6-硝基-4-氧代-4H-1-苯并吡喃-2-羧酸乙酯

3-乙基-1H-吡唑-5-羧酸乙酯

ethyl 6-methoxy-3-methyl-1H-indole-2-carboxylate

2-(4-甲氧基苯基)-丙二酸二乙酯

4-ethoxy-2,4-dioxobutanoate