反应详情

n-Butyllithium (1.6M in hexanes, 127 mL, 203 mmol) was added dropwise to a stirred, cooled (−10° C.) solution of 4-chloro-N-(4-chloro-2-methylphenyl)benzamide (Description 27, 27.1 g, 97 mmol) in tetrahydrofuran (600 mL). The mixture was allowed to warm to room temperature and stirred overnight. The mixture was cooled to 0° C. and further n-butyllithium (1.6M in hexanes, 30 mL, 483 mmol) was added dropwise. The mixture was stirred at room temperature for 2 h., then hydrochloric acid (2.5M, 200 mL) was added. The mixture was stirred at room temperature overnight, then extracted with ethyl acetate. The combined organic fractions were dried (MgSO4) and the solvent was evaporated under reduced pressure. The residue was purified by flash column chromatography on silica gel, eluting with isohexane/EtOAc (85:15), to give the title compound (3.6 g, 14%). 1H NMR (360 MHz, CDCl3) δ 8.30 (1H, br s), 7.57 (3H, m), 7.42 (2H, d, J 9.1 Hz), 7.30 (1H, d, J 8.6 Hz), 7.15 (1H, dd, J 8.6, 2.0 Hz) and 6.74 (1H, s).

1. temperatureThe mixture was cooled to 0° C.
2. stirringThe mixture was stirred at room temperature for 2 h.
3. stirringThe mixture was stirred at room temperature overnight
4. extractionextracted with ethyl acetate
5. dry with materialThe combined organic fractions were dried (MgSO4)
6. customthe solvent was evaporated under reduced pressure
7. customThe residue was purified by flash column chromatography on silica gel
8. washeluting with isohexane/EtOAc (85:15)