3-oxobutanoic acid

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

2-正己基乙酰乙酸甲酯

methyl 5-butyl-2-methyl-4,5-dihydrofuran-3-carboxylate

(2R,3S,5R)-methyl 5-butyl-2-hydroxy-2-methyltetrahydrofuran-3-carboxylate