12-[3,4-Dihydroxy-6-(hydroxymethyl)-5-methoxyperhydro-2H-pyran-2-yl]-3,9-dibromo-6-methylindolo[2,3-a]3-pyrrolino[3,4-c]carbazole-5,7-dione AIDS-079987 AIDS079987 Indolocarbazole Rebeccamycin analog