Diethyl 2-<i>tert</i>-butyl-6,9-dibromo-4,11-dioxo-5,10-dihydro-<i>cis</i>-1<i>H</i>,3<i>H</i>,4<i>H</i>,11<i>H</i>-2-azo-3a,4a,10a,11a-tetraazabenz[<i>f</i>]indeno[2,1,7-<i>ija</i>]azulene-11b,11c-dicarboxylate
Acta crystallographica. Section E