Brc1c(Br)c(Br)c(Br)c(Br)c1OC(=O)Oc2c(Br)cc(cc2Br)C(C)(C)c3cc(Br)c(OC(=O)Oc4c(Br)c(Br)c(Br)c(Br)c4Br)c(Br)c3