abstract |
This invention relates to a process for manufacturing α-L-aspartyl-L-phenylalanine methyl ester (''α-APM'') by use of 5(S)-benzyl-3,6,-dioxopiperazine-2(S)-acetic acid (''AP-DKP'') or methyl 5(S)-benzyl-3,6,-dioxopiperazine-2(S)-acetate (''MAP-DKP'') or respective 1-acyl derivatives thereof (''1-acyl AP-DKP'' and ''1-acyl MAP-DKP'') and novel intermediates produced therein. |