Sodium bicarbonate (27.9 g, 333 mmol) was added to an aqueous solution (225 mL) of resorcinol (33.0 g, 300 mmol) and iodine (81.5 g, 321 mmol). The solution was cooled to 0°C and stirred. The solution was gradually warmed to ambient temperature over 1 hour. Extraction was performed with diethyl ether, the organic layers were combined, dried over sodium sulfate, filtered, and concentrated under reduced pressure to give a white solid. The solid was ground in chloroform (100 mL) cooled to -10°C. After 30 minutes, the precipitate was filtered and washed with cold chloroform to give the title compound as a white solid (49.0 g, 69%). ¹H NMR (DMSO-d₆) Δδ 6.33 (d, 2H), 6.93 (t, 1H), 10.03 (s, 2H).
