反应详情

2-(2-Methoxy-3-nitro-phenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane 6a (1.7 g, 6.08 mmol), 2-bromo-5-methyl-thiazole-4-carboxylic acid (900 mg, 4.05 mmol), tetrakis(triphenylphosphine)palladium (233 mg, 0.2 mmol) and sodium carbonate (1.29 g, 12.16 mmol) were dissolved in 30 mL of 1,4-dioxane. The reaction mixture was heated to reflux for 4 hours. The reaction was monitored by TLC until the disappearance of the starting materials. The mixture was filtered and the filtrate was concentrated under reduced pressure. The residue was diluted with 20 mL of hydrochloric acid (1 N) and 30 mL of ethyl acetate. The separated organic layer was washed with saturated brine, dried over anhydrous sodium sulfate, filtered to remove the drying agent and concentrated under reduced pressure. The residue was recrystallized from a solvent mixture of ethyl acetate and hexane to obtain the title compound 2-(2-methoxy-3-nitro-phenyl)-5-methyl-thiazole-4-carboxylic acid 47a (310 mg, yield 26%) as a yellow solid.

1. temperatureThe reaction mixture was heated
2. temperatureto reflux for 4 hours
3. filtrationThe mixture was filtered
4. concentrationthe filtrate was concentrated under reduced pressure
5. additionThe residue was diluted with 20 mL of hydrochloric acid (1 N) and 30 mL of ethyl acetate
6. washThe separated organic layer was washed with saturated brine
7. dry with materialdried over anhydrous sodium sulfate
8. filtrationfiltered
9. customto remove the drying agent
10. concentrationconcentrated under reduced pressure
11. customThe residue was recrystallized from a solvent mixture of ethyl acetate and hexane