反应详情

Concentrated sulphuric acid (15 ml) was added to 5-chloro-2(2-methoxyvinyl)-benzoic acid (4.43 g) at 0° C. The mixture was stirred for 2 hours, then diluted with ice/water. The product was extracted with ethyl acetate (3×15 ml) and the combined extracts washed with saturated sodium bicarbonate solution. The solution was dried (magnesium sulfate), filtered and concentrated. The residue was purified by flash chromatography (0-5% ethyl acetate/hexane) to afford the sub-title compound as a white solid (3.04 g, 81%). mp 109.8-110.9° C. 1H NMR (400 MHz, CDCl3) δ 6.51(1H, d), 7.28-7.32(1H, m), 7.41(1H, d), 7.64-7.70(1H, m), 8.28(1H, m) ppm.

1. extractionThe product was extracted with ethyl acetate (3×15 ml)
2. washthe combined extracts washed with saturated sodium bicarbonate solution
3. dry with materialThe solution was dried (magnesium sulfate)
4. filtrationfiltered
5. concentrationconcentrated
6. customThe residue was purified by flash chromatography (0-5% ethyl acetate/hexane)