.alpha.-(2-Hydroxyethyl)acetoacetic acid .gamma.-lactone .alpha.-Acetobutyrolactone .alpha.-Acetyl-.gamma.-butyrolactone .alpha.-Acetyl-.gamma.-hydroxybutyric acid .gamma.-lactone .alpha.-Acetylbutyrolactone 2(3H)-Furanone, 3-acetyldihydro- 2-Acetyl-.gamma.-butyrolactone 2-Acetyl-4-hydroxybutyric acid .gamma.-lactone 2-Acetylbutyrolactone 2-Oxo-3-acetyltetrahydrofuran 3-Acetyl-2(3H)-4,5-dihydrofuranone 3-Acetyltetrahydro-2-furanone 517-23-7 NSC2019