Réaction #11018

Équation de réaction

L-Phenylalanine hydrochloride

sulfuric acid

sodium nitrite

water

→

(2S)-2-hydroxy-3-phenylpropionic acid

Rendement 42.0%

Solvants

diethyl ether

Conditions de réaction

Traitement

1. 1
   Autrethe organic phase was separated
2. 2
   Extraction(extract 1)
3. 3
   workup.ADDITIONFurther, 50 ml of diethyl ether was added to the aqueous phase
4. 4
   workup.STIRRINGafter stirring
5. 5
   Autrethe organic phase was separated
6. 6
   Extraction(extract 2)
7. 7
   ExtractionThe combined extract (95.0 g)

Mode opératoire

L-Phenylalanine hydrochloride (12.2 g, 60.5 mmol) was added to 183 ml of 5% sulfuric acid (sulfuric acid: 96.0 mmol) and the solution was treated with a mixture of 8.35 g (121 mmol) of sodium nitrite and 44.5 g of water at 0° C. for 3 hours. Thereafter, 100 ml of diethyl ether was added to the reaction mixture and, after stirring, the organic phase was separated (extract 1). Further, 50 ml of diethyl ether was added to the aqueous phase and, after stirring, the organic phase was separated (extract 2). The extracts 1 and 2 were combined. The combined extract (95.0 g) contained 4.2 g of (2S)-2-hydroxy-3-phenylpropionic acid (yield 42%, optical purity 92.6% ee). The proton concentration (normality) in the reaction of this comparative example was 1.4 mol/kg, the amount of the protonic acid was 4.0 equivalents (relative to L-phenylalanine), and the reaction temperature was 0° C.

Source