2-methylamino-benzoic acid 8-(2-{[1-(2-{2-[2-(9H-fluoren-9-ylmethoxycarbonylamino)-4-methylsulfanyl-butyrylamino]-acetylamino}-4-methyl-pentanoyl)-pyrrolidine-2-carbonyl]-amino}-2-methoxycarbonyl-ethylsulfanyl)-2,6-dimethyl-octa-2,6-dienyl ester