Acetyl chloride → (2S,3R)-2-bromo-3-acetoxy-butyryl chloride

Temperature

5 °C

Acetyl chloride (6.82 g, 86.88 mmole) was added dropwise to (2S, 3R)-2-bromo-3-hydroxybutyric acid (neat) with stirring. The reaction mixture was cooled in a bath at 5° C. as exotherm began. After completion of addition, the cooling bath was removed. After 45 minutes the mixture was heated at 45°-50° C. for 1.5 hours. Heating was discontinued and 10 mL toluene was added. The mixture was cooled in an ice bath and oxalyl chloride (11.4 80 g, 90.44 mmole) was added dropwise. After completion of addition, the mixture was allowed to warm to room temperature then heated at reflux for 30 minutes. Toluene and excess of reagents were removed by fractional distillation. The residue was subjected to bulb-to-bulb distillation at 80°-90° C. under high vacuum (1 mm/Hg) to yield the title compound.

1. additionAfter completion of addition
2. customthe cooling bath was removed
3. temperatureAfter 45 minutes the mixture was heated at 45°-50° C. for 1.5 hours
4. temperatureHeating
5. addition10 mL toluene was added
6. temperatureThe mixture was cooled in an ice bath
7. additionAfter completion of addition
8. temperatureto warm to room temperature
9. temperaturethen heated
10. temperatureat reflux for 30 minutes
11. customToluene and excess of reagents were removed by fractional distillation
12. distillationThe residue was subjected to bulb-to-bulb distillation at 80°-90° C. under high vacuum (1 mm/Hg)

ORD record

ord-931755202c4644a48c05318ec71bd5a7

Source dataset

uspto-grants-1992_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05089609