反応 #657325

反応方程式

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

tert-butyl [4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridin-2-yl]carbamate

Tert-butyl [4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridin-2-yl]carbamate

sodium carbonate

→

4-(2-phenylpyrazolo[1,5-a]pyrimidin-3-yl)pyridin-2-amine

収率 45.8%

溶媒

1,4-dioxan

water

反応条件

後処理

1. 1
   その他The reaction mixture is flushed with argon for 5 mins
2. 2
   その他sealed
3. 3
   温度the mixture is heated for 2 h at 120° C
4. 4
   抽出extracted with ethyl acetate (3×50 mL)
5. 5
   乾燥The organic layer is dried over anhydrous magnesium sulphate
6. 6
   ろ過filtered
7. 7
   濃縮concentrated under reduced pressure
8. 8
   その他The crude material is purified by column chromatography

実験手順

3-Bromo-2-phenylpyrazolo[1,5-a]pyrimidine (1.0 g, 3.65 mmol) and tert-butyl [4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridin-2-yl]carbamate (1.29 g, 4.01 mmol, 1.1 eq) are dissolved in 10 mL 1,4-dioxan. To this mixture bis(tricyclohexylphosphine)palladium(II)-dichloride (269 mg, 0.37 mmol, 0.1 eq) and 9.1 mL sodium carbonate solution (2 molar) are added. The reaction mixture is flushed with argon for 5 mins and then sealed. Next the mixture is heated for 90 min at 120° C. in the microwave (Biotage). Tert-butyl [4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridin-2-yl]carbamate (214 mg, 1.4 mmol, 0.37 eq) and bis(tricyclohexylphosphine)palladium(II)-dichloride (269 mg, 0.37 mmol, 0.1 eq) are then added and the mixture is heated for 2 h at 120° C. The reaction mixture is then poured in water and extracted with ethyl acetate (3×50 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 heptane and ethyl acetate (1:0 to 1:1) as eluent and 0.48 g (44%) of 4-(2-phenylpyrazolo[1,5-a]pyrimidin-3-yl)pyridin-2-amine are obtained as a white solid.

出典