2-methyl-1-oxidoquinolin-1-ium-4-carboxylic acid

methyl 1-methyl-2-oxo-1,2-dihydroquinoline-4-carboxylate

1-甲基-2-氧代-1,2-二氢喹啉-4-甲醛

1,4-二甲基喹啉酮

2-甲基喹啉-4-羧酸