反应详情

温度

130 °C

2,4,6-Trimethylpyridine (1.6 mL) was added dropwise into 136a (2.32 g, 8.0 mmol) in phosphorus oxychloride (3.2 mL) at 0° C. The reaction mixture was heated at 130° C. for 20 h. The reaction was stopped at ˜70% conversion as determined by HPLC. The dark brown solution was poured into water (40 mL) with stirring, and stirred for 15 min. The brown precipitate was filtered, air dried, and purified by SiO2 chromatography (120 g), loaded with a CH2Cl2 and eluted using a gradient of ethyl acetate in hexanes to afford 136b (1.91 g, 77% yield) as an amber colored oil; HPLC purity 100%, 3.95 min (Method A); 1H NMR (500 MHz, CDCl3) δ ppm 8.36 (d, 1H, J, J=10.0 Hz), 7.47 (d, 1H, J=5.0 Hz), 7.23 (m, 2H), 7.16 (d, 1H, J=10.0 Hz), 6.95 (d, 1H, J=10.0 Hz), 1.36 (s, 9H); 13C (125 MHz, CDCl3) δ (ppm), 155.30, 153.23, 150.87, 141.45, 137.72, 133.22, 127.59, 126.91, 125.79, 123.04, 118.39, 34.60, 30.25.

1. stirringstirred for 15 min
2. filtrationThe brown precipitate was filtered
3. customair dried
4. custompurified by SiO2 chromatography (120 g)
5. washeluted