(2S,3S)-2-(3-Benzyl-ureido)-3-methyl-pentanoic acid [(S)-1-hydroxymethyl-2-(1H-indol-3-yl)-ethyl]-amide

(2S,3S)-2-(3-Benzyl-thioureido)-3-methyl-pentanoic acid [(S)-1-hydroxymethyl-2-(1H-indol-3-yl)-ethyl]-amide

(2S,3S)-3-Methyl-2-[3-(2-trifluoromethyl-phenyl)-ureido]-pentanoic acid [(S)-1-hydroxymethyl-2-(1H-indol-3-yl)-ethyl]-amide

(2S,3S)-3-Methyl-2-(naphthalene-2-sulfonylamino)-pentanoic acid [(S)-1-hydroxymethyl-2-(1H-indol-3-yl)-ethyl]-amide