2-Ethylsulfonylimidazo[1,2-a]pyridine-3-sulfonamide

2-Ethylsulfonylimidazo[1,2-a]pyridine-3-sulfonamide is a degradation product of sulfosulfuron. Sulfosulfuron is a widely used wheat herbicide.

25.7 g of the reactant 2-ethylthioimidazo[1,2-a]pyridine-3-sulfonamide (0.1 mol), 0.1 g of sodium tungstate as a catalyst, and 250 ml of acetic acid as a solvent were placed in a reaction vial and heated up to 70 C, and 27.2 g of hydrogen peroxide (0.24 mol) as an oxidizing agent at a concentration of 30 wt% was slowly added dropwise into the vial to carry out oxidation reaction. The reaction was continued to be held at the end of the dropwise addition for 5 h. Subsequently, the reacted system was cooled down to 15 C. The reaction was carried out at the end of the reaction. The filter cake was washed with 120 ml of water and dried at 80 C for 12 h. 26.0 g of the product 2-ethylsulfonylimidazo[1,2-a]pyridine-3-sulfonamide (sulfonylsulfonamide) was obtained as a rice-white solid with the purity up to 98%, the melting point of 198.5-201.6 C, and the yield up to 88%.