Hydrochloric Acid → (2R,3S)-3-(t-butoxycarbonyl)amino-4-phenyl-butane-1,2-diol

Temperature

20 °C

A solution of N-tert-butoxycarbonyl-3(S)-amino-2(R)-hydroxy-4-phenylbutyric acid methyl ester 99 g dissolved in ethanol 130 ml was kept at 15-25° C. and mixed with sodium borohydride 15.7 g and stirred at 15-25° C. for 2.5hrs. The reaction solution was diluted with water, adjusted with 6N-HCl to pH 2.5-3.5 and thereafter the solvent was distilled away to half the volume of the resultant solution, and then ethyl acetate was added to the solution. The solution thus obtained was washed with water and aqueous 10% sodium chloride solution successively to separate an organic phase. The solvent in the organic phase was distilled away and then ethyl acetate was added to the resultant concentrated solution to cool it and n-heptane was added to the solution halfway. Further n-heptane was added to the cloudy solution obtained. Thereafter, the solution was stirred at 10° C. to deposit crystals, which were filtered and dried in vacuum to obtain the N-tert-butoxycarbonyl-3(S)-amino-2(R)-hydroxy-4-phenyl-1-butanol(65.4 g).

1. customwas kept at 15-25° C.
2. distillationthe solvent was distilled away to half the volume of the resultant solution
3. additionethyl acetate was added to the solution
4. customThe solution thus obtained
5. washwas washed with water and aqueous 10% sodium chloride solution successively
6. customto separate an organic phase
7. distillationThe solvent in the organic phase was distilled away
8. additionethyl acetate was added to the resultant concentrated solution
9. temperatureto cool it and n-heptane
10. additionwas added to the solution halfway
11. additionFurther n-heptane was added to the cloudy solution
12. customobtained
13. stirringThereafter, the solution was stirred at 10° C.
14. filtrationwere filtered
15. customdried in vacuum

ORD record

ord-25f50bf5216e4d03ad277b2ecf42a8c8

Source dataset

uspto-grants-2002_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06376685B1