2,7-(Epoxypentadeca(1,11,13)trienimino)benzofuro(4,5-e)pyrido(1,2-a)benzimidazole-1,15(2H)-dione, 25-(acetyloxy)-12-bromo-5,6,21,23-tetrahydroxy-27-methoxy-2,4,16,20,22,24,26-heptamethyl-, (2S-(2R*,16Z,18E,20R*,21R*,22S*,23S*,24S*,25R*,26S*,27R*,28E))-