N-Octyl bicycloheptene dicarboximide113-48-430 % similar exo-5,6-Dehydronorcantharidin6118-51-030 % similar Dicyclopentadiene77-73-630 % similar 3-Oxabicyclo[3.2.0]hept-6-ene-2,4-dione10374-07-930 % similar 3-Oxabicyclo(3.1.0)hexane-2,4-dione5617-74-330 % similar