3-[({6-[(2-{4-[(3-amino-2,3,6-trideoxyhexopyranosyl)oxy]-2,5,12-trihydroxy-7-methoxy-6,11-dioxo-1,2,3,4,6,11-hexahydrotetracen-2-yl}-2-oxoethyl)sulfanyl]hexyl}sulfanyl)acetyl]-3,5,12-trihydroxy-10-methoxy-6,11-dioxo-1,2,3,4,6,11-hexahydrotetracen-1-yl 3-a