1,3-cyclopentanedione, 2-methyl-2-(2-propenyl)- 2-allyl-2-methylcyclopentane-1,3-dione 26828-48-8 InChI=1/C9H12O2/c1-3-6-9(2)7(10)4-5-8(9)11/h3H,1,4-6H2,2H