[Br:1][C:2]1[CH:7]=[CH:6][C:5]([OH:8])=[C:4]([Cl:9])[CH:3]=1.C(=O)([O-])[O-].[K+].[K+].Cl[CH2:17][C:18]([O:20][CH2:21][CH3:22])=[O:19].O>CN(C=O)C>[CH2:21]([O:20][C:18](=[O:19])[CH2:17][O:8][C:5]1[CH:6]=[CH:7][C:2]([Br:1])=[CH:3][C:4]=1[Cl:9])[CH3:22]A mixture of 4-bromo-2-chloro-phenol (2.0 g, 9.64 mmol) and anhydrous potassium carbonate (4.0 g, 28.92 mmol) in dry DMF (30 ml) was heated at 60° C. for 1 h under Ar atmosphere. The mixture was then cooled to room temperature and ethyl chloroacetate (1.24 ml, 11.57 mmol) was added through septum using syringe. The mixture was stirred overnight at room temperature and poured into water with stirring. Stirring continued for 10 min, and then partitioned between ethyl acetate and water. The organic phase washed with brine, dried (anhydrous MgSO4), and concentrated. The residue was purified by silica gel column chromatography (n-Hexane:Ethyl acetate:MeOH=15:3:1) to give (4-Bromo-2-chloro-phenoxy)-acetic acid ethyl ester as a colorless oil (2.98 (2.83) g, >100% yield). To (4-bromo-2-chloro-phenoxy)-acetic acid (132.8 mg, 0.5 mmol), 3-amino-benzamide (102.2 mg, 0.75 mmol), N-(3-dimethylaminopropyl)-N′-ethyl carbodiimide HCl (EDC) (143.8 mg, 0.75 mmol) and 1-hydroxybenzotriazole (HOBt) (101.4 mg, 0.75 mmol) in DMF (5 ml) was added N,N-diisopropylethylamine, redistilled (DIPEA) (0.13 ml, 0.75 mmol). The mixture was stirred overnight, and then partitioned between ethyl acetate and water. The organic phase was washed with brine, dried (MgSO4 anh), and concentrated. The residue was purified by silica gel flash column chromatography (CH2CH2:MeOH=10:1) to give 3-[2-(4-bromo-2-chloro-phenoxy)acetyl-amino]-benzamide as a white solid (181.4 mg, 94.6% yield).
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