6-ethyl-5-propionyl-2H-pyran-2-one

2H-Pyran-5-carboxylic acid, 6-methyl-2-oxo-, ethyl ester

6-甲基-2-氧代-2H-吡喃-5-羧酸甲酯

2-(1,3-二氧戊环-2-基)乙酸乙酯

[1,2,3]噻二唑-5-羧酸乙酯