To a solution of 0.108 g (0.25 mmol) of 4-(3-{4-[l-(2-ethoxyethyl)-1H-indol-3-yl]-piperidin-1-yl}-propoxy)-benzonitrile in 1.5 mL of anhydrous DMF, 0.110 g (2 mmol) of ammonium chloride and 0.135 g (2 mmol) of sodium azide were added. The crude mixture was heated at 110° C. for 18 hours and after cooling at room temperature, 1 mL of an aqueous solution of 2N sodium hydroxide was added. The mixture was taken to pH=6 and the aqueous phase was extracted with ethyl acetate. After purification by flash cromatography over silica gel 0.05 g (41% yield) of the desired product were obtained.
