A stirred suspension of 344 (500 mg, ˜2 mmol), 3,4-difluoronitrobenzene (795 mg, 5 mmol) and cesium carbonate (1.63 g, 5 mmol) in anhydrous DMF (50 ml) was heated at 85° C. under nitrogen for 7 h. The temperature was allowed to cool down to room temperature. The reaction mixture was poured into water, and extracted with dichloromethane. The combined organic phase was concentrated and directly purified twice by flash column chromatography (eluents 2% of NH4OH in methanol/CH2Cl2: 5/95 to 10/90) to afford title compound 345 (144 mg, 19% yield) as a sticky yellow solid. MS (m/z): 384.0 (M+H)+.
