[N:1]1[C:10]2[NH:9][CH2:8][CH2:7][CH2:6][C:5]=2[CH:4]=[CH:3][C:2]=1[CH2:11][CH2:12][CH2:13][CH2:14][C:15]([NH:17][C@H:18]([C:25]1[CH:26]=[N:27][C:28]2[C:33]([CH:34]=1)=[CH:32][CH:31]=[CH:30][CH:29]=2)[CH2:19][C:20]([O:22]CC)=[O:21])=[O:16].[Li+].[OH-].Cl>CCO>[N:27]1[C:28]2[C:33](=[CH:32][CH:31]=[CH:30][CH:29]=2)[CH:34]=[C:25]([C@@H:18]([NH:17][C:15](=[O:16])[CH2:14][CH2:13][CH2:12][CH2:11][C:2]2[CH:3]=[CH:4][C:5]3[CH2:6][CH2:7][CH2:8][NH:9][C:10]=3[N:1]=2)[CH2:19][C:20]([OH:22])=[O:21])[CH:26]=1Ester 5-8 (145 mg, 0.320 mmol) was dissolved in 1 mL EtOH and treated with 1N LiOH (352 mL, 0.35 mmol) and stirred at room temperature overnight. The reaction solution was neutralized with 1N HCl (352 mL), evaporated, and purified by chromatography on silica gel (60% 20:1:1 EtOH/NH4OH/H2O-40% EtOAc) to afford 5-9 as a white solid.
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