Reacción #657320

Ecuación de reacción

NH4OH

water

4-bromo-3-phenyl-1H-pyrazole-5-amine

1,1,3,3-tetramethoxypropane

→

3-bromo-2-phenylpyrazolo[1,5-a]pyrimidine

Rendimiento 76.6%

Disolventes

acetic acid

Condiciones de reacción

Tratamiento posterior

1. 1
   Extracciónextracted with dichloromethane (3×100 mL)
2. 2
   SecadoThe organic layer is dried over anhydrous magnesium sulphate
3. 3
   Filtraciónfiltered
4. 4
   Concentraciónconcentrated under reduced pressure
5. 5
   OtroThe crude material is purified by column chromatography

Procedimiento

To a solution of 4-bromo-3-phenyl-1H-pyrazole-5-amine (5.0 g, 0.02 mol) in acetic acid (50 mL) is added 1,1,3,3-tetramethoxypropane (4.14 g, 0.025 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. The crude material is purified by column chromatography using silica gel in dichloromethane and ethyl acetate (1:0 to 95:5) as eluent and 4.2 g (75%) of 3-bromo-2-phenylpyrazolo[1,5-a]pyrimidine are obtained as a beige solid.

Fuente