tert-butyl 3-oxo-1-phenyltetrahydro-1H-oxazolo[3,4-a]pyrazine-7(3H)-carboxylate

L-苯丙氨酸

二碳酸二叔丁酯

2-formylpiperazine-1,4-dicarboxylic acid di-tert-butyl ester

2-(羟甲基)-1,4-哌嗪二羧酸二叔丁酯