(3S)-5-methoxy-3-[((4S,5S)-5-{[(3S)-5-methoxy-1,3-dimethyl-2-oxo-1,3-dihydro-2H-indol-3-yl]methyl}-2,2-dimethyl-1,3-dioxolan-4-yl)methyl]-1,3-dimethyl-1,3-dihydro-2H-indol-2-one