzed resolution of N-substituted phenyl α-alanineUsing (R, S)–NEMPA as a model compound, we herein have attempted to develop a stereoselectively hydrolytic process for studying the feasibility of resolution of the racemic N-substituted phenyl α-alanine via enzyme. The use of lipase as chiral catalyst to prepare enantiopure N-substituted phenyl α-alanine from the corresponding racemic esters has not been widely studied. The study focused on the identification of suitable lipases for enantiomeric resolution of (R, S)-NEMPA. Six kind of lipases were screened out for the enantioselective hydrolysis of racemic NEMPAME to yield chiral NEMPA. The screened lipase are CAL-B, PSL and BSL2.We further studied the influence of microenvironment on the lipase-catalyzed resolution and made comparison among the three lipases. The results suggest that the effects of the microenvironment on the activity and enantioselectivity of the three lipases are similar. The higher selectivity and activity of lipase could be achieved by operating at lower temperatures. In contrast, at higher temperatures, the reaction occurred with low enantiopreference. The E value and activity of the three lipases decreased in the pH range of alkalinity. The activity and enantioselectivity of BSL2 and PSL were influenced by the size of alkyl group of the ester moiety. According to the kinetic curve, the three lipases did not show the phenomena of interfacial activation and substrate inhibition under these assay conditions and the resolution of the lipase-catalyzed was controlled by kinetics entirely.3. Improve the activity and enantioselectivity of lipaseEffects of the organic solvent,detergent,macrocyclic polyamine and ionic liquid on the activity and enantioselectivity of CAL-B and BSL2 were studied in the reaction system, and the reasonable explainations for the effects were given. The effect of organic solvent on the activity and enantioselectivity of CAL-B and BSL2 is similar. Addition of certain organic solvent to the reaction mixture results in the improvement of enantioselectivity of lipases, whereas the activity of lipases are deteriorated. Diisopropyl ether and diethyl ether which are both belonged to the ether can drast...
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