[Br:1][C:2]1[CH:28]=[C:27]([CH:29]([CH3:31])[CH3:30])[CH:26]=[CH:25][C:3]=1[O:4][CH:5]([CH3:24])[C:6]([NH:8][C:9]1[CH:14]=[CH:13][C:12]([CH:15]([O:22][CH3:23])[CH2:16][C:17]([O:19]CC)=[O:18])=[CH:11][CH:10]=1)=[O:7].O.Cl>C(#N)C.[OH-].[Na+]>[Br:1][C:2]1[CH:28]=[C:27]([CH:29]([CH3:31])[CH3:30])[CH:26]=[CH:25][C:3]=1[O:4][CH:5]([CH3:24])[C:6]([NH:8][C:9]1[CH:10]=[CH:11][C:12]([CH:15]([O:22][CH3:23])[CH2:16][C:17]([OH:19])=[O:18])=[CH:13][CH:14]=1)=[O:7]A solution of 331 mg of ethyl 3-{4-[2-(2-bromo-4-isopropylphenoxy)propionylamino]-phenyl}-3-methoxypropionate in 7 ml of acetonitrile and 7 ml of 1 N NaOH (aq) was stirred at room temperature for 20 h. The reaction mixture was admixed with water and adjusted to pH=1 with 1 N HCl (aq) and then extracted with ethyl acetate. The organic phase was dried over MgSO4, filtered and concentrated under high vacuum. The crude mixture was purified by means of preparative HPLC (Merck Hibar Purospher Star RP-18e 10 μm 25×250 mm; A: H2O+0.05% TFA; B: ACN+0.05% TFA; flow rate: 50 ml/min; in 10 minutes 10% B→80% B; in 5 minutes 80% B→90% B). This gave 152 mg of 3-{4-[2-(2-bromo-4-isopropylphenoxy)propionylamino]phenyl}-3-methoxypropionic acid in 49% yield over the two stages.
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