反应详情

A suspension of ethyl 4-(acetyloxy)-2-ethyl-1-benzofuran-6-carboxylate (8.0 g, 29.0 mmol) and K2CO3 (4.81 g, 34.8 mmol) in ethanol (80 mL) was refluxed for 24 hours. TLC (petroleum ether/EtOAc 4:1) showed complete consumption of the acetate. The solvent was removed under reduced pressure and the residue was poured into water (30 mL). The aqueous phase was acidified to pH˜2 with 10% aqueous HCl (50 mL) and extracted with EtOAc (100 mL×2). The organic layer was dried over Na2SO4 and concentrated. The residue was purified by column chromatography on silica gel eluted with petroleum ether/EtOAc (40:1) to afford the desired compound (6.0 g, 88%) as a yellow solid. 1H NMR (400 MHz, CDCl3): δ 7.87 (s, 1H), 7.45 (s, 1H), 6.46 (s, 1H), 6.36 (s, 1H), 4.34-4.27 (q, 2H), 2.77-2.71 (q, 2H), 1.40-1.31 (t, 3H), 1.31-1.21 (t, 3H).

1. temperaturewas refluxed for 24 hours
2. customconsumption of the acetate
3. customThe solvent was removed under reduced pressure
4. additionthe residue was poured into water (30 mL)
5. extractionextracted with EtOAc (100 mL×2)
6. dry with materialThe organic layer was dried over Na2SO4
7. concentrationconcentrated
8. customThe residue was purified by column chromatography on silica gel
9. washeluted with petroleum ether/EtOAc (40:1)