Reaktion #415502

Reaktionsgleichung

L-phenylalanine methyl ester hydrochloride

ethyl acetate

sodium bicarbonate

→

L-phenylalanine methyl ester

Lösungsmittel

water

Reaktionsbedingungen

Aufarbeitung

1. 1
   TrocknenThe ethyl acetate layer is dried over anhydrous sodium sulfate
2. 2
   Einengenconcentrated to dryness under reduced pressure

Vorschrift

A suspension consisting of 10.8 g. of L-phenylalanine methyl ester hydrochloride, 200 ml. of ethyl acetate and 100 ml. of water is neutralized by the addition of 4.6 g. of sodium bicarbonate. The ethyl acetate layer is dried over anhydrous sodium sulfate, then concentrated to dryness under reduced pressure. The L-phenylalanine methyl ester thus obtained is dissolved in 100 ml. of ethyl acetate and 4.9 g. of L-aspartic acid anhydride hydrobromide is added at -50°C. with stirring. Stirring is continued for about 40 minutes, at the end of which time the reaction mixture is extracted with water. The aqueous layer is separated and the pH adjusted to 4.8 -5.0 by the addition of aqueous sodium carbonate. The aqueous solution is then extracted several times at 50°C. with n-butyl alcohol, which has been equilibrated with an aqueous sodium chloride solution, prepared by dissolution of 11.68 g. of sodium chloride in 1300 ml. of water. The alcohol extracts are combined, then concentrated to dryness under reduced pressure to afford the crude product. Recrystallization of that material from water affords L-α-aspartyl-L-phenylalanine methyl ester.

Quelle