methyl 4-((1R,2S)-2-(4-((1R,2S)-2-aminocyclobutane-1-carboxamido)butanamido)cyclobutane-1-carboxamido)butanoate 、
在
N,N-二异丙基乙胺 、
Methanaminium,N-[(dimethylamino)(3H-1,2,3-triazolo[4,5-b]pyridin-3-yloxy)methylene]-N-methyl-, hexafluorophosphate(1-) 作用下,
以
二氯甲烷 、
N,N-二甲基甲酰胺 为溶剂,
以62%的产率得到methyl 4-[[(1R,2S)-2-[4-[[(1R,2S)-2-[4-[[(1R,2S)-2-[4-[[(1R,2S)-2-(phenylmethoxycarbonylamino)cyclobutanecarbonyl]amino]butanoylamino]cyclobutanecarbonyl]amino]butanoylamino]cyclobutanecarbonyl]amino]butanoylamino]cyclobutanecarbonyl]amino]butanoate