反应详情

In a fashion similar to that described for preparation 15, 2-fluoro-4-bromo-benzoyl chloride oxime (2.00 g, 7.92 mmol), ethyl-2-butynoate (1.33 g, 11.9 mmol), triethylamine (2.2 ml, 15.8 mmol) in diethyl ether (10 ml), and diethyl ether (20 ml) gave 4-ethoxycarbonyl-5-methyl-3-(2-fluoro-4-bromophenyl)isoxazole (2.16 g, 83%) after column chromatography (silica gel, hexanes/diethyl ether gradient). 1H NMR (400 MHz, CDCl3) δ 7.36-7.29 (m, 3H), 4.16 (q, 2H, J=6.8 Hz), 2.70 (s, 3H), 1.15 (t, 3H, J=6.9 Hz)ppm.