150 mg (0.42 mmol) of 4-isopropyl-N-(6-piperazin-1-yl-pyridin-3-yl)-benzenesulfonamide from Example 7 and 51 mg (0.46 mmol) of cyclohexanealdehyde were dissolved in 5 ml of dichloromethane and 40 μl (0.62 mmol) of glacial acetic acid under a nitrogen atmosphere. 133 mg (0.63 mmol) of sodium trisacetoxyborohydride were then added. The mixture was stirred at room temperature for 90 minutes and, after that, the solvent was evaporated down to dryness. The resulting residue was taken up in water and this mixture was made to pH>11 with a 1N aqueous solution of sodium hydroxide. After that, the aqueous reaction mixture was extracted with diethyl ether. After the organic phase had been dried over sodium sulfate and the solvent had been filtered and evaporated down to dryness, the resulting residue was converted into the hydrochloride with ethereal hydrochloric acid, resulting in 156 mg (76% of theory) of the title compound.
