1146290-36-9

1242618-52-5

1146290-36-9

General procedure for the synthesis of 2-fluoro-4-nitrobenzenesulfonyl chloride from 1-(benzylsulfonyl)-2-fluoro-4-nitrobenzene: To a cooled 1-(benzylsulfonyl)-2-fluoro-4-nitrobenzene (10.5 g, 40.0 mmol) solution of acetonitrile-acetic acid-water (400 mL, 5 mL, 10 mL) was added in batches 1,3-dichloro-5,5-dimethyl-acetonitrile ( 15.8 g, 80.0 mmol). The reaction was carried out at 0°C. After stirring at 0°C for 3 h, the reaction mixture was concentrated in vacuum to near dryness. The crude product was diluted with dichloromethane (500 mL) and the solution was cooled to about 0°C. A 5% aqueous sodium bicarbonate solution (550 mL) was added slowly at a temperature below 10°C and the mixture was stirred at 0°C for 15 minutes. The organic layer was separated, washed with cooled brine, dried over anhydrous sodium sulfate, filtered and concentrated in vacuum. The resulting liquid product was used for subsequent reactions without further purification. A small amount of analytically pure sample was obtained by purification on preparative thin layer chromatography plate (9:1 hexane/ethyl acetate) to afford 2-fluoro-4-nitrobenzenesulfonyl chloride (71% yield) as a light yellow solid with melting point 44-45 °C (literature value 45-47 °C).1H NMR (CDCl3) δ 8.32 (dd, J = 9.0,5.0 Hz, 1H, Ar-H), 7.64 (dd, J = 7.5,2.5 Hz, 1H, Ar-H), 7.61-7.57 (m, 1H, Ar-H).