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

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

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%).

Herkunft & Nachweise