N-tert-butoxycarbonyl-L-leucyl-O-benzyl-L-seryl-L-leucine benzyl ester

(R)-4-((S)-3-Benzyloxy-2-{(R)-2-[(4aR,6S,7R,8R,8aS)-6-benzyloxy-7-(2-benzyloxy-acetylamino)-2-phenyl-hexahydro-pyrano[3,2-d][1,3]dioxin-8-yloxy]-propionylamino}-propionylamino)-4-carbamoyl-butyric acid benzyl ester

O-benzyl-L-seryl-D-isoglutamine benzyl ester

(S)-2-((S)-2-Amino-3-benzyloxy-propionylamino)-4-methyl-pentanoic acid benzyl ester

(S)-2-((S)-2-Amino-3-benzyloxy-propionylamino)-3-benzyloxy-propionic acid benzyl ester