Methanol → Aspartame

Participants

Reaction Steps

The α-L-aspartyl-L-phenylalanine (20 g, 0.071 mole) is dissolved in the mixture of water (12.2 ml) and methanol (9.5 ml) and concentrated hydrogen chloride (26 ml) is added while stirring for 48 hours at room temperature to obtain as a precipitate the hydrogen chloride salt of α-L-aspartyl-L-phenylalanine methyl ester (20.3 g, 0.055 mole). After filtration, the cake of precipitate is dissolved in 355 ml of water. Then, the mixture is adjusted to a pH of 4.8 with 50% caustic solution (3.8 ml) and kept overnight at 5° C. to obtain a precipitate and separated by filtration. The filtered precipitate is washed with water (13 ml) at 5° C. and dried to obtain α-L-aspartyl-L-phenylalanine methyl ester (12.4 g, 0.042 mole).

Provenance & Evidence