(S)-3,5-Bistrifluoromethylphenyl ethanol((S)-BTPE) is a key pharmaceutical intermediate of the NK-1 receptor antagonist. The asymmetric bioreduction of 3,5-bis(trifluoromethyl) acetophenone (BTAP) to (S)-BTPE using Rhodococcus erythropolis XS1012 has been established in a phosphate buffer system. To overcome the problem of unsatisfactory yields at high substrate concentration, deep eutectic solvents (DESs) have been introduced to the buffer system. After screening 13 kinds of choline chloride-based DESs, [choline chloride][urea] ([ChCl][U]) showed great influence on the cell activity and significantly increased the cell membrane permeability. Subsequently, some major parameters for this reaction were determined. A remarkable (S)-BTPE yield of 91.9% was gained at 150 mM substrate concentration under optimized reaction conditions with >99.9% product enantioselectivity. Compared to reduction in a buffer system, the developed [ChCl][U]-containing system increased the yield from 82.6% to 91.9%. It maintains a yield of 80.7% with the substrate concentration up to 300 mM, compared to only 63.0% in buffer system. This study demonstrated that [ChCl][U] is a feasible co-solvent to improve the bioreduction process.
A new type of sensitiser, sodium benzenesulphinate (SBS), was used for sensitisation of water coated photothermographic (PTG) materials which were made up of ex situ AgBr, silver stearate (AgSt), polyvinyl alcohol and other functional components. The experimental results showed that (a) the sensitisation capability of SBS to PTG materials was quite effective and the maximal sensitivity relative to the unsensitised one could be increased by 30 times; (b) that the mode of sensitisation by SBS which sensitised single ex situ AgBr was better than those by SBS which sensitised either the single AgSt or the mixture of (AgBrzAgSt) in sensitivity improvement of PTG materials; (c) that the improvement in sensitivity, in addition, was dependent on sensitisation temperature and time as well as the amount of SBS.
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