GENERAL STEPS: A mixture of 2-amino-4,6-dichloropyrimidine-5-carbaldehyde (1.92 g, 10 mmol) and triethylamine (1.59 mL, 11.5 mmol) was added to a solvent mixture of THF (40 mL) and H2O (4 mL) at room temperature. Subsequently, hydrazine (64%, 486 μL, 10 mmol) was added slowly and dropwise. The reaction mixture was stirred continuously for 4 h at room temperature. Upon completion of the reaction, the volatiles were removed by distillation under reduced pressure. The residue was precipitated with water, and the resulting precipitate was washed with water and dried under vacuum to afford the target product 4-chloro-1H-pyrazolo[3,4-D]pyrimidin-6-amine (1.8 g, quantitatively) as a yellow solid.13C NMR (DMSO-d6, 75 MHz) δ: 161.5 (C-2), 157.5 (C-4), 153.2 (C-7a), 132.7 (C-5), 105.8 (C-4a).MS (m/z): 170 [M + H]+.
![4-CHLORO-1H-PYRAZOLO[3,4-D]PYRIMIDIN-6-AMINE](/CAS/GIF/100644-65-3.gif)