Synlett 2025; 36(07): 853-858
DOI: 10.1055/a-2417-1017
letter

Synthesis of 6-Hydroxy-8-chlorooctanoate Ethyl Ester by Chemoenzymatic Method

Zhengdong Ding
,
Hongbin Zhang
This research was supported by the Natural Science Foundation of Anhui Province (grant no. 2308085MC110). The authors are grateful to the Natural Science Foundation of Anhui Province for financial support.


Abstract

6-Hydroxy-8-chlorooctanoate ethyl ester, an intermediate of α-lipoic acid, was synthesized via a chemoenzymatic method. High-throughput screening revealed that keto reductase HGD-1 could effectively catalyze the preparation of 6-hydroxy-8-chlorooctanoate ethyl ester, achieving a substantial conversion rate. The reaction conditions were optimized subsequently, the parameters for the complexation reaction were established as follows: a weight of AlCl3 1.8 times that of the substrate; a reaction time of 4 h; a temperature range of 20–25 °C. The parameters for the enzyme-catalyzed reaction were as follows: a temperature range of 25–30 °C; a reaction time of 4 h; a solution pH of 6.5–7.5; a substrate concentration of 50 g/L; concentrations of keto reductase HGD-1, coenzyme glucose dehydrogenase, and nicotinamide adenine dinucleotide phosphate of 3 g/L, 4 g/L, and 0.05 g/L, respectively. Under these optimal conditions, the substrate conversion rate exceeded 95%, and 92% yield of 6-hydroxy-8-chlorooctanoate ethyl ester is obtained, suggesting a viable, eco-friendly method for synthesizing α-lipoic acid, and it provides a green process route for the industrial production of α-lipoic acid.

Supporting Information



Publikationsverlauf

Eingereicht: 15. Juni 2024

Angenommen nach Revision: 17. September 2024

Accepted Manuscript online:
17. September 2024

Artikel online veröffentlicht:
14. Oktober 2024

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