Applications of lipase-catalyzed kinetic resolution of (R,S)-naproxenyl 4-bromopyrazolide to prepare enantiomers
| Autor: | Yen Hua Chen, 陳彥樺 |
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| Rok vydání: | 2018 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 106 The aim of this study is to use methyl-α-D-glucopyranoside as an acyl acceptor for the kinetic resolution to (R,S)-naproxenyl 4-bromopyrazolide in organic solvents via Candida antarctica lipase B (CALB) and partially purified Carica papaya lipase (pCPL) to synthesize sugar ester enantiomers. In the first place, (R,S)-naproxenyl 4-bromopyrazolide was employed as the substrate for screening the best solvent, reaction temperature, and acyl acceptor from the resulting enzyme activity and enantioselectivity. The thermodynamic and kinetic analysis was then performed at the optimum condition. Finallly, the (S)-sugar ester product was separated from the remaining (R)-azolide substrate via their solubility difference. By choosing lipase CALB as the catalyst, the best condition was determined as: MTBE：tert-BuOH = 1：1, methyl-α-D-glucopyranoside as an acyl acceptor, temperature at 45℃, leading to the best enantiomeric ratio as 109.7. Thus, (S)-Naproxen could be prepared at high conversions. By choosing lipase pCPL as the catalyst, the best condition was determined as: isooctane: tert-BuOH = 95：5, temperature at 45℃, methyl-α-D-glucopyranoside as an acyl acceptor, leading to the best enantiomeric ratio as 41.1. Therefore, (S)-methyl 6-O-naproxenyl α-D-glucopyranoside could be prepared at low conversions of the substrate. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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