2,5-Heptadien-4-one, 2,6-dimethyl- 2,6-Dimethyl-2,5-heptadien-4-one 504-20-1 Diisobutenyl ketone Diisopropylidene acetone Foron NSC403517 Phoron Phorone WLN: 1Y1&U1V1UY1&1 sym-Diisopropylidene acetone