反应详情

To a solution of (6-bromo-pyridin-2-yl)-acetic acid (34.0 g, 158.14 mmol) in ethanol (300 ml) was added conc. H2SO4 (5.0 ml) and heated to reflux for 12 h. The reaction mixture was cooled to rt and concentrated under reduced pressure to dryness. Water was added to the residue and the product was extracted with ethyl acetate. Organic layer was washed with brine, dried over anhy. Na2SO4 and concentrated under reduced pressure to furnish the crude product. Column chromatography purification furnished the title compound as a brown liquid. Yield=31.2 g (82%). TLC (20% ethyl acetate in hexane) Rf=0.51; LCMS: RtH7=0.996, [M+1]+=244.0 and 246.0; HPLC: RtH9=3.87 min (97.2%); 1H NMR (400 MHz, CDCl3): δ 7.53 (t, 1H), 7.39 (d, 1H), 7.28 (d, 1H), 4.19 (q, 2H), 3.83 (s, 2H), 1.25 (t, 3H).

1. temperatureheated
2. temperatureto reflux for 12 h
3. concentrationconcentrated under reduced pressure to dryness
4. additionWater was added to the residue
5. extractionthe product was extracted with ethyl acetate
6. washOrganic layer was washed with brine
7. customdried over anhy
8. concentrationNa2SO4 and concentrated under reduced pressure
9. customto furnish the crude product
10. customColumn chromatography purification