反应详情

温度

-78 °C

To a stirred solution of 5-iodo-2,4-dimethylbenzoic acid (compound 1.3, 5.00 g, 18.1 mmol) in tetrahydrofuran (150 mL) under nitrogen at −78° C. was added n-BuLi (2.5 M in THF, 18 mL, 45 mmol) drop-wise. The mixture was stirred at −78° C. for 1 h and then DMF (5.3 mL, 68 mmol) was added drop-wise. The resulting mixture was stirred at −78° C. for 0.5 h and then carefully quenched by slow addition of water (50 mL). The pH of the mixture was adjusted to ˜3-4 with aqueous HCl (6 M) and then extracted with ethyl acetate (3×200 mL). The combined organic layers were dried (Na2SO4), filtered, and concentrated under reduced pressure. The residue was purified using silica gel column chromatography with ethyl acetate/petroleum ether (1:10-1:5) as the eluent to yield the title compound as a white solid (2.4 g, 74%).

1. stirringThe resulting mixture was stirred at −78° C. for 0.5 h
2. customcarefully quenched by slow addition of water (50 mL)
3. extractionextracted with ethyl acetate (3×200 mL)
4. dry with materialThe combined organic layers were dried (Na2SO4)
5. filtrationfiltered
6. concentrationconcentrated under reduced pressure
7. customThe residue was purified