114078-88-5

122481-11-2

114078-88-5

The general procedure for the synthesis of 5-bromo-1,2,3-triazine using 4-bromo-1H-pyrazol-1-amine as starting material was as follows: dichloromethane (200 mL) and water (76 mL) were added to a reaction flask, and the mixture was cooled to 0 °C with stirring. Subsequently, sodium periodate (29.4 g, 137 mmol) was added in batches. After the addition was completed, the reaction mixture was continued to be stirred at 0°C for 12 hours. After completion of the reaction, the mixture was warmed up to 25 °C for partitioning operation. The aqueous phase was extracted with dichloromethane (100 mL x 3) and all organic phases were combined. The organic phase was washed with saturated brine (250 mL) and then dried with anhydrous sodium sulfate. The dried organic phase was filtered and the filtrate was concentrated to obtain the crude product. The crude product was purified by silica gel column chromatography (eluent ratio of petroleum ether: ethyl acetate= 10:1), and finally 5-bromo-1,2,3-triazine was obtained as a white solid (8.8 g, two-step overall yield 73.5%).