Potassium Carbonate → Acifluorfen-methyl

To a flask fitted with a drying tube is charged DMSO (10 ml), 2-chloro-4-trifluoromethylphenol (3.93 g, 0.02 mole) and anhydrous potassium carbonate (2.76 g, 0.02 mole). Then methyl 5-chloro-2-nitrobenzoate (4.3 g, 0.02 mole) is added and the reaction mixture warmed to 50° C. for 3 hours. (Gas-liquid chromatography analysis suggested a low conversion to desired product.) The temperature is raised to 60° C. for 16 hours and then to 70° C. for 16 hours. Additional potassium carbonate (1.38 g, 0.01 mole) is added and heating at 70° C. is continued for an additional 5 days, the reaction mixture is cooled to room temperature, poured into a benzene/hexane cosolvent and extracted twice with water. The organic layer is dried with anhydrous sodium sulfate, filtered and the solvent removed under vacuum (110° C., 0.1 mm) to afford 2.0 g, (27% yield) of methyl 5-(2-chloro-4trifluoromethylphenoxy)-2-nitrobenzoate which is determined by spectral data to be identical with the product of Example 1B.