Enhancement of enantioselectivity and reaction rate on the synthesis of (S)-ketoprofen hydroxyalkyl ester in organic solvents via isopropanol-dried immobilized lipase
✍ Scribed by Chun-Sheng Chang; Chin-Shuo Hsu
- Publisher
- Wiley (John Wiley & Sons)
- Year
- 2005
- Tongue
- English
- Weight
- 151 KB
- Volume
- 80
- Category
- Article
- ISSN
- 0268-2575
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✦ Synopsis
Abstract
Lipase‐catalyzed enantioselective esterification between (R,S)‐ketoprofen and alkanediol in organic solvents was developed to produce (S)‐ketoprofen hydroxyalkyl esters. The acyl acceptor of 1,6‐hexanediol for the resolution of (R,S)‐ketoprofen yielded only the enantioselectivity (the enantiomeric ratio of initial rate for (S)‐ketoprofen to that of (R)‐ketoprofen) V~S~/V~R~ = 8, when crude Lipase MY originating from Candida rugosa was used. However, isopropanol‐dried immobilized lipases (IPA‐dried IM‐lipase) effectively enhanced the enantioselectivity to greater than 20 in the esterification of (R,S)‐ketoprofen when 1,4‐butanediol, 1,5‐pentanediol or 1,6‐hexanediol was employed. IPA‐dried IM‐lipase and isooctane were selected to use for optimally immobilized lipase and reaction medium, respectively. The IPA‐dried IM‐lipase exhibited the highest enantioselectivity, E = 26.7, to the (S)‐enantiomer with 1,5‐pentanediol and the best enzyme activity to the (S)‐enantiomer with 1,4‐butanediol. The finding indicates that the carbon chain length of the alkanediol strongly affected the enzyme activity and enantioselectivity of lipase‐catalyzed esterification. A maximum enantioselectivity of 37 at 27 °C was generated by IPA‐dried IM‐lipase for the enantioselective esterification of racemic ketoprofen with 1,4‐butanediol. IPA‐dried IM‐lipase can effectively increase the enantioselectivity of lipase. Copyright © 2005 Society of Chemical Industry