{(S)-1-[(Methoxy-methyl-carbamoyl)-methyl]-3-methyl-butyl}-carbamic acid tert-butyl ester

((S)-2-{(S)-2-[(S)-2-Amino-3-(1H-indol-3-yl)-propionylamino]-propionylamino}-3-methyl-butyrylamino)-acetic acid benzyl ester

((S)-2-{(S)-2-[(S)-2-((S)-2-Amino-4-carbamoyl-butyrylamino)-3-(1H-indol-3-yl)-propionylamino]-propionylamino}-3-methyl-butyrylamino)-acetic acid benzyl ester

((S)-2-{(S)-2-[(S)-2-(9H-Fluoren-9-ylmethoxycarbonylamino)-3-(1H-indol-3-yl)-propionylamino]-propionylamino}-3-methyl-butyrylamino)-acetic acid benzyl ester

((S)-2-{(S)-2-[(S)-2-[(S)-4-Carbamoyl-2-(9H-fluoren-9-ylmethoxycarbonylamino)-butyrylamino]-3-(1H-indol-3-yl)-propionylamino]-propionylamino}-3-methyl-butyrylamino)-acetic acid benzyl ester