反应详情

14.2 ml of sulphuric acid (100% strength) are added to a solution of 70.34 g (0.39 mol) of 2-carboxychroman in 1400 ml of methanol and the whole is boiled under reflux for 4 hours. After cooling, the reaction mixture is concentrated by evaporation in vacuo and the residue is dissolved in diethyl ether and washed with water, cold saturated sodium hydrogen carbonate solution and again with water. The ethereal phase is dried over sodium sulphate and concentrated by evaporation in vacuo. 72.8 g (96%) of 2-methoxycarbonylchroman are obtained in the form of a pale yellow oil.

1. temperatureunder reflux for 4 hours
2. temperatureAfter cooling
3. concentrationthe reaction mixture is concentrated by evaporation in vacuo
4. dissolutionthe residue is dissolved in diethyl ether
5. washwashed with water, cold saturated sodium hydrogen carbonate solution and again with water
6. dry with materialThe ethereal phase is dried over sodium sulphate
7. concentrationconcentrated by evaporation in vacuo