1,7-Dioxadispiro(4.0.4.2)dodeca-2,8-diene-11,12-dicarboxylic acid, 2,8-bis(4-methylphenyl)-3,9-dibromo-4,10-dioxo-, dimethyl ester, (5-alpha,6-alpha,11-alpha,12-alpha)- 142273-66-3 BRN 5841981