775331-26-5

1788-08-5

Under nitrogen protection, 4-((trimethylmethylsilyl)ethynyl)benzenesulfonamide (1.69 g, 3.13 mmol) prepared in step 1 was dissolved in anhydrous tetrahydrofuran and tetrabutylammonium fluoride (TBAF, 10 mL, 1.0 M solution in tetrahydrofuran, 10 mmol) was added. The reaction mixture was stirred at room temperature. The progress of the reaction was monitored by silica gel thin layer chromatography (TLC, unfolding agent ratio 1:1 hexane:ethyl acetate). Upon completion of the reaction, 10% hydrochloric acid and ethyl acetate were added. The organic layer was separated, washed twice sequentially with water and aqueous ammonium chloride, dried over anhydrous sodium sulfate, and concentrated under reduced pressure to afford the target product, 4-alkynylbenzenesulfonamide, 0.748 g in 62% yield. High-resolution electrospray ionization mass spectrometry (ESHRMS) measured m/z of 199.0506 ([M+NH4]+, calculated value of 199.0541 for C8H7NO2SNH4).