O H--C-CHCHCH-C-H CH2-C-CHo-C-CH 戊二醛 2,4-戊二酮(乙酰丙酮 pentanedial 2, 4-pentanedione CH O O 3-甲基环己酮 1,4-环己二酮 3-methylcyclohexanone 1, 4-cyclohexanedioneH C O CH2 CH2 CH2 C O H CH3 C O CH2 C O CH3 戊二醛 2,4-戊二酮(乙酰丙酮) pentanedial 2,4-pentanedione CH3 O O O 3-甲基环己酮 1,4-环己二酮 3-methylcyclohexanone 1,4-cyclohexanedione