To a solution of 1-(6-chloronaphthalen-2-ylsulfonyl)-piperazine (0.450 g, 1.45 mmol) in methylene chloride (100 mL) and pyridine (0.154 mL) was added dropwise 6-chloropyridazine-3-carbonyl chloride (1.74 mmol). After the addition of the acid chloride, pyridine (0.154 mL) was added, and the reaction mixture was stirred overnight. The reaction mixture was diluted with chloroform (500 mL), washed with saturated sodium bicarbonate (200 mL), water (200 mL),and brine and dried over MgSO4. After filtration and evaporation of the solvent, trituration of the residue with ethyl acetate and filtration gave the product as a white powder (0.5 g, 76%)
