反应详情

Heat a solution of 3 g (13.5 mmol) of 7-acetyl-2,3-dihydro-1,4-benzodioxin-2-carboxamide dissolved in 100 cm3 of ethanol saturated with hydrochloric acid at reflux for 18 hours under a nitrogen atmosphere. After cooling, the reaction mixture is filtered, concentrated and, after neutralisation with sodium hydrogen carbonate, extracted with methylene chloride. The crude product obtained by concentrating the organic phase to dryness is purified by chromatography on a silica column (eluant: petroleum ether/diethyl ether, 50:50). Ethyl 7-acetyl-2,3-dihydro-1,4-benzodioxin-2-carboxylate is thereby obtained in a yield of 75%. Melting point: 57° C. ##STR35##

1. temperatureat reflux for 18 hours under a nitrogen atmosphere
2. temperatureAfter cooling
3. filtrationthe reaction mixture is filtered
4. concentrationconcentrated
5. extractionafter neutralisation with sodium hydrogen carbonate, extracted with methylene chloride
6. customThe crude product obtained
7. concentrationby concentrating the organic phase to dryness
8. customis purified by chromatography on a silica column (eluant: petroleum ether/diethyl ether, 50:50)