To 2,4-dichlorophenoxyacetic acid (110.6 mg, 0.5 mmol), 2-(3-amino-benzenesulfonyl)-ethanol (151.0 mg, 0.75 mmol), N-(3-dimethylaminopropyl)-N′-ethyl carbodiimide HCl (EDC) (143.8 mg, 0.75 mmol) and 1-hydroxybenzotriazole (HOBt) (102.1 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 10% HCl. The organic phase was washed with brine, dried (MgSO4 anh), and concentrated. The residue was purified by preparative (CH2CH2:MeOH=30:1) to give 2-(2,4-dichloro-phenoxy)-N-[3-(2-hydroxy-ethanesulfonyl)-phenyl]-acetamide as a yell foam (21.5 mg, 10.6% yield).
