反应详情

温度

90 °C

Methyl 4-methyl-3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzoate (compound 5.4, 3.56 g, 12.9 mmol), 5-iodo-2,4-dimethyl-1H-imidazole (compound 5.5, 3.43 g, 15.4 mmol), K2CO3 (5.33 g, 38.6 mmol) and PdCl2(dppf).CH2Cl2 (1.05 g, 1.29 mmol) were added to a round bottom flask. The flask was purged with argon, then dioxane (70 mL) and water (20 mL) were added and the mixture was heated at 90° C. for 16 hours. The mixture was cooled then additional K2CO3 (1M, 25 mL, 25.0 mmol) and catalyst PdCl2(dppf).CH2Cl2 (1.0 g, 1.2 mmol) were added. The mixture was heated at 90° C. for an additional 10 hours, then cooled to room temperature and filtered through Celite®. The solvent was removed under reduced pressure and the residue was cooled to 0° C. and acidified to pH 3-4 with aqueous HCl (2 M). The acidic mixture was washed with EtOAc (150 mL) and then the aqueous material was adjusted to pH 10-11 with aqueous sodium hydroxide (2 M) and extracted with EtOAc (5×200 mL). The combined organic phases were dried (MgSO4), filtered, and concentrated under reduced pressure. The residue was purified by column chromatography (DCM to 5% MeOH in DCM) to yield the title compound as a thick brown oil (2.42 g, 77%). m/z (ES+) 245(M+H)+. 1H NMR (400 MHz, CDCl3) δ 7.89-7.87 (m, 2H), 7.31 (d with fine str, J=8.6 Hz, 1H), 3.89 (s, 3H), 2.38 (s, 3H), 2.31 (s, 3H), 2.11 (s, 3H).

1. customThe flask was purged with argon
2. additiondioxane (70 mL) and water (20 mL) were added
3. temperatureThe mixture was cooled
4. temperatureThe mixture was heated at 90° C. for an additional 10 hours
5. temperaturecooled to room temperature
6. filtrationfiltered through Celite®
7. customThe solvent was removed under reduced pressure
8. temperaturethe residue was cooled to 0° C.
9. washThe acidic mixture was washed with EtOAc (150 mL)
10. extractionextracted with EtOAc (5×200 mL)
11. dry with materialThe combined organic phases were dried (MgSO4)
12. filtrationfiltered
13. concentrationconcentrated under reduced pressure
14. customThe residue was purified by column chromatography (DCM to 5% MeOH in DCM)