Toluene → methyl (S)-(1-benzyl-3-chloro-2-oxo-propyl)carbamate

Temperature

50 °C

(3S)-3-amino-1-chloro-4-phenyl-2-butanone hydrochloride (2.0 mg) was dissolved in water (34 ml), and a toluene solution (50 ml) of methyl chloroformate (0.858 ml) was added thereto. An aqueous solution (15 ml) of sodium hydrogencarbonate (1.44 g) was further added dropwise thereto while being stirred. The mixture was reacted at room temperature for 1 hour while being stirred, and then extracted twice with toluene and twice with ethyl acetate. The organic layers were combined, and the solvents were distilled off under reduced pressure. To the residue were added n-hexane and 2-propanol. The resulting solution was heated at 50° C. to form a uniform solution. This solution was then cooled to 10° C., and crystals precipitated were collected by filtration. The crystals were washed with cold 2-propanol (6 ml), and then dried to obtain (3S)-3-methoxycarbonylamino-1-chloro-4-phenyl-2-butanone (1.70 g) in a yield of 78%.

1. customThe mixture was reacted at room temperature for 1 hour
2. stirringwhile being stirred
3. extractionextracted twice with toluene and twice with ethyl acetate
4. distillationthe solvents were distilled off under reduced pressure
5. additionTo the residue were added n-hexane and 2-propanol
6. customto form a uniform solution
7. temperatureThis solution was then cooled to 10° C.
8. customcrystals precipitated
9. filtrationwere collected by filtration
10. washThe crystals were washed with cold 2-propanol (6 ml)
11. customdried

ORD record

ord-b9953e43cd4649f28b57dc71383dc855

Source dataset

uspto-grants-2002_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06500985B2