gamma-butyrolactone1,2-butanolide1,4-Butanolide1,4-Lactone4-Butyrolactone4-Deoxytetronic acid4-Hydroxybutyric acid lactoneButyrolactoneGAMMA-BUTYROLACTONEdihydro-2(3H)-furanonegamma-butanolactonegamma-butyrolactonegamma-hydroxybutyric acid lactonegamma-hydroxybutyrolactonetetrahydrofuran-2-one