Use of the crude acrolein coming from Example 4a. To a suspension of 3-[3-(4-Fluorophenyl)-1-(1-Methylethyl)-1H-Indole (130.7 g), phosphorus oxychloride (114.6 g) in acetonitrile (128 ml) cooled at 5° C. a solution of crude acrolein (116.9 g from Example 4a) in acetonitrile (145 ml) is added dropwise in 60 minutes. The reaction mixture is then warmed to 60° C. and kept under stirring at 60° C. for 6 hours; water (1100 ml) is added and after 1 hour at 60° C. the formed solid is filtered on Buchner and washed with water (250 ml×3). The wet solid (131 g) is dissolved in toluene (1050 ml), celite (2.7 g) and charcoal (4 g) are added and the mixture is stirred at room temperature for 30 minutes. After filtration of the solid, the mixture is washed with water (500 ml×2), the phases are separated, the organic solvent is distilled off at reduced pressure and the residue is dissolved at 75° C. with isopropanol (260 ml). The solution is cooled at 10° C. and stirred for 1 hour. The precipitate is filtered on Buchner, washed with isopropanol (60 ml×3) and dried at 60° C. under vacuum. 84.2 g (53% molar yield) of the product are obtained.
