[NH2:1][C:2]1[C:7]([Br:8])=[CH:6][C:5]([Br:9])=[CH:4][C:3]=1[S:10]([OH:12])=[O:11].O.Cl[CH:15]([F:17])[F:16]>C(O)(C)C.[OH-].[Na+]>[Br:8][C:7]1[CH:6]=[C:5]([Br:9])[CH:4]=[C:3]([S:10]([CH:15]([F:17])[F:16])(=[O:12])=[O:11])[C:2]=1[NH2:1]A solution of 2-amino-3,5-dibromobenzenesulfinic acid (7.98 g; 0.025 mol) in a mixture of isopropyl alcohol (100 ml) and sodium hydroxide (8.0 g of 50% aqueous) and water (2 ml) is warmed to 40° C. Chlorodifluoromethane is added slowly through a gas inlet tube over a period of 3 hours. The reaction mixture exotherms to 55° C. The reaction mixture is poured into water (500 ml) and the solution is extracted with methylene chloride (2×100 ml). The combined extracts are washed with saturated NaHCO3 (100 ml), saturated NaCl (100 ml), then dried over MgSO4. The solvent is evaporated under vacuum yield 0.9 g of the title product, m.p. 84°-88° C.
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