1,4-diethyl-5-methylpyrrole-2,3-dicarboxylic acid

3-氨基-6-氯-5-氰基-2-甲基异烟酸乙酯

5-羟基-6-甲基-3,4-吡啶二甲酸

乙酰丙酮酸

ethyl 3-(ethoxymethylidene)-2,4-dioxopentanoate