Hydrochloric Acid → (2S)-2-Hydroxy-2,3-dimethylbutanoic acid

To a magnetically stirred solution of (7) (94 g, 0.47 mol) in methanol (450 mL) and water (100 mL), in a 1-L, one-neck, round-bottom flask was added potassium hydroxide pellets (48 g, 0.85 mol, 1.8 equivalents). The reaction was then heated to reflux for 30 minutes. The mixture was cooled to room temperature and concentrated in vacuo to afford a milky suspension. This mixture was diluted with water (100 mL), cooled to 0° C., and acidified with concentrated hydrochloric acid (15 mL) to pH 6. Additional water (100 mL) was added, and the mixture extracted with ethyl acetate (3×400 mL). The combined organics were washed with water (1×600 mL), saturated aqueous chloride solution (1×600 mL), dried over anhydrous magnesium sulfate, and filtered. The filtrate was concentrated in vacuo to afford a pale yellow oil which on drying in vacuo afforded 59 g (94% yield) of (8) as a crystalline solid. The 1H NMR of the product was consistent with the material previously prepared.

1. temperatureThe reaction was then heated
2. temperatureto reflux for 30 minutes
3. concentrationconcentrated in vacuo
4. customto afford a milky suspension
5. temperaturecooled to 0° C.
6. extractionthe mixture extracted with ethyl acetate (3×400 mL)
7. washThe combined organics were washed with water (1×600 mL), saturated aqueous chloride solution (1×600 mL)
8. dry with materialdried over anhydrous magnesium sulfate
9. filtrationfiltered
10. concentrationThe filtrate was concentrated in vacuo
11. customto afford a pale yellow oil which
12. customon drying in vacuo

ORD record

ord-b9059d7ac5f04188914f00a883bf82da

Source dataset

uspto-grants-2002_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06359012B1