| 2-Butenoic acid,4-hydroxy-,.gamma.-lactone |
| Crotonic acid,4-hydroxy-,.gamma.-lactone |
| 4-H |
| 5H-Furan-2-one |
| 2(5H)-Furanone |
| 2-Butenoic acid, 4-hydroxy-, .gamma.-lactone |
| 2-Butenoic acid .gamma.-lactone |
| .delta.,.alpha.,.beta.-Butenolide |
| 2-Buten-4-olide |
| .gamma.-Crotolactone |
| .alpha.,.beta.-Crotonolactone |
| Crotonic acid, 4-hydroxy-, .gamma.-lactone |
| .gamma.-Crotonolactone |
| 4-Hydroxy-2-butenoic acid lactone |
| 4-Hydroxy-2-butenoic acid .gamma.-lactone |
| .gamma.-Hydroxycrotonic acid lactone |
| Isocrotonolactone |
| 2-Oxo-2,5-dihydrofuran |
| 2-butenoic acid gamma-lactone |
| 4-hydroxy-2-butenoic aci gamma-lactone |
| 4-hydroxy-2-butenoic acid gamma-lactone |
| alpha,beta-crotonolactone |
| 4-hydroxy-crotonic aci gamma-lactone |
| delta,alpha,beta-butenolide |
| gamma-crotolactone |
| gamma-crotonolactone |
| gamma-hydroxycrotonic acid lactone |
| 2-Buten-1,4-olide |
| γ-Crotonolactone |
