tert-butyl (S)-2-[(S)-2-[2-[[2-(3-benzyl-ureido)-thiazole-4-carbonyl]-amino]-acetylamino]-3-tert-butoxycarbonyl-propionylamino]-3-methyl-butyrate 生成 (S)-2-[(S)-2-[2-[[2-(3-benzyl-ureido)-thiazol-4-carbonyl]-amino]-acetylamino]-3-tert-butoxycarbonyl-propionylamino]-3-methyl-butyric acid acetate/trifluoroacetate