(S)-N-[Bis-(4-methoxy-phenyl)-methyl]-2-[(2R,3R)-2-[(R)-2-(tert-butoxycarbonyl-methyl-amino)-4-methyl-pentanoylamino]-3-(tert-butyl-dimethyl-silanyloxy)-3-(3-chloro-4-hydroxy-phenyl)-propionylamino]-succinamic acid