The product of Step C was added to a solution of NaOH (25 g) in water (75 mL), and the reaction mixture was vigorously stirred under a nitrogen atmosphere at 60° C. for 8 minutes. The reaction mixture was then added to ice (100 g), and aqueous 6 N HCl was added until a pH of 1 was reached. The solution was extracted with ethyl acetate (3×100 mL), and the combined organic extracts were dried over magnesium sulfate, filtered, and concentrated under reduced pressure. Dichloromethane (200 mL) was added to the resulting white solid, followed by the addition of oxalyl chloride (5 mL) and N,N-dimethylformamide (0.5 mL). The reaction mixture was stirred at room temperature for 2 hours, followed by the addition of 2,4,6-trichlorophenol (10.528 g, 53.32 mmol). After stirring overnight at room temperature, the reaction mixture was concentrated under reduced pressure. Methanol was added to the resulting residue, and a solid slowly precipitated from the solution. The solid was collected by filtration to provide 8.161 g (50.43%) of the title product as a solid. 1H NMR (CDCl3) δ 7.91 (s, 1H), 7.83 (d, 1H), 7.70 (d, 1H), 7.59 (t, 1H), 7.37 (s, 4H), 5.38 (s, 1H).
