78% |
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(S) -amino-butyric acid methyl ester hydrochloride, 300 mL of methanol and 42 g of potassium borohydride were subjected to a reduction reaction in the same manner as in Example 11 to give 3 (S) -amino-1- Butanol (IV) as a colorless viscous liquid, 27.1 g,Rate of 78percent, ee value of 99.2percent, content of 99.1percent (GC method) 60 g of ethyl 3 (R) -aminobutyrate hydrochloride 63 mL of a 50percent aqueous solution of sodium hydrogencarbonate was carefully added with cooling with ice-water bath. After stirring for 15 minutes, the mixture was extracted three times with dichloromethane (100 mL x 3) , Dried over anhydrous sodium sulfate, filtered and concentrated to dryness (recovered methylene chloride can be applied in the same procedure as described in the next reaction). After adding 300 mL of ethanol to the residue,40 g of potassium borohydride was added in portions at room temperature with stirring, and the reaction was continued at room temperature with stirring,TLC follow the test, about 12 hours of complete reaction, vacuum distillation of ethanol recovery (the next batch reaction in this step the same procedure applied), to the residue by adding 200mL of water, stirring at room temperature with 2N hydrochloric acid carefully adjust PH value to 3- 4, washed three times with dichloromethane (100mL x 3), (combined washing liquid, by distillation of dichloromethane recovery, in the next batch of this step in the same application)The aqueous phase was then adjusted to pH 9 with 2N aqueous sodium carbonate solution, evaporated to dryness under reduced pressure,150 mL of absolute ethanol was added,After thorough stirring, filtration,And then washed with 50mL absolute ethanol filter cake,The organic phases were combined,The ethanol was recovered by distillation at atmospheric pressure (the ethanol fraction was recovered by combining the pre-distillate from the vacuum distillation product,In the next batch of reaction to the same procedure used in this step),Then vacuum distillation,The 59-60 ° C / 10 mm Hg fraction was collected,To give 3 (R) -amino-1-butanol (IV),Colorless viscous liquid, 24.5 g, yield 77percent, ee value 99.2percent, content 99.1percent (GC method) |