The general procedure for the synthesis of p-iodophenoxyacetic acid from ethyl (4-iodophenoxy)acetate was as follows: ethyl (4-iodophenoxy)acetate (1.53 g, 5.0 mmol) was mixed with lithium hydroxide monohydrate (258 mg, 6.1 mmol) in a 1:1 mixture of tetrahydrofuran (THF) and water (12 mL) and stirred for 5 min at room temperature. Upon completion of the reaction, the reaction was quenched with 1N hydrochloric acid (HCl) solution, followed by removal of the organic solvent by distillation under reduced pressure. The crude product was extracted with ethyl acetate, washed sequentially with saturated aqueous sodium chloride (NaCl) solution and dried with anhydrous magnesium sulfate (MgSO4), and finally concentrated to give p-iodophenoxyacetic acid (1.36 g, 4.9 mmol, 98% yield) as a white solid. The product was confirmed by nuclear magnetic resonance hydrogen spectrum (1H NMR, 400 MHz, CD3OD): δ 7.48 (d, J = 8.6 Hz, 2H), 6.66 (d, J = 8.6 Hz, 2H), 4.54 (s, 2H); nuclear magnetic resonance carbon spectrum (13C NMR, 100 MHz, CD3OD): δ 172.3, 159.4, 139.4 , 118.1, 84.1, 65.8; mass spectrum (ESI) m/z 276 [M-H]-.
