Hydrochloric Acid → (S)-2-amino-4-methyl-hexanoic acid ethyl ester hydrochloride

A solution of (S)-2-(benzhydrylidene-amino)-4-methyl-hexanoic acid (5.09 g, 15.1 mmol) in tetrahydrofuran (100 mL) was treated with a 2N aqueous hydrochloric acid solution (50 mL) and stirred at room temperature for 1.5 hr. The mixture was concentrated in vacuo and the residue partitioned between methyl t-butyl ether and water. The layers were separated and the aqueous phase was washed with methyl t-butyl ether. The organic phases were discarded and the aqueous phase neutralized with a 1N aqueous sodium hydroxide solution (150 mL) and extracted with methyl t-butyl ether. The combined organic layers were washed with brine and dried over anhydrous sodium sulfate. The mixture was concentrated in vacuo and the residue was dissolved in diethyl ether (20 mL). The diethyl ether solution was treated with 3M hydrogen chloride in diethyl ether (10 mL) and the mixture concentrated in vacuo. The residue was triturated with diethyl ether and hexanes which afforded (S)-2-amino-4-methyl-hexanoic acid ethyl ester hydrochloride (2.30 g, 73%) as a white solid.

1. concentrationThe mixture was concentrated in vacuo
2. customthe residue partitioned between methyl t-butyl ether and water
3. customThe layers were separated
4. washthe aqueous phase was washed with methyl t-butyl ether
5. extractionextracted with methyl t-butyl ether
6. washThe combined organic layers were washed with brine
7. dry with materialdried over anhydrous sodium sulfate
8. concentrationThe mixture was concentrated in vacuo
9. dissolutionthe residue was dissolved in diethyl ether (20 mL)
10. additionThe diethyl ether solution was treated with 3M hydrogen chloride in diethyl ether (10 mL)
11. concentrationthe mixture concentrated in vacuo
12. customThe residue was triturated with diethyl ether and hexanes which

ORD record

ord-8e03e2f29d534e388c2d657a81d5a7fc

Source dataset

uspto-grants-2010_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07741327B2