Hydrochloric Acid → Methyl 2-amino-3-oxobutanoate hydrochloride

Potassium tert-butylate (17.8 g, 157.9 mmol) was introduced into THF (120 ml), and a solution of N-diphenylmethylideneglycine methyl ester (40 g, 157.9 mmol) in THF (60 ml) was added at −70° C. After the yellowish solution had been stirred for 30 minutes at this temperature, it was added dropwise at −70° C. to a solution of acetyl chloride (12.4 g, 157.9 mmol) in THF (70 ml). After the mixture had been stirred at this temperature for 1.75 hours, 3N HCl (160 ml) was added, and the yellowish suspension was stirred for a further 10 minutes at room temperature. The THF was removed at room temperature on a rotary evaporator, and the remaining aqueous phase was washed 3× with diethyl ether. The aqueous phase was freeze-dried and the residue was extracted by stirring with methanol. The methanolic solution of the product was concentrated on a rotary evaporator at 35° C. Yield: 26.4 g (157.9 mmol, quant., yellowish solid).

1. stirringAfter the mixture had been stirred at this temperature for 1.75 hours
2. stirringthe yellowish suspension was stirred for a further 10 minutes at room temperature
3. customThe THF was removed at room temperature on a rotary evaporator
4. washthe remaining aqueous phase was washed 3× with diethyl ether
5. customThe aqueous phase was freeze-dried
6. extractionthe residue was extracted
7. stirringby stirring with methanol
8. concentrationThe methanolic solution of the product was concentrated on a rotary evaporator at 35° C

ORD record

ord-bf354eab24494ddbb53530cc1ae9aee4

Source dataset

uspto-grants-2004_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06740647B1