(alphaRS,S)-alpha-benzyl-1-t-butoxycarbonyl-gamma-oxo-2-pyrrolidinebutyric acid 、
(S)-α-amino-N-[(1S,2S,4S)-1-(cyclohexylmethyl)-2-hydroxy-4-isopropyl-5-hexenyl]imidazole-4-propionamide 以there were obtained t-butyl (S)-2-[[(S)-α-[[(S)-1-[[(1S,2S,4S)-1-(cyclohexylmethyl)-2-hydroxy-4-isopropyl-5-hexenyl]carbamoyl]-2-imidazol-4-ylethyl]carbamoyl]phenethyl]acetyl]-1-pyrrolidinecarboxylate (less polar isomer) and t-butyl (S)-2-[[(R)-γ-[[(S)-1-[[(1S,2S,4S)-1-(cyclohexylmethyl)-2-hydroxy-4-isopropyl-5-hexenyl]carbamoyl]-2-imidazol-4-ylethyl]carbamoyl]phenethyl]acetyl]-1-pyrrolidinecarboxylate的产率得到t-butyl (S)-2-[[(S)-α-[[(S)-1-[[(1S,2S,4S)-1-(cyclohexylmethyl)-2-hydroxy-4-isopropyl-5-hexenyl]carbamoyl]-2-imidazol-4-ylethyl]carbamoyl]phenethyl]acetyl]-1-pyrrolidinecarboxylate