(S)-methyl 1-(2-amino-3-(4-nitrophenyl)propyl)cyclopropanecarboxylate 、
2-((5R,7R,10S)-10-((S)-sec-butyl)-7-isopropyl-12-((R)-1-methylpiperidin-2-yl)-3,9,12-trioxo-8-propyl-4-oxa-2,8,11-triazadodecan-5-yl)thiazole-4-carboxylic acid 以to yield methyl 1-((S)-2-(2-((5R,7R,10S)-10-((S)-sec-butyl)-7-isopropyl-12-((R)-1-methylpiperidin-2-yl)-3,9,12-trioxo-8-propyl-4-oxa-2,8,11-triazadodecan-5-yl)thiazole-4-carboxamido)-3-(4-nitrophenyl)propyl)-cyclopropanecarboxylate (Ib-4)的产率得到methyl 1-((S)-2-(2-((5R,7R,10S)-10-((S)-sec-butyl)-7-isopropyl-12-((R)-1-methylpiperidin-2-yl)-3,9,12-trioxo-8-propyl-4-oxa-2,8,11-triazadodecan-5-yl)thiazole-4-carboxamido)-3-(4-nitrophenyl)propyl)-cyclopropanecarboxylate