反应详情

温度

25 °C

(E)-4-Oxo-but-2-enoic acid ethyl ester (4.60 mL, 38.32 mmol), 2-nitrobenzoic acid (1.08 g, 6.39 mmol), and pyrrolidine (0.53 mL, 6.39 mmol) were added simultaneously to a solution of commercially available 2-chloro-6-hydroxy-benzaldehyde (5.0 g, 31.93 mmol) in dimethysulfoxide (30 mL) at 25° C. and the solution was stirred for 78 hours at 25° C. The reaction was quenched by the addition of water. The reaction mixture was then partitioned between water and ethyl acetate. The combined organics were washed with a saturated brine solution, dried over anhydrous sodium sulfate, filtered, rinsed and concentrated in vacuo. The residue obtained was purified on a silica gel Flash column chromatography using ethyl acetate-hexanes (1:1.2) as eluents, yielding 5-chloro-3-formyl-2H-chromene-2-carboxylic acid ethyl ester as a solid (2.08 g, 49.5%).

1. customThe reaction was quenched by the addition of water
2. customThe reaction mixture was then partitioned between water and ethyl acetate
3. washThe combined organics were washed with a saturated brine solution
4. dry with materialdried over anhydrous sodium sulfate
5. filtrationfiltered
6. washrinsed
7. concentrationconcentrated in vacuo
8. customThe residue obtained
9. customwas purified on a silica gel Flash column chromatography