Ammonium Chloride → Butyl (2S)-2-hydroxybutanoate

Under argon, copper(I) iodide (594 mg) was suspended in anhydrous diethyl ether (20.0 mL). A solution of methylmagnesium bromide in anhydrous tetrahydrofuran (60.2 mL, M) was added dropwise to the suspension at −15° C. or lower, and the mixture was allowed to react at the same temperature for 20 minutes. After completion of reaction, a solution (8.0 mL) of n-butyl(S)-(−)-2,3-epoxypropionate (3.0 g, 97.3% ee) (product of Osaka Organic Chemical Industry Co., Ltd.) in anhydrous diethyl ether was added dropwise to the reaction mixture at −78° C., and the resultant mixture was allowed to react for 15 minutes at the same temperature. After completion of reaction, an aqueous saturated ammonium chloride solution (50.0 mL) was added to the reaction mixture, followed by filtration by means of a Celite. The filtrate was extracted twice with diethyl ether (50 mL×2), and the organic layer was washed with saturated brine (40 mL). The washed organic layer was dried over sodium sulfate anhydrate and concentrated under reduced pressure. The residue was subjected to silica gel column chromatography including elution with methylene chloride/diethyl ether=5/1, to thereby yield 3.37 g of colorless oil (yield 99.0%). Since the compound was also able to be purified through distillation under reduced pressure, another aliquot of the residue obtained through the same procedure was distillated under reduced pressure, to thereby yield 2.73 g of colorless oil (yield 81.8%).

1. customto react at the same temperature for 20 minutes
2. customAfter completion of reaction
3. customto react for 15 minutes at the same temperature
4. customAfter completion of reaction
5. filtrationfollowed by filtration by means of a Celite
6. extractionThe filtrate was extracted twice with diethyl ether (50 mL×2)
7. washthe organic layer was washed with saturated brine (40 mL)
8. dry with materialThe washed organic layer was dried over sodium sulfate anhydrate
9. concentrationconcentrated under reduced pressure
10. washelution with methylene chloride/diethyl ether=5/1

ORD record

ord-2da33b68edab4b658e0aed2d131b3a09

Source dataset

uspto-grants-2010_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07767845B2