Sulfuric Acid → (E)-4-(2-(4,5,6,7-Tetrahydro-4,4,7,7-tetramethylbenzo(b)thien-2-yl)-1-propenyl)benzoic acid

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

3.0 g of ethyl p-[2-(4,5,6,7-tetrahydro-4,4,7,7-tetramethylbenzo[b]thien-2-yl)propenyl]benzoate are dissolved in 100 ml of ethanol and the solution is treated with a solution of 3.9 g of potassium hydroxide in 20 ml of water. After stirring at 50° C. for 3 hours, the mixture is cooled, poured into ice-water and acidified with 2N sulphuric acid. The mixture is extracted with ethyl acetate, the organic phase is washed with water, dried over sodium sulphate and evaporated. After recrystallization of the residue from ethyl acetate, there are obtained 2.4 g of p-[(E)-2-(4,5,6,7-tetrahydro-4,4,7,7-tetramethylbenzo[b]thien-2-yl)propenyl]benzoic acid in the form of pale yellowish crystals, m.p. 236°-238° C.

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