6-(Methylthio)-1H-pyrazolo[3,4]pyrimidine

148256-82-0

55084-74-7

Example 1: Synthesis of 6-(methylthio)-1H-pyrazolo[3,4-d]pyrimidine. [00197] Under ice bath cooling conditions, 4-chloro-2-(methylthio)pyrimidine-5-carbaldehyde (6.3 g, 33 mmol) was dissolved in a mixture of 160 mL of ethanol and N,N-diisopropylethylamine (DIEA, 6.6 g, 52 mmol), followed by the slow addition of hydrazine (1.8 g, 56 mmol, Alfa Aesar item #32728) which lasted for 5 minutes. The reaction mixture was continued to be stirred at 0 °C for 1 h and then transferred to an oil bath at 50 °C for 1 h. The reaction was completed by rotary evaporation. After completion of the reaction, the solvent was removed by rotary evaporation, the residue was washed with deionized water and dried under high vacuum to give the crude product (5.05 g, 91% yield). The crude product can be purified by recrystallization from a solvent mixture of methanol and water. High performance liquid chromatography (HPLC) retention time (Rt): 3.91 min. 1H nuclear magnetic resonance (NMR, CDCl3) δ: 10.95 (broad peak, 1H), 9.00 (single peak, 1H), 8.10 (single peak, 1H), 2.66 (single peak, 3H).