Br2 (3 mL) was added dropwise to a solution of sodium hydroxide (7.0 g NaOH (0.18 mol) was dissolved into 30 mL of H2O), cooled on an ice bath, and further stirred for 20 min. The solution was transferred to a funnel for the addition dropwise to a solution of 4,4',4''-triacetyltriphenylamine (5.4 mmol) in 1,4-dioxane (50 mL) at 45 °C. The solution was acidified with HCl. The solid was separated via filtration and dried under a vacuum. The solid was recrystallized using acetic acid to afford a white solid.