Abstract: The sulfonylurea herbicide rimsulfuron 1 (N-((4, 6-dimethoxypyrimidin-2-yl) aminocarbonyl)-3-(ethylsulfonyl)-2-pyridinesulfonamide) in aqueous solutions of KOH, NaOH, NH4OH, or dilute HCl, and thermally (rimsulfuron or monomethylated rimsulfuron at the sulfonamide hydrogen) was transformed by SO2 extrusion and intramolecular nucleophilic substitution into 2-(N-(4, 6-dimethoxy) pyrimidin-2-yl) amino 3. In mild ...