[O:1]=[S:2]1(=[O:20])[CH2:6][CH2:5][CH2:4][N:3]1[C:7]1[CH:12]=[CH:11][C:10]([CH:13]([O:18][CH3:19])[C:14]([O:16]C)=[O:15])=[CH:9][CH:8]=1.[OH-].[Na+]>CO>[O:1]=[S:2]1(=[O:20])[CH2:6][CH2:5][CH2:4][N:3]1[C:7]1[CH:8]=[CH:9][C:10]([CH:13]([O:18][CH3:19])[C:14]([OH:16])=[O:15])=[CH:11][CH:12]=1To a solution of methyl 2-(4-(1,1-dioxidoisothiazolidin-2-yl)phenyl)-2-methoxyacetate (0.48 g, 1.6 mmol) in MeOH (21 mL) was added 1 M NaOH (7 mL, 7 mmol) slowly. After stirring at room temperature for 23 hrs, the volatiles were removed in vacuo and the residue was dissolved in H2O. EtOAc was added to the aqueous solution and saturated aqueous NH4Cl and 1 M HCl were added slowly until the pH ˜3. The mixture was extracted with EtOAc then the aqueous layer was acidified to pH 1 and extracted with EtOAc again. The combined organics were washed with H2O and brine, dried over Na2SO4 and concentrated in vacuo to give 2-(4-(1,1-dioxidoisothiazolidin-2-yl)phenyl)-2-methoxyacetic acid as a yellow foam (0.378 g, 82% yield). The product was used in the next synthetic step without further purification.
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