Benzo[1,2-C:4,5-C′]dipyrrole-1,3,5,7(2H,6H)-tetrone2550-73-4100 % similar 2H-1,3-Benzoxazine-2,4(3H)-dione2037-95-834 % similar 6(5H)-Phenanthridinone1015-89-032 % similar