Under N2 atmosphere, first 164 mg (1.2 mmol) anhydrous aluminium chloride is added to 12.6 g (49.3 mmol) 1-(4-chloroanilino)phthalazine in 90 ml dichloromethane, followed by 12.3 ml (98.6 mmol) trimethylsilyl cyanide. Finally, 11.5 ml (98.6 mmol) benzoyl chloride is added under ice cooling and stirred for 3 h at RT. The suspension is poured onto 0.6 ml water, filtered off, washed with water, and dried. Mixing in 150 ml boiling ethanol yields pure title compound: m.p.: 201-202° C.; Anal. calc.(C22H15N4ClO) C, 68.31%; H, 3.91%; N, 14.48%, Cl, 9.16%. found C, 68.03%; H, 3.89%; N, 14.22%, Cl, 9.42%.
