[Cl:1][C:2]1[C:11]([C:12]2[CH2:16][CH:15]([CH2:17][C:18]3[CH:23]=[CH:22][CH:21]=[CH:20][CH:19]=3)[O:14][N:13]=2)=[C:10]([S:24]([CH3:27])(=[O:26])=[O:25])[CH:9]=[CH:8][C:3]=1[C:4]([O:6]C)=[O:5].[OH-].[Na+]>CO.O>[Cl:1][C:2]1[C:11]([C:12]2[CH2:16][CH:15]([CH2:17][C:18]3[CH:23]=[CH:22][CH:21]=[CH:20][CH:19]=3)[O:14][N:13]=2)=[C:10]([S:24]([CH3:27])(=[O:25])=[O:26])[CH:9]=[CH:8][C:3]=1[C:4]([OH:6])=[O:5]1.02 g (2.5 mmol) of methyl 2-chloro-3-(5-benzylisoxazolin-3-yl)-4-methylsulfonylbenzoate are dissolved in 20 ml of methanol and combined with 0.15 g (3.7 mmol) of sodium hydroxide—dissolved in 10 ml of water—at room temperature. After 16 hours, the methanol is removed by distillation, the residue is diluted with water and, after acidifying to pH 2, the mixture is extracted with dichloromethane. After concentrating in a rotary evaporator, 0.85 g (87% of theory) of 2-chloro-3-(5-benzylisoxazolin-3-yl)4-methylsulfonylbenzoic acid is obtained as a yellowish resin.
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