3-acetyl-3,5,10,12-tetrahydroxy-6,11-dioxo-1,2,3,4,6,11-hexahydrotetracen-1-yl 3-amino-2,3,6-trideoxy-4-O-{3-hydroxy-1-[(1-hydroxypropan-2-yl)oxy]butyl}hexopyranoside