1-butan-2-yl-5-methylidenecyclopenta-1,3-diene;5-methylene-1-sec-butyl-cyclopenta-1,3-diene;5-methylene-1-sec-butylcyclopenta-1,3-diene;1-butan-2-yl-5-methylidene-cyclopenta-1,3-diene
1-butan-2-yl-5-methylidenecyclopenta-1,3-diene