2,5-dimethyl-hexa-2t,4t-dienedinitrile

2,5-dimethyl-hexa-2c,4t-dienedioic acid

2,5-dihydroxy-2,5-dimethyl-adipic acid

2,5-己二酮

1,5-dimethyl-3-oxabicyclo[3.2.0]hept-6-ene-2,4-dione