2-甲氧基-3-甲基环戊-2-烯-1-酮

2-methoxy-5-methyl-cyclopent-2-enone

(2S)-2-methyl-5-oxooxolane-2-carboxylic acid

乙酰丙酸

2-甲基-5-氧代四氢-2-呋喃羧酸