tetraethyl 3,4,5-pyridazinetetracarboxylate

3-甲基-2-氯-喹喔啉

ethyl 3-cyanopyridine-4-carboxylate

2-羧酸乙酯-5-氰基吡啶

3-氰基-2-吡啶羧酸乙酯