Hydrochloric Acid → tert-Butyl (R)-2-hydroxybutyrate

Temperature

40 °C

tert-Butyl acetoacetate [15] (14.5 g, 90 mmol) and methanol (30 mL) were mixed and deoxygenated with flowing nitrogen for 5 minutes in a septum covered Parr shaker bottle. The catalyst prepared as described above (36 mg, 0.02 mmol) was added along with 2N HCl (0.041 mL, 0.082 mmol). The mixture was transferred to a standard Parr shaker apparatus and flushed by evacuating and refilling with nitrogen and then hydrogen several times. The apparatus was heated at 40° C. with shaking under 50 psi of hydrogen. After 20 min the reaction became a homogeneous clear yellow solution which took up hydrogen for approximately eight hours. At this time the reaction was complete and the mixture was cooled and diluted with hexane (30 mL) to precipitate the catalyst, which was filtered away. The filtrate was concentrated to give tert-butyl 3(R)-hydroxybutyrate [16] (14.5 g, 97%).

1. customdeoxygenated with flowing nitrogen for 5 minutes in a septum
2. customThe catalyst prepared
3. customflushed
4. customby evacuating
5. customfor approximately eight hours
6. temperaturethe mixture was cooled
7. additiondiluted with hexane (30 mL)
8. customto precipitate the catalyst, which
9. filtrationwas filtered away
10. concentrationThe filtrate was concentrated

ORD record

ord-54223e7338944af4b03afbd512e75f67

Source dataset

uspto-grants-1996_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05508435