methyl 7-acetyloxy-4-[5-[4-acetyloxy-6-methyl-5-(6-methyl-5-oxo-oxan-2 -yl)oxy-oxan-2-yl]oxy-4-dimethylamino-6-methyl-oxan-2-yl]oxy-2-ethyl-2 ,5,9-trihydroxy-6,11-dioxo-3,4-dihydro-1H-tetracene-1-carboxylate