.DELTA.1-Angelica lactone .alpha.,.beta.-Angelica lactone .beta.(.alpha.,.beta. or .delta.1)-Angelica lactone .beta.-Angelica lactone .delta.(sup1)-Angelica lactone .gamma.-Methyl-.DELTA..alpha.,.beta.-butenolide .gamma.-Methyl-.alpha.,.beta.-crotonolactone 2(5H)-Furanone, 5-methyl- 2-Penten-4-olide 2-Pentenoic acid, 4-hydroxy-, .gamma.-lactone 4-Hydroxy-2-pentenoic acid .gamma.-lactone 4-Hydroxypent-2-enoic acid lactone 5-Methyl-2(5H)-furanone 591-11-7 NSC655 WLN: T5OV EHJ E1