Pyridine → N-(4-ethynylphenyl)methanesulfonamide

In a 2 L, 3-neck round-bottom flask equipped with an overhead stirrer was added 4-ethynylaniline (30 g, 256 mmol) and pyridine (42.5 ml, 525 mmol) in dichloromethane (512 ml) to give an orange solution. The mixture was cooled to 5° C. and methanesulfonyl chloride (19.96 ml, 256 mmol) was added drop wise over 15 min. The reaction solution was stirred at 5° C. for 2 h and washed with 1M aqueous HCl (3×250 mL). The dichloromethane layer was then washed sequentially with saturated aqueous NaHCO3, water, and saturated aqueous NaCl. The dichloromethane layer was dried over sodium sulfate and treated simultaneously with decolorizing charcoal for 30 min, the solution then filtered through Celite and the filtrate was concentrated. The pink/orange solid was dissolved in a minimal amount of hot ethyl acetate (50-75 mL) and slowly diluted with hexanes (500-600 ml) to give orange crystals that were collected by filtration and dried to provide the title compound (40.0 g, 80%).