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

(3S)-3-Amino-1-chloro-4-phenyl-2-butanone hydrochloride (2.0 g) was dissolved in water (34 ml). A solution (50 ml) of methyl chloroformate (0.858 ml) in toluene was added to the obtained solution. Further, an aqueous solution (15 ml) of sodium hydrogencarbonate (1.44 g) was added dropwise to the obtained mixture. They were stirred at room temperature for 1 hour to conduct the reaction. After the extraction with toluene twice and with ethyl acetate twice, the organic layers were combined together. The solvents were evaporated under reduced pressure. n-Hexane and 2-propanol were added to the residue. The obtained mixture was heated to 50° C. to obtain a homogeneous solution, which was cooled to 10° C. to form crystals. The crystals were taken by the filtration, 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 reaction
2. extractionAfter the extraction with toluene twice
3. customThe solvents were evaporated under reduced pressure
4. additionn-Hexane and 2-propanol were added to the residue
5. temperatureThe obtained mixture was heated to 50° C.
6. customto obtain a homogeneous solution, which
7. temperaturewas cooled to 10° C.
8. customto form crystals
9. filtrationThe crystals were taken by the filtration
10. washwashed with cold 2-propanol (6 ml)
11. customdried

ORD record

ord-968d060ef52d47d1948625b6ef402b3a

Source dataset

uspto-grants-2003_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06570039B2