反应详情

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.

1. temperatureThe reaction mixture was heated
2. temperatureto reflux for 1 hour
3. concentrationThe mixture was concentrated under reduced pressure
4. dissolutionthe residue was dissolved in water
5. filtrationThe mixture was filtered
6. customto remove tetrakis(triphenylphosphine)palladium
7. extractionthe filtrate was extracted with ethyl acetate
8. customto form
9. customprecipitates
10. dissolutionThe precipitates were dissolved in ethyl acetate
11. dry with materialdried over anhydrous magnesium sulfate
12. filtrationfiltered
13. customto remove the drying agent
14. concentrationconcentrated under reduced pressure