3-Chlorosulfonyl-4-fluoro-benzoic acid

456-22-4

2267-40-5

Example 2: Synthesis of 2-fluoro-5-(4-methoxybenzoyl)-benzenesulfonamide; 4-fluorobenzoic acid (8 g, 57 mmol) was slowly added to chlorosulfonic acid (58 g, 498 mmol), followed by sodium chloride (10 g, 169 mmol). After the addition was completed, the reaction mixture was heated at 160°C for 5 hours. After completion of the reaction, the reaction mixture was cooled and slowly poured into ice water. The precipitated white solid precipitate was collected by filtration and redissolved in ethyl acetate. The organic layer was washed with saturated sodium chloride solution, dried over anhydrous magnesium sulfate, filtered and concentrated under reduced pressure to remove the solvent. The residue was ground with hexane to give 7 g (51% yield) of the target product as a white solid.1H NMR (CDCl3): δ 8.78 (m, 1H), 8.52 (m, 1H), 7.5 (t, 1H).MS (m/z): 308 (M-1).