Description
(S)-1,1,1-Trifluoro-2-propanol is a compound important as an intermediate for various medicines and agrichemicals. Aside from methods using chemical catalysts, biological methods of reducing 1,1,1-trifluoroacetone to (S)-1,1,1-trifluoro-2-propanol by having microbial enzymes act on 1,1,1-trifluoroacetone has hitherto been studied.
Uses
(S)-1,1,1-TRIFLUORO-2-PROPANOL can be used as organic synthesis intermediates and pharmaceutical intermediates, mainly used in laboratory research and development and chemical production processes.
Synthesis
A liquid medium was prepared to be composed of 2000 ml of an ion-exchanged water, 60 g of glucose, 30 g of peptone, 50 g of yeast extract, 4.8 g of potassium dihydrogenphosphate and 2.5 g of dipotassium hydrogen phosphate. The liquid medium was charged into a fermenter of 5 L capacity (available from B.E. MARUBISHI Co., Ltd. under the trade name of a MDN-type 5L(S)) and then subjected to steam sterilization at 121°C for 60 minutes. This liquid medium was inoculated with 80 ml of a suspension of Hansenula polymorpha NBRC0799, the suspension being obtained by conducting a preliminary culture on 100 ml of the same composition to be 2.0 × 109 cfu/ml. Then, it was cultured at 28°C, an air ventilation of 1 vvm and a stirring speed of 500 rpm for 24 hours, thereby preparing a suspension of 4.3 × 109 cfu/ml (or 86 g/L in terms of the weight of wet cell bodies). At this time, adjustment of pH was attained by using aqueous ammonia, so that a pH was adjusted at 6.5. After culture had terminated, the ventilation amount and the stirring speed were changed to 0.1 vvm and 50 rpm. A solution obtained by dissolving 125.2 g of 1,1,1-trifluoroacetone and 200 g of glucose in 300 ml of an ion-exchanged water prepared in another vessel was added to the suspension automatically by a computer program in the use of an online sugar concentration sensor (an online biosensor available from ABLE & Biott Co.,Ltd. under the trade name of BF-410), so as to maintain a glucose concentration of 2 %. It was confirmed that the yield obtained after a lapse of 168 hours was 94.9 % by monitoring the reduction of the substrate due to the microorganism every 24 hours, upon which the reaction was terminated.
In order to recall 1,1,1-trifluoro-2-propanol produced from the reaction solution after termination of the reaction, distillation was performed. A distillate was recalled in an amount of 188 ml, from which it was found, by internal standard method of 19F-NMR, that 109.2 g of 1,1,1-trifluoro-2-propanol was contained. As a result of measuring the optical purity under the above-discussed analyzing conditions, the optical purity was confirmed to be 98.7% ee (S-configuration).
