Citric Acid → (2S,3S)-1,2-Epoxy-3-(Cbz-amino)-4-phenylbutane

To a suspension of 196.7 g of the N-benzyloxycarbonyl-3(S)-amino-2(R)-methanesulfonyloxy-4-phenyl-1-butanol obtained in the above Example 3 in 2,500 ml of methanol was added 90 g of potassium carbonate. The obtained mixture was then stirred at room temperature for 5 hours. The pH value of the reaction mixture was adjusted to 7 with a 10% aqueous solution of citric acid. Then the solvent was concentrated under reduced pressure. After adding water to the residue, it was extracted with ethyl acetate. The organic layer was washed with a saturated aqueous solution of sodium chloride. After adding anhydrous sodium sulfate and activated carbon, the mixture was filtered. Then the filtrate was concentrated and n-hexane was added thereto for crystallization. The crystals thus precipitated were filtered and dried. Thus the target N-benzyloxycarbonyl-3(S)-amino-1,2(S)-epoxy-4-phenylbutane was obtained in the form of white crystals. The overall yield of Referential Example 2 and Example 3 through Example 4 was 72.3%.

1. concentrationThen the solvent was concentrated under reduced pressure
2. additionAfter adding water to the residue, it
3. extractionwas extracted with ethyl acetate
4. washThe organic layer was washed with a saturated aqueous solution of sodium chloride
5. additionAfter adding anhydrous sodium sulfate and activated carbon
6. filtrationthe mixture was filtered
7. concentrationThen the filtrate was concentrated
8. additionn-hexane was added
9. customfor crystallization
10. customThe crystals thus precipitated
11. filtrationwere filtered
12. customdried

ORD record

ord-eb23e7cadc6a4af2ba7b49686ecd7cce

Source dataset

uspto-grants-1996_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05488118