Synthesis
General procedure for the synthesis of 3-(trifluoromethylsulfonyl)-4-fluorobenzenesulfonamide from 3-(trifluoromethylsulfonyl)-4-fluorobenzenesulfonyl chloride: intermediate d (5.71 g) was dissolved in isopropanol (175 mL) and ammonium hydroxide (24 mL) was slowly added at -78 °C and the reaction was carried out for 1 hour. Subsequently, the reaction was quenched with 6 M HCl (88 mL) and slowly warmed up to 25 °C. The reaction mixture was concentrated, mixed with water and extracted with ethyl acetate. The organic phase was dried with anhydrous magnesium sulfate, filtered and concentrated. The concentrate was recrystallized by mixed ethyl acetate/hexane solvent to give 4.33 g of the target product 4-fluoro-3-(trifluoromethylsulfonyl)benzenesulfonamide in 80% yield.
References
[1] Patent: WO2008/61208, 2008, A2. Location in patent: Page/Page column 30; 31
[2] Synthesis, 2008, # 15, p. 2398 - 2404
[3] Patent: US2009/318689, 2009, A1. Location in patent: Page/Page column 34
[4] Chemical Communications, 2010, vol. 46, # 42, p. 8020 - 8022
[5] Patent: WO2017/101851, 2017, A1. Location in patent: Paragraph 0135; 0139
