1027345-07-8

General procedure for the synthesis of 3-(trifluoromethylsulfonyl)-4-fluorobenzenesulfonyl chloride from 1-fluoro-2-(trifluoromethanesulfonyl)benzene: 1-fluoro-2-(trifluoromethanesulfonyl)benzene (10.00 g, 43.83 mmol) was dissolved in chlorosulfuric acid (35.00 mL) and the reaction was heated for 5 hours at 120°C. After the reaction was completed, the mixture was slowly poured into a mixture consisting of crushed ice (100 g) and water (300 mL). The reaction mixture was extracted with dichloromethane (80 mL x 2) and the combined organic phases were washed with distilled water (200 mL x 2). The organic phase was dried over anhydrous sodium sulfate and concentrated under reduced pressure to afford 3-(trifluoromethylsulfonyl)-4-fluorobenzenesulfonyl chloride (12.60 g, 38.57 mmol, 88% yield), which could be used for the next reaction without further purification. Mass spectrum (ESI) m/z = 307 [M-Cl+OH-H]. 1H NMR (400 MHz, DMSO-d6): δ 8.25 (m, 1H), 8.15 (m, 1H), 7.73 (m, 1H).

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