三氟乙酸 、
((11S,14S)-6,11-bis((tert-butoxycarbonyl)amino)-14-(4-hydroxybenzyl)-2,2-dimethyl-4,12-dioxo-3,13-dioxa-5,7-diazapentadec-5-en-15-oyl)-L-leucyl-L-prolyl-L-threonine 以93%的产率得到(S)-2-Amino-5-guanidino-pentanoic acid (S)-1-{(S)-1-[(S)-2-((1S,2R)-1-carboxy-2-hydroxy-propylcarbamoyl)-pyrrolidine-1-carbonyl]-3-methyl-butylcarbamoyl}-2-(4-hydroxy-phenyl)-ethyl ester; compound with trifluoro-acetic acid