| Autor: |
Falus, Péter, Cerioli, Lorenzo, Bajnóczi, Gabriella, Boros, Zoltán, Weiser, Diána, Nagy, József, Tessaro, Davide, Servi, Stefano, Poppe, László |
| Předmět: |
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| Zdroj: |
Advanced Synthesis & Catalysis; 5/19/2016, Vol. 358 Issue 10, p1608-1617, 10p |
| Abstrakt: |
Alcalase® (Subtilisin A) was immobilized by simple hydrophobic adsorption onto various surface-grafted macroporous silica gels resulting in easy-to-prepare and stable biocatalysts enabling the efficient kinetic resolution (KR) and dynamic kinetic resolution (DKR) of racemic N-Boc-phenylalanine ethyl thioester with benzylamine. The immobilized Alcalase biocatalysts, which retained their activity and selectivity when stored at 4 °C for more than a year, were tested in enzymatic aminolysis in batch and continuous-flow KRs resulting in ( S)- N-Boc-phenylalanine benzylamide in high enantiomeric purity. In KR of the racemic thioester by Alcalase-catalyzed aminolysis in a continuous-flow reactor, the productivity (specific reaction rate, rflow) and enantiomeric ratio ( E) were studied in the 0-100 °C range. The effect of the temperature on base-catalyzed racemization of the non-transformed ( R)-thioester in a continuous-flow reactor was also investigated in the 0-150 °C range. The continuous-mode DKR of the racemic thioester in a serial cascade system of six biocatalyst-filled columns at 50 °C for KR and five grafted silica gel-filled columns at 150 °C for racemization resulted in the formation of the ( S)-benzylamide in 79% conversion, 8.17 g L−1 h−1 volumetric productivity and 98% ee. This is the first example of a dynamic kinetic resolution of an amino acid derivative in continuous-flow mode using an alternating cascade of packed-bed enzyme reactors and racemization reactors kept at different temperatures. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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