反応 #471524

反応方程式

2-(2-Methoxy-5-methyl-3-nitro-phenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane

2-(2-methoxy-5-methyl-3-nitro-phenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane

5-bromothiophene-2-carboxylic acid

sodium carbonate

→

5-(3-nitro-2-methoxy-5-methyl-phenyl)thiophene-2-carboxylic acid

収率 73.6%

溶媒

1,4-dioxane

water

反応条件

後処理

1. 1
   温度The reaction mixture was heated
2. 2
   温度to reflux for 1 hour
3. 3
   濃縮The mixture was concentrated under reduced pressure
4. 4
   workup.DISSOLUTIONthe residue was dissolved in water
5. 5
   ろ過The mixture was filtered
6. 6
   その他to remove tetrakis(triphenylphosphine)palladium
7. 7
   抽出the filtrate was extracted with ethyl acetate
8. 8
   その他to form
9. 9
   その他precipitates
10. 10
    workup.DISSOLUTIONThe precipitates were dissolved in ethyl acetate
11. 11
    乾燥dried over anhydrous magnesium sulfate
12. 12
    ろ過filtered
13. 13
    その他to remove the drying agent
14. 14
    濃縮concentrated under reduced pressure

実験手順

2-(2-Methoxy-5-methyl-3-nitro-phenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane 24a (4.0 g, 14.5 mmol), 5-bromothiophene-2-carboxylic acid (1.0 g, 4.8 mmol), tetrakis(triphenylphosphine)palladium (0.276 g, 0.24 mmol) and sodium carbonate (1.01 g, 9.6 mmol) were dissolved in 30 mL of 1,4-dioxane and 10 mL of water. The reaction mixture was heated to reflux for 1 hour. The reaction was monitored by TLC until the disappearance of the starting materials. The mixture was concentrated under reduced pressure and the residue was dissolved in water. The mixture was filtered to remove tetrakis(triphenylphosphine)palladium and the filtrate was extracted with ethyl acetate. The aqueous layer was acidified to form precipitates. The precipitates were dissolved in ethyl acetate, dried over anhydrous magnesium sulfate, filtered to remove the drying agent and concentrated under reduced pressure to obtain the title compound 5-(3-nitro-2-methoxy-5-methyl-phenyl)thiophene-2-carboxylic acid 24b (1.03 g, 73.6%) as a yellow solid.

出典