申请人:Mitsui Toatsu Chemicals, Inc.
公开号:US04780561A1
公开(公告)日:1988-10-25
Disclosed herein is a process for preparing .alpha.-L-aspartyl-L-phenylalanine methyl ester or its hydrochloride from 5-benzyl-3,6-dioxo-2-piperazine acetic acid or its methyl ester, prepared without using L-penylalanine methyl ester which involves problems in its stability, as a raw material. Specifically, the process comprises: bringing 5-benzyl-3,6-dioxo-2-piperazine acetic acid in the presence of methanol or 5-benzyl-3,6-dioxo-2-piperazine acetic acid methyl ester in the presence or absence of methanol into contact with hydrochloric acid; isolating the thereby deposited .alpha.-L-aspartyl-L-phenylalanine methyl ester hydrochloride; and neutralizing said hydrochloride with an alkali as required. Preparation processes of 5-benzyl-3,6-dioxo-2-piperazine acetic acid or its methyl ester are also disclosed.
本文披露了一种从5-苄基-3,6-二氧代-2-哌嗪乙酸或其甲酯制备α-L-天冬氨酸基-L-苯丙氨酸甲酯或其盐酸盐的过程,而无需使用L-苯丙氨酸甲酯,因为其稳定性存在问题。具体而言,该过程包括:将5-苄基-3,6-二氧代-2-哌嗪乙酸或其甲酯在甲醇或5-苄基-3,6-二氧代-2-哌嗪乙酸甲酯的存在或缺席下与盐酸接触;分离由此沉淀的α-L-天冬氨酸基-L-苯丙氨酸甲酯盐酸盐;并根据需要用碱中和该盐酸盐。还披露了5-苄基-3,6-二氧代-2-哌嗪乙酸或其甲酯的制备过程。