4-甲基-2-氧代四氢-3-呋喃羧酸

ethyl 4-methyl-2-oxooxolane-3-carboxylate

3-ethoxycarbonyl-4-iodomethyl-4,5-dihydrofuran-2(3H)-one

1-ethyl hydrogen 2-methyl-2-(phenylthio)succinate

醋酸