[O:1]1[C:5]2[CH:6]=[CH:7][CH:8]=[CH:9][C:4]=2[N:3]=[C:2]1[NH:10][C:11]1[CH:16]=[CH:15][C:14]([CH2:17][C:18]([O:20]CC)=[O:19])=[CH:13][C:12]=1[Cl:23].[OH-].[Na+]>C1COCC1>[O:1]1[C:5]2[CH:6]=[CH:7][CH:8]=[CH:9][C:4]=2[N:3]=[C:2]1[NH:10][C:11]1[CH:16]=[CH:15][C:14]([CH2:17][C:18]([OH:20])=[O:19])=[CH:13][C:12]=1[Cl:23]Ethyl (4-(2-benzoxazolyl)amino-3-chlorophenyl)acetate (1.70 g, 5.14 mmol) was dissolved in THF (30 ml). To the resulting solution was added 0.5N NaOH (30 ml, 15.0 mmol) under stirring. The resulting mixture was stirred at room temperature for 20 hours. The mixture was concentrated and the residue was acidified with ice-1N HCl. The crystals thus precipitated were collected by filtration under reduced pressure, washed with water and dried under reduced pressure to give (4-(2-benzoxazolyl)amino-3-chlorophenyl)acetic acid (1.24 g, 80%) as a pale yellow crystalline powder.
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