反应详情

温度

50 °C

4.0 g of ethyl p-[(E)-2-(4,4-dimethyl-6-chromanyl)-propenyl]benzoate were dissolved in 80 ml of ethanol and the solution obtained was treated with a solution of 5.6 g of potassium hydroxide in 20 ml of water and 20 ml of ethanol. After stirring at 50° C. for 3 hours, the mixture was cooled, poured into ice/water, acidified with 2N sulphuric acid and extracted repeatedly with ethyl acetate. The organic phase was washed with water, dried over sodium sulphate and evaporated. After recrystallization of the residue from methylene chloride/hexane, there was obtained 3.4 g of p-[(E)-2-(3,4-dihydro-4,4-dimethyl-2H-1-benzopyran-6-yl)propenyl]benzoic acid in the form of colorless crystals of melting point 196°-197° C.

1. customthe solution obtained
2. temperaturethe mixture was cooled
3. extractionextracted repeatedly with ethyl acetate
4. washThe organic phase was washed with water
5. dry with materialdried over sodium sulphate
6. customevaporated
7. customAfter recrystallization of the residue from methylene chloride/hexane