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 %)

This procedure has been succesfully carried out numerous times within the group on scales ranging from 5 g to 30 g of the produced D-M reagent. The literature claims that the first formed product is explosive but we have had no problems thus far. However, the preparation should only be carried out behind a blast shield. One problem with the first part of this procedure is that stirring becomes very difficult when addition of the potassium bromate is almost complete and hot pockets are produced in the mixture. This is prevented by the use of an overhead stirrer. The D-M reagent should be stored in a freezer in an amber bottle.

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.