2-羟基戊二酸二乙酯

7-benzyl-1-oxa-7,10-diazaspiro[4.5]decane-6,9-dione

ethyl 6-oxo-4,5-dihydro-1H-pyridazine-3-carboxylate

高柠檬酸-gamma-内酯

2,5-二羟基-4-甲基-2,5-二氧代-3-呋喃丙酸