N,N-Dimethylaniline → 4-Chloro-1H-pyrazolo[3,4-d]pyrimidine

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Reaction Steps

To a mixture of commercially available 4-hydroxypyrazolo[3,4-d]pyrimidine (78) (Acros, 14.5 g, 106.5 mmol) stirred in POCl3 (375 mL) was added N,N-dimethylaniline (21 mL). The mixture was refluxed for 1.5 h. After cooling, excess POCl3 was removed by rotarty evaporation and pumped on high vacuum before pouring over 500 mL ice while stirring. The mixture was stirred for 10 min before extracting with ethyl ether (6×250 mL). The combined organic layer was washed with ice water (3×100 mL) and dried over MgSO4 and filtered. The ethyl ether was stripped and the resulting pale yellow solid (10 g, 61%) was pumped on high vacuum overnight. Compound 79: mp>300° C., dec. 125° C.; MS (ES+ calculated: 154.56; found: 156.21 M+H). HPLC (98% purity, retention time 6.033 minutes—method D) 1H NMR (400 MHz, DMSO-d6) δ 14.55 (bs, 1H), 8.84 (s, 1H), 8.46 (s, 1H).

Provenance & Evidence