反応 #657320

反応方程式

NH4OH

water

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

1,1,3,3-tetramethoxypropane

→

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

収率 76.6%

溶媒

acetic acid

反応条件

後処理

1. 1
   抽出extracted with dichloromethane (3×100 mL)
2. 2
   乾燥The organic layer is dried over anhydrous magnesium sulphate
3. 3
   ろ過filtered
4. 4
   濃縮concentrated under reduced pressure
5. 5
   その他The crude material is purified by column chromatography

実験手順

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.

出典