(1s,2s,4r,5r)-8,13-dihydroxy-4-methyl-7,12-dioxo-4,4',5,5',7,12-hexahydro-1h,1'h-spiro[1,4-methanoanthra[2,3-d]oxepine-2,2'-pyrrolo[2,3-b]pyrrol]-5-yl 4-c-acetyl-2,6-dideoxy-