To a solution of triphosgene (3.0 g, 10 mmol) and triethylamine (2.02 g, 20 mmol) in dry benzene (30 mL), a solution of 4-iodoaniline (4.3 g, 20 mmol) in dry benzene (15 mL) was added over 20 min. During the course of the addition, the temperature of the reaction mixture was increased from ambient to reflux temperature. After refluxing for 3 h, the reaction mixture was filtered. The filtrate was concentrated to obtain a residue, which was subjected to distillation under reduced pressure to afford a colorless liquid. Yield 2.21 g (45.2%).