.gamma.-Heptalactone .gamma.-Heptanolactone .gamma.-Propiobutyrolactone .gamma.-Propyl-.gamma.-butyrolactone 105-21-5 2(3H)-Furanone, dihydro-5-propyl- 4-Hydroxyheptanoic acid lactone 4-Hydroxyheptanoic acid, .gamma.-lactone NSC46352