4-Hydroxyphenylpyruvic Acid → (2R)-2-hydroxy-3-(4-hydroxyphenyl)propanoic acid

Temperatur

-20 °C

To a solution of 4-hydroxyphenylpyruvic acid 9.01 g (50.0 mmol) in tetrahydrofuran 120 ml, triethylamine 7.0 ml (50.0 mmol) was added and the mixture was stirred at −20° C. for 0.5 hr. A solution of (−)-B-chlorodiisopinocamphenylborane in 60% hexane 41.2 ml (70.0 mmol) was added to the reaction mixture dropwisely and the mixture was warmed to room temperature and stirred for 6 hrs. 1N sodium hydroxide solution 200 ml was added to the reaction mixture and the mixture was washed with ethyl ether 200 ml. 3N hydrochloride aq. 80 ml was added to the aqueous phase and the mixture was extracted with ethyl acetate 200 ml. The organic phase was washed with brine 200 ml and dried over magnesium sulfate and filtered. The filtrate was concentrated in vacuo and n-hexane:ethyl acetate=60:40 50 ml was added to the residue and the precipitate was corrected by filtration to obtain (R)-2-hydroxy-3-(4-hydroxyphenyl)propanoic acid 5.53 g (yield 61%).

1. temperaturethe mixture was warmed to room temperature
2. stirringstirred for 6 hrs
3. washthe mixture was washed with ethyl ether 200 ml
4. addition3N hydrochloride aq. 80 ml was added to the aqueous phase
5. extractionthe mixture was extracted with ethyl acetate 200 ml
6. washThe organic phase was washed with brine 200 ml
7. dry with materialdried over magnesium sulfate
8. filtrationfiltered
9. concentrationThe filtrate was concentrated in vacuo and n-hexane
10. additionethyl acetate=60:40 50 ml was added to the residue
11. filtrationthe precipitate was corrected by filtration

ORD-Eintrag

ord-c5a7f19d787447a7870bd48aca9ecc11

Quelldatensatz

uspto-grants-2015_05

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US09040531B2