[(1S,2S,4R)-1-Benzyl-4-(carbamoylmethyl-carbamoyl)-2-hydroxy-5-phenyl-pentyl]-carbamic acid tert-butyl ester

{(1S,2S,4R)-1-Benzyl-4-[((S)-carbamoyl-phenyl-methyl)-carbamoyl]-2-hydroxy-5-phenyl-pentyl}-carbamic acid tert-butyl ester

{(1S,2S,4R)-1-Benzyl-4-[((S)-carbamoyl-cyclohexyl-methyl)-carbamoyl]-2-hydroxy-5-phenyl-pentyl}-carbamic acid tert-butyl ester