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題名 | Side-Reaction Effects on Dynamic Kinetic Resolution by Enzyme-Catalyzed Irreversible Acyl Transfer=副反應對酵素進行不可逆醯基轉化動態動力分割之影響 |
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作者 | 鄭育奇; 蔡少偉; Cheng, Yu-chi; Tsai, Shau-wei; |
期刊 | Journal of the Chinese Institute of Chemical Engineers |
出版日期 | 20030700 |
卷期 | 34:4 2003.07[民92.07] |
頁次 | 頁457-469 |
分類號 | 460.02 |
語文 | eng |
關鍵詞 | 副反應; 酵素; 不可逆醯基轉化動態動力分割; Dynamic kinetic resolution; Thiotransesterification; Hydrolysis; Esterification; Lipase; (S)-Naproxen ester; |
中文摘要 | 本文提出一個分析解,探討以酵素為觸媒進行不可逆醯基轉化動態動力分割系統中副反應對目標對掌性異構物產量及光學純度之影響。此外,以脂肪酵素進行(R,S)-naproxen 2,2,2-trifluoroethyl thioester與4-morpholine ethanol之轉硫酯化動態動力分割為範例,進一步比較理論預測與實驗結果間差異。在控制異辛烷溶液中之初始水含量為0.113下,發現添加消旋觸媒三辛基胺對酵素水解副反應、酵素對醇與水之選擇性有重大影響。理論分析顯示若酵素對水解及酯化副反應有較好之反應性與立體選擇性時,副反應將有助於增加目標對掌性異構物產量及光學純度,此結果特別適合於消旋速率較快之反應系統。 |
英文摘要 | An analytical solution for the dynamic kinetic resolution of enzyme-catalyzed irreversible acyl transfer was employed to study the side-reaction effects on the yield and optical purity of the desired enantiomeric product. A lipase-catalyzed enantioselective thiotransesterification between (R,S)-naproxen 2,2,2-trifluoroethyl thioester and 4-morpho-line ethanol with in situ racemization of (R)-thioester using trioctylamine as the racemization catalyst in isooctane was designed as a model system to compare the theoretical predictions. Under an initial water activity of 0.113, adding trioctylamine was found to have profound effects on the hydrolysis side-reactions, thus enhancing the chemoselectivity of the lipase to the alcohol in comparison with water. Theoretical analysis also indicated that the time-course yield and the enantiomeric excess for the desired enantiomer could be improved if the employed lipase had higher activity and enantioselectivity for the hydrolysis and esterification side-reactions, especially when the base had a similar racemization rate compared with the rate of the fast-reaction substrate. |
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