[Step 1: Method for synthesizing 2-iododibenzo[b,d]furan] In a 500 mL three-necked flask, 8.4 g (50 mmol) of dibenzofuran, 6.2 g (25 mmol) of iodine, 5.7 g (25 mmol) of phthalic acid, 150 mL of glacial acetic acid, 30 mL of water, and 500 μL of sulfuric acid were added to a suspension that was heated to 60 °C and stirred at that temperature for 4.5 hours to initiate the reaction. After the reaction was completed, the reaction mixture was continued to be stirred at room temperature for 16 hours. The resulting precipitate was collected by filtration and the resulting solid was dissolved in 150 mL of toluene. Subsequently, the toluene solution was washed three times with water. Magnesium sulfate was added to the washed toluene solution to remove water. After filtration to remove the magnesium sulfate, the filtrate was concentrated. Hexane was added to the concentrate and sonicated. The precipitated solid was collected by filtration and dried to give the target product 2-iododibenzo[b,d]furan as 11.3 g white powder in 77% yield. The reaction scheme of the synthetic method is shown below (B-1). The compounds obtained in step 1 were subjected to nuclear magnetic resonance (NMR) analysis. 1H NMR (CDCl3, 300 MHz) data were as follows: δ (ppm) = 7.33-7.38 (m, 2H), 7.48 (dt, J = 1.5 Hz, 8.4 Hz, 1H), 7.56 (d, J = 8.1 Hz, 1H), 7.72 (dd, J = 2.1 Hz, 8.4 Hz, 1H), 7.95 (d, J = 7.8 Hz, 1H), 8.27 (d, J = 1.5 Hz, 1H).The results of NMR analysis confirmed that the resulting product was 2-iododibenzo[b,d]furan.
