3-hydroxy-4-methyl-2H-furan-5-one

Butanoic acid, 4-bromo-2-methyl-3-oxo-, methyl ester

(+/-)-2-chloro-2-methyl-3-oxo-γ-butyrolacton

(R,S)-4-(phenylthio)-2-methylbutanoic acid

2-methyl-4-phenylthio-4-butanolide