Sodium hydride → 4-Methyl-3-phenylpentanoic acid

Under a nitrogen atmosphere, sodium hydride (60%, 1.2 g) was added at 0° C. to a tetrahydrofuran solution (30 mL) of tert-butyldiethylphosphonoacetate (4.9 g). After 10 minutes, the temperature of the mixture was naturally returned to room temperature, and the mixture was stirred. After 1 hour, a tetrahydrofuran solution (10 mL) of isobutyrophenone (4.0 g) was added. After stirring for 13 hours, the organic layer was separated by adding water and ethyl acetate thereto. The resulting organic layer was washed with water and brine, and dried over anhydrous magnesium sulfate. After filtering off the drying agent, the mixture was evaporated. 5.48 g among the resulting crude product (6.1 g) was dissolved in methanol (30 mL), a catalytic amount of 10% palladium carbon (250 mg) was added, and the mixture was reacted under pressuring by hydrogen (3.9 kg/cm2). After 1.3 hours, the catalyst was filtered off, and then the filtrate was concentrated. The resulting residue was purified by silica gel column chromatography (hexane:ethyl acetate system). The resulting product (3.0 g) was dissolved in acetone (50 mL) and 5N hydrochloric acid (20 mL), and the mixture was stirred for 3 hours under reflux conditions. The solution was evaporated, to give the title compound as a reddish yellow oil (1.96 g, 58%: 3 steps).

1. customwas naturally returned to room temperature
2. waitAfter 1 hour
3. stirringAfter stirring for 13 hours
4. customthe organic layer was separated
5. additionby adding water and ethyl acetate
6. washThe resulting organic layer was washed with water and brine
7. dry with materialdried over anhydrous magnesium sulfate
8. filtrationAfter filtering off the drying agent
9. customthe mixture was evaporated
10. dissolution5.48 g among the resulting crude product (6.1 g) was dissolved in methanol (30 mL)
11. additiona catalytic amount of 10% palladium carbon (250 mg) was added
12. customthe mixture was reacted under pressuring by hydrogen (3.9 kg/cm2)
13. waitAfter 1.3 hours
14. filtrationthe catalyst was filtered off
15. concentrationthe filtrate was concentrated
16. customThe resulting residue was purified by silica gel column chromatography (hexane:ethyl acetate system)
17. dissolutionThe resulting product (3.0 g) was dissolved in acetone (50 mL)
18. stirring5N hydrochloric acid (20 mL), and the mixture was stirred for 3 hours under reflux conditions
19. customThe solution was evaporated

ORD record

ord-ca325ef4724146e09691dc401dd758e2

Source dataset

uspto-grants-2005_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06906072B1