反应详情

To a −78° C. solution of 1-chloro-3,5-difluoro-benzene (5.0 g, 34 mmol) in THF (70 mL) at was added n-butyl lithium (1.6 M in hexane, 19 mL). After 50 min, DMF (5.2 mL, 67 mmol) was added and the reaction was allowed to warm to rt over 18 h. After the addition of 0.5 M HCl (150 mL) and ether (150 mL), the aqueous layer was extracted with Et2O (3×). The combined organic extracts were dried and concentrated to provide a yellow solid. The crude material was dissolved in warm hexanes and a small amount of white solid formed upon cooling. This white solid was filtered off and discarded. The filtrate was concentrated to provide the title compound as a light yellow solid (2.5 g, 41%). 1H NMR (CDCl3): 10.3 (s, 1H), 7.06 (d, J=8.1 Hz, 2H).

1. extractionthe aqueous layer was extracted with Et2O (3×)
2. customThe combined organic extracts were dried
3. concentrationconcentrated
4. customto provide a yellow solid
5. customa small amount of white solid formed
6. temperatureupon cooling
7. filtrationThis white solid was filtered off
8. concentrationThe filtrate was concentrated