1,4-ethanobenzocyclooctene-1(4H)-carboxylic acid, 5,6,7,8,9,10-hexahydro-11,12-dioxo-, methyl ester InChI=1/C16H18O4/c1-20-15(19)16-9-8-11(13(17)14(16)18)10-6-4-2-3-5-7-12(10)16/h8-9,11H,2-7H2,1H methyl 11,12-dioxo-5,6,7,8,9,10-hexahydro-1,4-ethanobenzo[8]annulene-1(4H)-carboxylate