Water → N-(Benzyloxycarbonyl)-L-aspartyl-L-phenylalanine methyl ester

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Reaction Steps

To 24.9 g (0.1 mole) of N-benzyloxycarbonyl-L-aspartic acid anhydride in 100.4 g of acetic acid were added 21.6 g (0.1 mole) of L-phenylalanine methyl ester hydrochloride and 7.6 g (0.055 mole) of potassium carbonate. The reaction was carried out for 3 hours with stirring at 15°-20.C. Thereafter 75.3 g of water was added and the mixture was stirred for one hour at 15°-20.C. The precipitated crystals were filtered, washed and dried to obtain crystals of N-benzyloxycarbonyl-α-L-aspartyl-phenylalanine methyl ester. Analysis of HPLC revealed that the crystals had an α-isomer:β-isomer ratio of 99.6:0.4. The yield of the α-isomer was 28.6 g. In the filtrate, 7.2 g of the α-isomer and 6.2 g of the β-isomer were present.

Provenance & Evidence