二碳酸二叔丁酯

(S)-4-苯甲基-2-哌嗪乙醇

1-Benzyl-3(S)-cyclohexyloxycarbonylmethylpiperazine-2,5-dione

N-苄基甘氨酸乙酯

benzyl (S)-2-(4-benzyl-3,6-dioxopiperazin-2-yl)acetate