A new general approach to double nitration of 6,12-di(hetero)aryl-substituted and 6,12-unsubstituted 5,11-dialkyl-5,11-dihydroindolo[3,2-b]carbazoles by acetyl nitrate has been developed to obtain their 2,8-dinitro and 6,12-dinitro derivatives, respectively. A formation of mono-nitro derivatives (at C-2 or C-6) from the same indolo[3,2-b]carbazoles has also been observed in several cases. Reduc...
