400 mg (1.2 mmol) of 4-chloro-6,8-dimethoxy-1-(4-methoxyphenyl)phthalazine dissolved in 5 mL of toluene, 276 mg (1.4 mmol) of 4-amino-1-benzylpiperidine, 163 mg (1.7 mmol) of sodium tert-butoxide, 6 mg (0.009 mmol) of BINAP (2,2′-bis(diphenylphosphino)-1,1′-binaphthyl) and 5.5 mg (0.006 mmol) of tris(dibenzylideneacetone)dipalladium are successively introduced into a tube under argon. The tube is hermetically sealed and the mixture is stirred at 80° C. for 24 hours. After cooling to room temperature, the reaction medium is hydrolysed with sodium hydrogen carbonate solution and then extracted with ethyl acetate. The organic phase is washed with water and with brine, dried over anhydrous sodium sulfate and then evaporated under reduced pressure. The residue obtained is purified by chromatography on a column of silica gel (solvent: 95/5 (v/v) dichloromethane/methanol). The oily product obtained forms a solid by trituration in ethyl ether. 270 mg of product are obtained in the form of a beige-coloured powder.
