Ammonium Chloride → 4-Chloro-5-iodobenzene-1,2-diamine

To a solution of 5-chloro-2-nitroaniline (500 mg, 2.90 mmol) in acetic acid (20 ml) was added NIS (650 mg, 2.89 mmol). The resulting solution was stirred overnight at room temperature and then diluted with water (40 ml). The solids were collected by filtration to afford 5-chloro-4-iodo-2-nitroaniline as a brown solid (800 mg, crude). To a solution of 5-chloro-4-iodo-2-nitroaniline (800 mg, crude) in water (4 ml) and ethanol (20 ml) was added Fe powder (600 mg, 10.74 mmol) and ammonium chloride (430 mg, 8.04 mmol). The resulting solution was stirred overnight at reflux and then cooled to room temperature. The solid was filtered out and the filtrate was concentrated under vacuum. The residue was dissolved in ethyl acetate (200 ml) and washed with brine (100 ml), dried over Na2SO4 and concentrated under vacuum to afford 4-chloro-5-iodobenzene-1,2-diamine as a brown solid (600 mg, crude).