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S)-Duloxetine
Published in Peter Grunwald, Pharmaceutical Biocatalysis, 2019
Danish Shahzad, Muhammad Faisal, Aamer Saeed
(S)-2-(Dimethylamino)-1-(thiophen-2-yl)ethanol 29 is a famous precursor for synthesis of (S)-duloxetine 1. Intermediate 29 is synthesized from N-dimethyl-3-keto-(2-thienyl)-propanamine hydrochloride 28 in the yield of 81% and ee of >99%. Candida viswanathii in a fermentor (stirred tank bioreactor) as a biocatalyst at 30°C for 60 h (200 rpm) is employed for performing this reaction (Scheme 5.7) (Soni et al., 2008). They also investigated the required combination of pH, agitation and aeration processes that resulted in the remarkable improvement in the duration of microbial growth, both enzyme (carbonyl reductase) activity and its performance and productivity. In fact, agitation and aeration influenced the dissolved O2 concentration which in turn affected enzyme production as well as growth. Synthesis of 29 using Candida viswanathii in a fermentor.
Biotransformation of a crizotinib intermediate using a mutant alcohol dehydrogenase of Lactobacillus kefir coupled with glucose dehydrogenase
Published in Preparative Biochemistry and Biotechnology, 2019
Chuhong Zong, Xu Zhang, Fei Yang, Yafeng Zhou, Nan Chen, Zuisu Yang, Guofang Ding, Fangmiao Yu, Yunping Tang
Enzymatic reaction, enzyme activity, and stability are affected by temperature. Therefore, determination of the optimum reaction temperature is important.[21] As shown in Fig. 3, the conversion rate was approximately 91.3% at 25 °C, which increased to 100% at 30 or 35 °C. However, the conversion rate decreased rapidly (84.5% and 65.3% at 40 °C and 45 °C, respectively) when the temperature increased above 40 °C. It was speculated that the increase in temperature increases the thermal energy of the substrate molecules and make them more likely to diffuse around the enzyme molecules.[20] However, the conversion rate decreased while the temperature kept rising from 40 °C to 45 °C, which may be related to the partial denaturation of the enzyme at higher temperatures. As the lower temperature is conducive for enzyme stability, the optimum temperature was considered as 30 °C, which was similar to the optimum temperature of carbonyl reductase from Novosphingobium aromaticivorans[13] or Rhodosporidium toruloides.[14]