A mixture of 4-Isothiocyanato-2-trifluoromethylbenzonitrile (96) (36 mg, 0.16 mmol) and 4-[4-(1-Cyanocyclopentyl amino)phenyl]butanenitrile (93) (20 mg, 0.08 mmol) in DMF (1 mL) was heated under microwave irradiation at 80° C. for 6 h. To this mixture was added methanol (10 mL) and aq. 1 N HCl (3 mL). The second mixture was refluxed for 1.5 h. After being cooled to room temperature, the reaction mixture was poured into cold water (20 mL) and extracted with ethyl acetate (30 mL). The organic layer was dried over MgSO4, concentrated and the residue was purified by silica gel column chromatography (hexane:ethyl acetate, 2:1) to give 4-(1-(4-(3-Cyanopropyl)phenyl)-4-oxo-2-thioxo-1,3-diazaspiro[4.4]non-3-yl)-2-trifluoromethylbenzonitrile (92) [ND-2]
