2-氧代-5,6-二氢吡啶-1(2H)-羧酸叔丁酯

甲基6-氧代-1,3,4,6-四氢-2H-喹嗪-9-羧酸酯

N-methyl-2-(2-oxopiperidin-1-yl)acetamide

3-ethylpiperidin-2-one

phenyl 2-oxopiperidine-1-carboxylate