反应详情

温度

110 °C

Under an argon atmosphere, to a solution of 2-(5-amino-6-benzyl-3-chloropyrazin-2-yl)-5-methoxybenzaldehyde (7) (2.28 g, 6.44 mmol) in deaerated toluene (30 mL) were successively added dichlorobis(triphenylphosphine)palladium(II) (226 mg, 322 mol), tributyl(vinyl)tin (3.75 mL, 12.8 mmol) and tetra-n-butylammonium chloride (3.50 g, 12.6 mmol) at room temperature. The mixture was heated to reflux for 1.5 hours (oil bath temperature at 110° C.). After cooling to room temperature, to the mixture was added water and the product was extracted with ethyl acetate (×3). The combined organic extract was washed successively with water (×1) and brine (×1) followed by drying over anhydrous sodium sulfate. After filtration and concentration under reduced pressure, the residue was purified by silica gel flash column chromatography (silica gel mixed with 10 wt % potassium fluoride, n-hexane/ethyl acetate=3/1) to give 2-(5-amino-6-benzyl-3-vinylpyrazin-2-yl)-5-methoxybenzaldehyde (8) (1.24 g, 3.59 mmol, 55.5%) as a reddish brown oily substance. TLC Rf=0.27 (n-hexane/ethyl acetate=3/1); 1H NMR (500 MHz, CDCl3) δ 3.92 (s, 3H), 4.15 (s, 2H), 4.50 (s, 2H), 5.39 (dd, 1H, J=2.0, 11.0 Hz), 6.33 (dd, 1H, J=2.0, 17.0 Hz), 6.57 (dd, 1H, J=11.0, 17.0 Hz), 7.20-7.28 (m, 4H), 7.30-7.36 (m, 2H), 7.41 (d, 1H, J=8.5 Hz), 7.55 (d, 1H, J=3.0 Hz), 9.88 (s, 1H); 13C NMR (126 MHz, CDCl3) δ 41.0, 55.7, 110.6, 120.5, 121.0, 127.2, 128.5 (2C), 129.1 (2C), 132.3, 132.9, 134.4, 136.1, 136.5, 138.7, 140.2, 145.2, 151.5, 159.8, 191.5.

1. customat room temperature
2. temperatureThe mixture was heated
3. temperatureAfter cooling to room temperature, to the mixture
4. extractionthe product was extracted with ethyl acetate (×3)
5. extractionThe combined organic extract
6. washwas washed successively with water (×1) and brine (×1)
7. dry with materialby drying over anhydrous sodium sulfate
8. filtrationAfter filtration and concentration under reduced pressure
9. customthe residue was purified by silica gel flash column chromatography (silica gel mixed with 10 wt % potassium fluoride, n-hexane/ethyl acetate=3/1)