2380-63-4

83255-86-1

The general procedure for the synthesis of 3-bromo-1H-pyrazolo[3,4-d]pyrimidin-4-amine using 4-aminopyrazolo[3,4-d]pyrimidine as starting material was as follows: 1H-pyrazolo[3,4-d]pyrimidin-4-amine (20.0 g, 148.0 mmol) and N-bromosuccinimide (27.7 g, 155.4 mmol) were suspended in N,N- dimethylformamide (DMF, 400 mL). The reaction mixture was heated to 80 °C and the reaction was stirred at this temperature for 2.5 hours. Upon completion of the reaction, the mixture was cooled to room temperature, followed by slow dropwise addition of water (800 mL) to quench the reaction. The resulting precipitate was collected by filtration and suspended in saturated sodium sulfite solution (100 mL). The solid product was filtered again and washed sequentially with water (3 x 100 mL) and cold ethanol (2 x 50 mL). Finally, the product was dried under vacuum to afford 3-bromo-1H-pyrazolo[3,4-d]pyrimidin-4-amine as a beige solid (22.7 g, 105.9 mmol, 72% yield).