GENERAL METHOD: p-Nitrobenzene methanesulfonyl fluoride (0.5 mmol) was dissolved in acetonitrile (1 mL), and 1,8-diazabicycloundec-7-ene (DBU, 22 μL, 0.15 mmol, 0.3 eq.) and trimethylsilyl azide (TMSN3, 50 μL, 0.375 mmol, 0.75 eq.) were added in sequence. The reaction mixture was stirred at room temperature for 15 min before trimethylsilyl azide (TMSN3, 50 μL, 0.375 mmol, 0.75 equiv) was added again. Stirring was continued for 45 min and after completion of the reaction, the reaction was filtered through a short column of silica gel, eluting with ethyl acetate (50 mL). The filtrate was concentrated under reduced pressure to remove the volatile solvent to afford the target product 2,4-dinitrobenzenesulfonamide.
