117653-00-6 4,8,9-Metheno-4H-cyclopenta(1,2-a:4,4-a')dipentalene-4,10-dicarboxylic acid, 1,2,3,3b,4a,5,6,7,8,8a,8b,9-dodecahydro-1,5-dioxo-, diethyl ester Dddmcdd Diethyl 1,2,3,3b,4a,5,6,7,8,8a,8b,9-dodecahydro-1,5-dioxo-4,8,9-metheno-4H-cyclopenta(1,2-a:4,3-a')dipentalene-4,10-dicarboxylate Diethyl 1,2,3,3b,4a,5,6,7,8,8a,8b,9-dodecahydro-1,5-dioxo-4,8,9-metheno-4H-cyclopenta(1,2-a:4,4-a')dipentalene-4,10-dicarboxylate