反应详情

A solution of 2-(1-ethoxy-ethenyl)-5-fluoro-6-methyl-pyridine obtained from Step A (15.3 g) in THF (200 mL) and water (8 mL) was treated with N-bromosuccinimide (12.02 g) at room temperature. After stirring for 10 min, the reaction was concentrated in vacuo. The resulting residue was purified by silica gel chromatography (eluted with a gradient of ethyl acetate in hexanes) to give 2-bromoacetyl-5-fluoro-6-methyl-pyridine, together with an unidentified impurity. This product was used in the next step. 1H NMR (500 MHz, CDCl3): δ 7.98 (dd, 1H), 7.44 (t, 1H), 4.83 (s, 2H), 2.57 (d, 3H).

1. concentrationthe reaction was concentrated in vacuo
2. customThe resulting residue was purified by silica gel chromatography (
3. washeluted with a gradient of ethyl acetate in hexanes)