72379-59-0 Benzamide, N-(16,17,22,23-tetrahydro-17,22-dioxo-5,10,15,24-tetrakis(sulfooxy)naphth(2',3':6,7)indolo(2,3-c)dinaphtho(2,3-a:2',3'-i)carbazol-18-yl)-, tetrapotassium salt