((R)-4-{(R)-1-[(1H-Benzoimidazol-2-yl)-hydroxy-methyl]-3-phenyl-propylcarbamoyl}-4-tert-butoxycarbonylamino-butyl)-carbamic acid tert-butyl ester

((R)-4-tert-Butoxycarbonylamino-4-{(R)-1-[(5-chloro-benzooxazol-2-yl)-hydroxy-methyl]-3-phenyl-propylcarbamoyl}-butyl)-carbamic acid tert-butyl ester

((R)-4-tert-Butoxycarbonylamino-4-{(R)-1-[(5,6-dimethyl-benzooxazol-2-yl)-hydroxy-methyl]-3-phenyl-propylcarbamoyl}-butyl)-carbamic acid tert-butyl ester

((R)-4-tert-Butoxycarbonylamino-6-{(R)-1-[(5,6-dimethyl-benzooxazol-2-yl)-hydroxy-methyl]-3-phenyl-propylamino}-5-hydroxy-hexyl)-carbamic acid tert-butyl ester