[Synthesis]
Step 1: Synthesis of 2-(3-fluorophenyl)thiazole-5-carboxaldehyde: To a mixed solution of 2-bromo-5-formylthiazole (0.6 g, 3.125 mmol) in toluene (2 mL) and ethanol (1 mL) was added 3-fluorophenylboronic acid (0.524 g, 3.75 mmol) and 2M aqueous sodium carbonate (in appropriate amount) under argon protection. Subsequently, tetrakis(triphenylphosphine)palladium (0.180 g, 0.156 mmol) was added, and the reaction mixture was again degassed with argon for 10 minutes and heated at 120 °C for 4 hours. After completion of the reaction, ethanol was removed by vacuum evaporation, the reaction mixture was diluted with water (10 mL) and extracted with ethyl acetate (50 mL). The organic phase was dried with anhydrous sodium sulfate, filtered and concentrated under reduced pressure to give the crude product. The crude product was purified by Biotage Isolera fast chromatography system (eluent: 6% ethyl acetate/hexane) to afford the target compound 2-(3-fluorophenyl)thiazole-5-carboxaldehyde (0.350 g, 54% yield). The product was characterized as follows: 1H NMR (400 MHz, DMSO-d6) δ 8.78 (s, 1H), 7.90 (dd, 2H), 7.61 (q, 1H), 7.44 (t, 1H); LC-MS m/z calculated value [M + H]+ 208.02, measured value 208.0. |