N-(2-bromoethyl)-4-chlorobenzenesulfonamide

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A two-necked flask equipped with a condenser and a rubber septum was charged with N-(2-bromoethyl)-4-chlorobenzenesulfonamide (2.80 g, 9.4 mmol) and anhydrous benzene (50 mL). The reaction vessel was degassed and backfilled with argon and then heated to reflux. Under reflux, a solution of tributyltin hydride (5.05 mL, 18.8 mmol) and 2,2′-azobis(2-methylpropionitrile) (0.77 g, 4.7 mmol) in anhydrous benzene (25 mL) was added slowly over 8 hours using a syringe pump, and the mixture was refluxed for a further 12 hours. After cooling, the reaction mixture was concentrated and the residue purified by silica gel column chromatography (0-40% ethyl acetate in methylene chloride) followed by preparative TLC (1:2 ethyl acetate in hexanes) to afford the pure product as a white foam (0.085 g, 4%). 1H NMR (300 MHz, CDCl3) δ 7.77 (d, 1H, J=8.4 Hz), 7.37 (dd, 1H, J=8.1, 2.1 Hz), 7.26 (s, 1H), 4.47 (t, 1H, J=7.5 Hz), 3.83 (dt, 2H, J=7.5, 6.0 Hz), 3.00 (t, 2H, J=6.0 Hz). A two-necked flask equipped with a condenser The reaction vessel was degassed heated to reflux Under reflux the mixture was refluxed for a further 12 hours After cooling the reaction mixture was concentrated the residue purified by silica gel column chromatography (0-40% ethyl acetate in methylene chloride)

Conditions: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a stirred mixture of 4-chlorobenzenesulfonyl chloride (5.0 g, 23.7 mmol) and 2-bromoethylamine hydrobromide (5.4 g, 26.3 mmol) in anhydrous methylene chloride (50 mL) at 0° C. was slowly added N,N-diisopropylethyl amine (8.6 mL, 52.1 mmol) and the mixture was stirred at 0° C. for 1 hour. The reaction mixture was washed sequentially with water, 2N aqueous hydrochloric acid, saturated aqueous sodium carbonate, and saturated aqueous sodium chloride. The organic layer was dried (anhydrous sodium sulfate), filtered, and concentrated in vacuo to afford a white solid (7 g, 99%). 1H NMR (300 MHz, CDCl3) δ 7.82 (d, 2H, J=8.7 Hz), 7.52 (d, 2H, J=8.7 Hz), 4.96 (s, 1H), 3.50-3.30 (m, 4H). The reaction mixture was washed sequentially with water, 2N aqueous hydrochloric acid, saturated aqueous sodium carbonate, and saturated aqueous sodium chloride The organic layer was dried (anhydrous sodium sulfate) filtered concentrated in vacuo