4-(Bis(4-iodophenyl)amino)benzaldehyde (3) was synthesized as follows: in a 100 mL two-necked flask equipped with a nitrogen inlet, a magnetic stirrer and a condenser, 4-(diphenylamino)benzaldehyde (2) (3.8 g, 13.9 mmol), potassium iodide (3.0 g, 18.1 mmol), acetic acid (45.0 mL), and deionized water (5.0 mL ). The reaction mixture was heated to 80 °C and potassium iodate (2.98 g, 13.9 mmol) was added quickly. The resulting mixture was stirred continuously at 80 °C for 5 hours. Upon completion of the reaction, the solution was cooled to room temperature and slowly poured into ice water with stirring. The resulting yellow precipitate was collected by filtration and washed with 5% mass fraction NaHSO3 solution (40.0 mL). After filtration, the target product 4-(bis(4-iodophenyl)amino)benzaldehyde (3) was obtained as a yellow solid (7.0 g, 13.4 mmol, 96% yield). The 1H NMR spectrum of the product was in agreement with literature reports (Ning et al., 2007).
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