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1
Synthesize Find similar With potassium borohydride in methanol; water
T=-10 - -5°C; Inert atmosphere; Hide Experimental Procedure
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Rx-ID: 45012213
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Zhejiang Apeloa Kangyu Pharmaceutical Co., Ltd.; Wang, Zheqing; Ge, Mengya; Ye, Zengfaang; Shu, Lijian; Zheng, Liangrong; Fang, Meifen; Sun, Yunlei; Zhang, Kehua
Patent: CN106008183 A, 2016 ; Location in patent: Paragraph 01021; 0122; 0123 ; Title/Abstract Full Text Show Details
10:Example 10
(S) - (-) - 2-methylamino-1-phenyl-acetone-DBTA complex salt (233.2 g, 0.34 mol) was placed in a reaction flask under nitrogen.A 50percent by volume aqueous solution of methanol (700 ml) was added and stirred at room temperature to form a clear solution.Cooled to -10 to -5 ° C and then adding potassium borohydride powder and maintaining the same low temperature reaction for 30 to 60 minutes.HPLC showed the disappearance of the starting material, the reaction was concentrated under reduced pressure and evaporated to dryness. Ice water (500 ml) was added to the residue, and then 5N concentrated hydrochloric acid was added dropwise to pH = 1.0.The precipitated (-) - DBTA was extracted twice with ethyl acetate.A 10 N aqueous solution of sodium hydroxide was added dropwise to an acidic aqueous solution which had been cooled to 0 to 5 ° C until pH = 12.The precipitated oil was extracted three times with toluene.The combined organic phases were washed once with water and once with saturated brine.5N hydrochloric acid was added dropwise to a toluene solution to pH = 5-6 and stirred for 15 minutes.The layers were separated and concentrated under reduced pressure to dryness to give ephedrine (1) hydrochloride (124.6 g, 91.1percent, specific rotation -34.5 °).