2,2,4-Trimethyl-3-hydroxy-3-pentenoic acid .beta. lactone 2-Oxetanone, 3,3-dimethyl-4-(1-methylethylidene)- 2-Oxetanone, 4-isopropylidene-3,3-dimethyl- 3-Hydroxy-2,2,4-trimethyl-3-pentenoic acid, .beta.-lactone 3173-79-3 4-Isopropylidene-3,3-dimethyl-2-oxetanone Dimethylketene dimer NSC74312 WLN: T4VOY DHJ CUY1&1 D1 D1