乙基 1H-吡咯-3-羧酸

diethyl 2-formyl-2-azabutane-1,4-dicarboxylate

ethyl 4-(3-ethoxy-3-oxopropyl)benzoate

2-氮杂丁烷-1,4-二羧酸二乙酯

5-propan-2-yloxolan-2-one