Potassium Bromate
2-Iodobenzoic acid
sulfuric acid
Acetic anhydride
TsOH.H₂O

Potassium bromate (15.2 g, 91 mmol, 1 equiv) was added over a 30 minute period to a vigorously stirred solution of 2-iodobenzoic acid (17.2 g, 69 mmol, 0.75 equiv) and 14.6 mL of 0.73 M H₂SO₄. The temperature of the reaction was maintained below 55 ^oC by the aid of an ice bath. The resulting mixture was warmed to 65 ^oC and stirred for 4 h. The slurry was cooled to 0^oC, filtered and washed with water (200 mL), ethanol (2 x 20 mL) and dry ether (3 x 20 mL) leaving a slightly pink solid. To a stirring solution of the pink solid [1-hydroxy-1,2-benziodoxol-3(1H)-one] (20g, 71 mmol, 1 equiv) in acetic anhydride (80 mL, 286 mmol, 4 equiv) was added TsOH.H₂O (100 mg). The flask was equipped with a drying tube and was heated in an oil bath at 80 ^oC for 2 h. The resulting brown slurry was cooled to 0 ^oC in ice-water and filtered thruogh a fritted glass funnel. The resulting white solid was washed with anhydrous ether (5x50 mL) resulting in a white crystalline solid (15.2 g, 40 %)

1H nmr (300 MHz, CdCl₃) 2.26 (3H, s), 7.71 (1H, dt, J=0.9, 7.8 Hz), 7.92 (1H, dt, J=1.5, 7.4 Hz), 8.00 (1H, d, J=8.1 Hz), 8.25 (1H, dd, J=1.2, 7.5 Hz)

Dess, D.B.; Martin, J.C.; J. Org. Chem., 1983, 48, 4156; Ireland, R.E.; Liu, L.; J. Org. Chem., 1993, 58, 2899.

Greenbaum, F.R.; Am. J. Pharm, 1936, 17.