1H-Pyrazolo[3,4-d]pyrimidine, 1-methyl- (6CI,8CI,9CI) synthesis

Yield:6288-86-4 93%

Reaction Conditions:

with trichlorophosphate in dichloromethane at 80 - 90;Inert atmosphere;

Steps:

1 Standard procedure for the preparation of pyrazolo[3,4-d]pyrimidine products 12a-e, 13a-e, and 14a-e

General procedure: The reliable procedure involved the treatment of N-1-phenyl-5-aminopyrazoles, N-1-phenyl-5-aminopyrazoles (1a-e, 1.0 equiv), N-1-(2-pyridinyl)-5-aminopyrazoles (4a-e 1.0 equiv), or N-1-(2-quinolinyl)-5-aminopyrazoles (5a-e, 1.0 equiv) with catalytic amount of POCl₃ (～3 equiv) with formamide (2 mL) in CH₂Cl₂ solution at 80-90 °C within 0.5-1 h. When the reaction was completed, the reaction mixture was concentrated, added to saturate sodium bicarbonate (15 mL), and extracted with dichloromethane (15 mL). The organic extracts were dried over MgSO₄, filtered, and concentrated under reduced pressure. The residues were purified by column chromatography on silica gel to give the corresponding pyrazolo[3,4-d]pyrimidine products 12a-e, 13a-e or 14a-e were obtained in 91-96%, 81-88%, or 82-91% yield, respectively.

References:

Chang, Chun-Hsi;Tsai, Henry J.;Huang, Yu-Ying;Lin, Hui-Yi;Wang, Li-Ya;Wu, Tian-Shung;Wong, Fung Fuh [Tetrahedron,2013,vol. 69,# 4,p. 1378 - 1386] Location in patent:supporting information