反应详情

Sodium acetate (30 g, 0.36 mol) was added under vigorous stirring to a solution of 3-(ethoxycarbonyl)-4-(5-methyl-2-furyl)but-3-enoic acid (45 g, 0.19 mol) in 250 mL of acetic anhydride. The reaction mixture was refluxed for 2 h and evaporated in vacuum (˜20 mmHg) at 70° C. until the solvent distillation ceased. The obtained crude product was suspended in 500 mL of dichloromethane. The suspension was filtered. The solid was washed with 200 mL of dichloromethane. The combined solutions were washed with 200 mL of a saturated aqueous solution of NaHCO3 and evaporated in vacuum to dryness. The obtained crude product was chromatographed on a layer of silica gel (200×150 mm) with hexane/ethyl acetate mixture, 3:1 as eluent to give 25 g (95 mmol, 51%) of desired compound as a yellow solid.

1. temperatureThe reaction mixture was refluxed for 2 h
2. customevaporated in vacuum (˜20 mmHg) at 70° C. until the solvent distillation
3. customThe obtained crude product
4. filtrationThe suspension was filtered
5. washThe solid was washed with 200 mL of dichloromethane
6. washThe combined solutions were washed with 200 mL of a saturated aqueous solution of NaHCO3
7. customevaporated in vacuum to dryness
8. customThe obtained crude product
9. customwas chromatographed on a layer of silica gel (200×150 mm) with hexane/ethyl acetate mixture, 3:1 as eluent