Reaction #657322

Reaction equation

2-(4-fluorophenyl)pyrazolo[1,5-a]pyrimidine

N-bromosuccinimide

water

→

3-bromo-2-(4-fluorophenyl)pyrazolo[1,5-a]pyrimidine

Yield 76.1%

Solvents

chloroform

Conditions

Workup

1. 1
   Extractionextracted with dichloromethane (3×100 mL)
2. 2
   DryingThe organic layer is dried over anhydrous magnesium sulphate
3. 3
   Filtrationfiltered
4. 4
   Concentrationconcentrated under reduced pressure
5. 5
   FiltrationThe crude material is filtered through a short pad of silica

Procedure

To a solution of 2-(4-fluorophenyl)pyrazolo[1,5-a]pyrimidine (5.8 g, 0.027 mol) in chloroform (60 mL) is added, at 0° C., N-bromosuccinimide (4.8 g, 0.027 mol). The mixture is stirred at room temperature for 1 h 30. The reaction mixture is then poured into water and extracted with dichloromethane (3×100 mL). The organic layer is dried over anhydrous magnesium sulphate, filtered and concentrated under reduced pressure. The crude material is filtered through a short pad of silica. 6 g (75%) of 3-bromo-2-(4-fluorophenyl)pyrazolo[1,5-a]pyrimidine are obtained as a brown solid which is used in the next step without further purification.

Source