Trimethylsilyl chloride (125 μL, 0.982 mmol) is added to a solution of cyclohexane-1,3-dione (100 mg, 0.892 mmol), 5-formylpicolinonitrile (118 mg, 0.892 mmol) and 1-(3-(tri-fluoromethyl)phenyl)urea (183 mg, 0.829 mmol) in a mixture of N,N-dimethylformamide (670 μL) and acetonitrile (1.2 mL), and the mixture is heated at 50° C. for 1 h. The reaction mixture is cooled to room temperature and poured into a mixture of water and ice. The mixture is filtered, and the precipitate is washed with water and dried under reduced pressure. Yield: 346 mg; ESI mass spectrum [M+H]+=431, Retention time HPLC: 0.67 min (V011_S01).
