反应详情

温度

0 °C

HCl gas was bubbled through a solution of methyl 4-formylbenzoate (8.20 g, 50.0 mmol) and 2,3-butanedione 2-oxime (5.05 g, 50 mmol) in HOAc (25 mL) at 0° C. and the mixture was stirred at 0° C. for 30 min. The mixture was diluted with Et2O (300 mL) and the resulting precipitate was filtered, washed with Et2O (50 mL) and dried in vacuo to give N-oxide 1 (12.05 g, 97%) as a white powder: mp (Et2O) 127-128° C.; 1H NMR (CDCl3) δ 8.44 (br d, J=8.8 Hz, 2H, H-2, H-6), 8.23 (br d, J=8.8 Hz, 2H, H-3, H-5), 3.98 (s, 3H, OCH3), 2.50 (s, 2H, CH3), 2.47 (s, 3H, CH3); MS m/z 248.6 (MH+, 100%).

1. filtrationthe resulting precipitate was filtered
2. washwashed with Et2O (50 mL)
3. customdried in vacuo