Trimethylsilyl chloride (1 M in dichloromethane, 4.90 mL, 4.90 mmol) is added to a solution of cyclohexane-1,3-dione (0.50 g, 4.46 mmol), 3-fluoro-4-formylbenzonitrile (0.67 g, 4.46 mmol) and 1-(3-(trifluoromethyl)phenyl)urea (0.91 g, 4.46 mmol) in a mixture of N,N-dimethylformamide (2.0 mL) and acetonitrile (2.0 mL). The mixture is stirred at room temperature for 45 min and then poured into ice water. The mixture is stirred over night at room temperature, and the precipitate is filtered and dried. Yield: 1.8 g; ESI mass spectrum [M+H]+=448, Retention time HPLC: 1.02 min (Z018_S04).
