Method for producing optically active 1-bromo-1-[3,5-bis(trifluoromethyl)phenyl] ethane
一种三氟甲基、光学活性的技术,应用在1-溴-1-[3,5-双(三氟甲基)苯基]乙烷的制备领域,能够解决无法稳定地供给光学活性体、反应性高等问题
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[0043] The method of the present invention is a preparation method of optically active 1-bromo-1-[3,5-bis(trifluoromethyl)phenyl]ethane, which is characterized in that it comprises the following steps: using a) phosphorus halide and hydrogen bromide The combination of b) 1,2-dibromo-1,1,2,2-tetrachloroethane and the general formula (I): P(R 1 )(R 2 )(R 3 ) (where, R 1 , R 2 , and R 3 independently represent C 6-10 Aryl, C 6-10 Aryloxy, C 1-10 Alkyl, C 1-10 Alkoxy, C 3-6 Cycloalkyl, or C 3-6 Cycloalkoxy) a combination of organophosphorus compounds, or c) any one of the combinations of N-bromosuccinimide and dialkyl sulfide as a brominating agent for brominating optically active 1-[3 ,5-bis(trifluoromethyl)phenyl]ethanol. In the case of using a combination of (b) or (c) above as a brominating agent, it is preferable to carry out the reaction in the presence of a solvent.
[0044] The optically active 1-[3,5-bis(trifluoromethyl)phenyl]ethanol used as a raw material in...
Embodiment
[0066] Hereinafter, the present invention will be described in more detail through examples, but the scope of the present invention is not limited by these examples.
[0067] The absolute configuration of 1-bromo-1-[3,5-bis(trifluoromethyl)phenyl]ethane shown in Example 1 below is converted to Commercially available α-[3,5-bis(trifluoromethyl)phenyl]ethanamine whose absolute configuration is known was determined by comparing the signs of the specific rotation. In addition, the desired optical purity of 1-bromo-1-[3,5-bis(trifluoromethyl)phenyl]ethane was analyzed by chiral HPLC (CHIRALPAK (registered trademark) AS-RH; mobile phase: ethanol / Water = 60 / 40; flow rate: 0.5mL / min; column temperature: 25°C; detection wavelength: 220nm; retention time: first peak / (R) 21.8min, second peak / (S) 26.0min).
[0068] As (S)-1-[3,5-bis(trifluoromethyl)phenyl]ethanol, (S)-1-[3,5-bis(trifluoromethyl)phenyl]ethanol with an optical purity of 99.5% and 98% was used ) phenyl] ethanol, for the p...
example 1-1
[0070] Under argon atmosphere, drop in (S)-1-[3,5-bis(trifluoromethyl)phenyl]ethanol (1.0g, 3.87mmol, >99.5%ee) on a water bath below 20°C Add phosphorus tribromide (0.52g, 1.94mmol), and stir at 19-22°C for 30 minutes. The reaction solution was cooled, hydrogen bromide (30% acetic acid solution) (0.76 mL, 3.87 mmol) was added dropwise below 0°C, and stirred at 13-15°C for 18 hours. The reaction solution was poured into ice water, and extracted with n-hexane (15 mL×2). The combined organic layers were washed with saturated aqueous sodium bicarbonate solution (15 mL×1), followed by saturated brine (15 mL×1), dried over anhydrous sodium sulfate, and concentrated under reduced pressure. The obtained crude product was purified by column chromatography (silica gel 8 g, eluent: n-hexane) to obtain 1.06 g of (R)-1-bromo-1-[3,5-bis(trifluoro Methyl)phenyl]ethane.
[0071] Yield: 85%
[0072] Chiral HPLC analysis: optical purity 96.8%ee (first peak), conversion rate 97.3%
[0073]...
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