反应详情

A solution of (2,3-dioxo-3,4-dihydro-2H-pyrazin-1-yl)-acetic acid ethyl ester (25.0 g, 126 mmol) and phosphorous oxybromide (37.9 g, 132 mmol) in 1,2-dichloroethane (250 mL) was heated to reflux. After 8 h the reaction mixture was treated with sat. aq. Na2CO3 (250 mL) and stirred for 1 h. The mixture was diluted with water (100 mL) and dichloromethane (100 mL), the layers were separated and the aqueous layer was backwashed with EtOAc (3×200 mL). The combined organics were dried (MgSO4), and concentrated to give an oil which was stored on a high vacuum line overnight to afford a brown solid. 1H NMR (CDCl3) δ 7.17 (d, 1H, 4.2 Hz), 7.07 (d, 1H, 4.2 Hz), 4.65 (s, 2H), 4.27 (q, 2H, 7.2 Hz), 1.31 (t, 3H, 7.2 Hz).

1. customthe layers were separated
2. dry with materialThe combined organics were dried (MgSO4)
3. concentrationconcentrated
4. customto give an oil which
5. customwas stored on a high vacuum line overnight
6. customto afford a brown solid