10.1 g (34 mmol) of 2-(4-fluorophenyl)-5-methyl-1-phenyl-hexane-1,4-dione (Example 2) and 9.3 mmol (102 mmol) of aniline in 150 ml of toluene are heated under reflux in a water separator for 24 hours with the addition of 500 mg of p-toluenesulphonic acid. After cooling and diluting with ethyl acetate, the reaction mixture is washed with 1 N hydrochloric acid and then with sodium bicarbonate solution, dried over magnesium sulphate and concentrated in vacuo. The residue is then chromatographed on silica gel.
