B. Synthesis of 2-amino-4-iodobenzoic acid: 4-Iodo-2-nitrobenzoic acid (20 g, 68 mmol, 1.0 eq.) was dissolved in 200 mL of ethyl acetate, followed by addition of stannous chloride dihydrate (SnCl2-2H2O, 46 g, 204 mmol, 3.0 eq.) in three batches. The reaction mixture was stirred at room temperature for 16 hours. Upon completion of the reaction, the pH of the mixture was adjusted slowly by adding saturated aqueous sodium bicarbonate solution to 9. The precipitated solids were removed by filtration through diatomaceous earth and washed with distilled water. The aqueous layer in the filtrate was separated and acidified with concentrated hydrochloric acid to pH=2. The precipitated solid was collected by filtration and dried to give 2-amino-4-iodobenzoic acid as a white solid (19 g, 68 mmol, 100% yield).1H NMR (400 MHz, CD3OD) and 1H NMR (500 MHz, CDCl3) data were as follows: δ 7.56 (d, J=8.5 Hz, 1H), 7.08 (s, 1H), 6.99 (d, J=8.5 Hz, 1H), 5.71 (br s, 2H).
