Reaction #657321

Reaction equation

NH4OH

water

3-(4-fluorophenyl)-1H-pyrazole-5-amine

1,1,3,3-tetramethoxypropane

→

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

Yield 113.9%

Solvents

acetic acid

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

Procedure

To a solution of 3-(4-fluorophenyl)-1H-pyrazole-5-amine (5.0 g, 0.028 mol) in acetic acid (50 mL) is added 1,1,3,3-tetramethoxypropane (5.79 g, 0.035 mol). The mixture is stirred at 110° C. for 1 h. The reaction mixture is then poured into water, basified with NH4OH and extracted with dichloromethane (3×100 mL). The organic layer is dried over anhydrous magnesium sulphate, filtered and concentrated under reduced pressure. 6.8 g (79%) of 2-(4-fluorophenyl)pyrazolo[1,5-a]pyrimidine are obtained as a beige solid which is used in the next step without further purification.

Source