反应详情

温度

60 °C

Ethyl 4-(acetyloxy)-3-methyl-1-benzothiophene-6-carboxylate was dissolved in absolute ethanol (500 mL). Potassium carbonate (35 g, 0.25 mol) was added. The reaction mixture was stirred for 3 h at 60° C. and diluted with 200 mL of dichloromethane. The suspension was filtered. The precipitate was washed by 100 mL of dichloromethane. The combined solutions were washed by 200 mL of a 10% aqueous solution of citric acid and evaporated in vacuum to dryness. The obtained crude product was chromatographed on a layer of silica gel (150×100 mm) with hexane/ethyl acetate mixture (2:1) to give the desired product 19.5 g (82 mmol, 60%) as a cream solid. 1H NMR (DMSO-D6): δ ppm 1.35 (t, 3H), 2.60 (s, 3H), 4.20 (qt, 2H), 7.29 (m, 1H), 7.35 (s, 1H), 7.95 (s, 1H); MS (APCI, pos): 237.1.

1. filtrationThe suspension was filtered
2. washThe precipitate was washed by 100 mL of dichloromethane
3. washThe combined solutions were washed by 200 mL of a 10% aqueous solution of citric acid
4. customevaporated in vacuum to dryness
5. customThe obtained crude product
6. customwas chromatographed on a layer of silica gel (150×100 mm) with hexane/ethyl acetate mixture (2:1)