1-tert-Butyl-3-((S)-2-{4-[(4aS,8aR)-4-(3,4-dimethoxy-phenyl)-1-oxo-4a,5,8,8a-tetrahydro-1H-phthalazin-2-yl]-piperidin-1-yl}-1-methyl-2-oxo-ethyl)-urea