GENERAL METHOD: Benzenesulfonamide (2 mmol) was dissolved with isopropanol (10 mmol) in 1,4-dioxane (3 mL), followed by the addition of trifluoromethanesulfonic anhydride (Tf2O, 2 mmol). The reaction mixture was sealed and the reaction was stirred at 120 °C until thin layer chromatography (TLC) monitoring showed that the reaction was complete. After completion of the reaction, the reaction was quenched with saturated aqueous sodium bicarbonate (NaHCO3). The reaction mixture was extracted three times with ethyl acetate (EtOAc) and the organic phases were combined and dried with anhydrous sodium sulfate (Na2SO4). After concentration under reduced pressure to remove the solvent, the residue was purified by fast column chromatography using petroleum ether (PE) and ethyl acetate (EtOAc) (3:1, v/v/v) as eluents to give pure N-isopropylbenzenesulfonamide (IBSA).
