2H-Pyran-2-one, tetrahydro- 5-Valerolactone 542-28-9 AI3-25024 EINECS 208-807-1 NSC 6247 Penta-1,5-lactone Pentanoic acid, 5-hydroxy-, delta-lactone TETRAHYDRO-2H-PYRAN-2-ONE Tetrahydro-2-pyranone Valeric acid, delta-hydroxy-, delta-lactone delta-Valerolactone delta-Valeryllactone