| 摘要 |
<p>A process is described for the preparation of N- alpha -L-aspartyl-L-phenylalanine methyl ester (Aspartame). According to the process, a completely protected L-aspartic acid derivative is reacted with L-phenylalanine methyl ester in the presence of a condensing agent, the condensing agent having been obtained by reacting a nitrogen-containing heterocyclic compound with an organic or inorganic acid chloride. The protective groups are then removed by catalytic transfer hydrogenation using ammonium formate, cyclohexane or cyclohexadiene as hydrogen donor, and the resulting Aspartame is eventually obtained and purified by methods known per se. The process according to the invention gives the alpha isomer of Aspartame in high yields and in high purity, and the formation of undesired beta isomers is avoided.</p> |
