L-proline
(S)-3-(6-chloroimidazo<1,2-b>pyridazin-2-yl)alanine
diphenylmethyl (3S,6S,9aS)-6-[(2S)-2-((2S)-2-((2S)-2-(9H)-fluoren-9-ylmethoxycarbonylamino-4-methylpentanamido)-4-tert-butoxycarbonylpropanamido)-3-methylbutanamido]-5-oxo-octahydro-1H-pyrrolo[1,2-a]azepine-3-carboxylate
diphenylmethyl (3S,6S,9aS)-6-[(2S)-2-((2S)-2-((2S)-2-(2-benzyloxycarbonylaminoacetamido)-4-methylpentanamido)-4-tert-butoxycarbonylpropanamido)-3-methylbutanamido]-5-oxo-octahydro-1H-pyrrolo[1,2-a]azepine-3-carboxylate
diphenylmethyl (3S,6S,9aS)-6-[(2S)-2-((2S)-2-(9H)-fluoren-9-ylmethoxycarbonylamino-4-tert-butoxycarbonylpropanamido)-3-methylbutanamido]-5-oxo-octahydro-1H-pyrrolo[1,2-a]azepine-3-carboxylate