5-羟基-6-甲基-3,4-吡啶二甲酸

methyl 2-chloro-3-cyano-6-methylpyridine-4-carboxylate

5-甲氧基-6-甲基-3,4-吡啶二甲醇

ethyl 5-cyano-2-methyl-3-nitro-6-oxo-1H-pyridine-4-carboxylate

5-amino-6-methylpyridine-3,4-dicarboxylic acid