A solution of 0.275 g of 1-(4-bromo-phenyl)-4-methyl-piperazine in tetrahydrofuran (90 mL) is cooled to −78° C. and treated with 1.44 mL of tert-butyllithium (1.5 M in pentane). After 15 min at −78° C. the reaction mixture is treated with 0.1 g of 4-chloro-N-methoxy-N-methyl-3-sulfamoyl-benzamide in tetrahydrofuran (3 mL). The temperature is then increased slowly to 0° C. and after completion the reaction is quenched by addition of 2 mL of saturated aqueous ammonium chloride and extracted with diethyl ether. The organics are washed with water, dried (magnesium sulfate) and concentrated to give 0.32 g of crude product which is purified by silica gel chromatography (95:5 methylene chloride/methanol) to give 2-chloro-5-[4-(4-methyl-piperazin-1-yl)-benzoyl]-benzenesulfonamide as a tan powder. MS (m/z): 394 (M+1); Rf 0.06 (95:5 methylene chloride/methanol).
