N-bromobutanimide → 3-bromopyrazolo[1,5-a]pyrimidin-5(4H)-one

Participants

Reaction Steps

A mixture of pyrazolo[1,5-a]pyrimidin-5-ol (Example 1, Step 1, 28.3 g, 210 mmol) and N-bromosuccinimide (37.3 g, 210 mmol) in dichloromethane (200 mL) and DMF (300 mL) was stirred at ambient temperature for 17 hours. The reaction mixture was concentrated and the product was precipitated using Et2O. The solids were collected by filtration and dried to afford 3-bromopyrazolo[1,5-a]pyrimidin-5-ol (40.4 g, 90%). LCMS (APCI−) m/z 211, 213 [M−H]−.

Provenance & Evidence