A solution of 0.26 g (1 mmol) of (4′-chlorobiphenyl-4-yl)propynoic acid and 0.12 mL (1.1 mmol) of N-methylmorpholine in 20 mL of absolute THF is combined at −15° C. with 0.14 mL (1.1 mmol) of isobutyl chloroformate and stirred for ten minutes. Then 0.226 g (1.1 mmol) of 4-(4-methylpiperazin-1-ylmethyl)phenylamine dissolved in 7 mL of THF is added and the reaction mixture is stirred for 2 hours until ambient temperature is reached. The reaction mixture is evaporated down and the residue is dissolved in dichloromethane. The organic phase is washed twice with water and then dried over sodium sulfate. The desiccant is filtered off and the solvent is distilled off. The residue is triturated with ether and suction filtered. The purification is carried out by column chromatography on silica gel (dichloromethane/methanol/ammonia (90/10/0.1)). Yield: 60 mg (14% of theory); melting point: 182° C.-185° C.; C27H26ClN3O (M=443.97); calc.: molecular ion peak (M+H)+: 444/446 (Cl); found: molecular ion peak (M+H)+: 444/446 (Cl); Rf value: 0.4 (silica gel, dichloromethane/methanolic ammonia (90:10:0.1)).
