Sulfuric Acid → 2-Carboxy-2,4-dimethylcyclopent-4-en-5-olone

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Reaction Steps

4.8 g (24 mmol) of the foregoing 2-carboethoxy-2,4-dimethylcyclopent-4-en-5-olone are treated with 48 ml of 2 N sodium hydroxide solution and the mixture is stirred at room temperature for 1.5 hours. For the working-up, the mixture is adjusted to pH 3 with 10% sulphuric acid and extracted three times with ethyl acetate. The combined organic phases are dried over sodium sulphate, concentrated and dried in a high vacuum for 2 hours. There are obtained 3 g (58.5%) of 2-carboxy-2,4-dimethylcyclopent-4-en-5-olone of melting point 98°-105° C., with elimination of carbon dioxide.

Provenance & Evidence