[Br:1][C:2]1[CH:28]=[CH:27][C:5]([CH2:6][N:7]2[C:15]3[C:10](=[CH:11][C:12]([O:16][CH3:17])=[CH:13][CH:14]=3)[C:9]([CH:18]([CH3:25])[CH2:19][C:20]([O:22]CC)=[O:21])=[C:8]2[CH3:26])=[CH:4][CH:3]=1.[OH-].[K+].O>CCO>[Br:1][C:2]1[CH:28]=[CH:27][C:5]([CH2:6][N:7]2[C:15]3[C:10](=[CH:11][C:12]([O:16][CH3:17])=[CH:13][CH:14]=3)[C:9]([CH:18]([CH3:25])[CH2:19][C:20]([OH:22])=[O:21])=[C:8]2[CH3:26])=[CH:4][CH:3]=1To a suspension of the ester from Step 4 (5.13 g, 11.5 mmol) in 50 mL of EtOH was added 8N KOH (5 mL, 40 mmol) and 5 mL water. The mixture was heated to 60° C. for 1 h, then cooled and concentrated. The residue was partitioned between 1M HCl and EtOAc. The organic phase was washed with brine, dried over MgSO4, filtered and evaporated. Crystallization from CH2Cl2/ hexanes gave 3.59 g of the title compound.
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