4,12c-Ethano-12cH-anthra[9,1-bc]oxepin-7-carboxylicacid, 2,3,4,4a,5,6,7,7a,8,9,12,12b-dodecahydro-3-methyl-9,12-dioxo-, (3a,4a,4aa,7a,7aa,12bb,12ca)-(?à)-