反应详情

温度

40 °C

To a solution of (1R,5S)-bicyclo[3.1.0]hexan-2-one (9.19 g, 96 mmol) and diethyl oxalate (12.98 mL, 96 mmol) in absolute ethanol (300 mL) was added a 1.0 M THF solution of potassium tert-butoxide (105 mL, 105 mmol). The resulting yellow solution was stirred at 20° C. for 2 h. (2,4-difluorophenyl)hydrazine hydrochloride (17.26 g, 96 mmol) was added followed by a 3.0 M aqueous solution of hydrogen chloride (96 mL, 287 mmol). The reaction was stirred at 40° C. for 18 h. The volume was reduced by about 200 mL, and then brine (300 mL) was added. The mixture was extracted with dichloromethane (3×250 mL). The combined organic extracts were dried (MgSO4), filtered, and then concentrated. The residue was purified by silica gel flash chromatography to give the title compound as a yellow solid (18.4 g). LCMS m/z=305.3 [M+H]+; 1H NMR (400 MHz, CDCl3) δ ppm 0.49 (td, J=4.8, 3.3 Hz, 1H), 1.16 (td, J=7.8, 5.0 Hz, 1H), 1.38 (t, J=7.1 Hz, 3H), 2.11-2.16 (m, 1H), 2.24-2.30 (m, 1H), 2.90 (d, J=16.6 Hz, 1H), 3.03 (dd, J=16.4, 6.3 Hz, 1H), 4.38 (q, J=7.1 Hz, 2H), 6.97-7.02 (m, 2H), 7.66-7.72 (m, 1H).

1. additionwas added
2. extractionThe mixture was extracted with dichloromethane (3×250 mL)
3. dry with materialThe combined organic extracts were dried (MgSO4)
4. filtrationfiltered
5. concentrationconcentrated
6. customThe residue was purified by silica gel flash chromatography