Solid Na2CO3 (400 mg, 3.8 mmol, 3.8 eq) is added to a solution of 1-benzyl-4-chlorophthalazine (250 mg, 0.98 mmol, 1 eq) and (5)-2-methyl-piperazine (400 mg, 4.0 mmol, 4.0 eq) in dioxane (5 mL). The resulting suspension is heated at 100° C. for 48 h. The reaction mixture is concentrated, EtOAc (50 mL) and water (15 mL) are added. The organic fraction washed with water and then brine, then is dried over sodium sulfate. The solvent is evaporated under reduced pressure to afford the title compound as a white solid (200 mg, 64% yield).
