Sulfuric Acid → 2-Hydroxy-3,5-dimethyl-2-cyclopenten-1-one

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Reaction Steps

85.1 g (0.5 mol) of the acid obtained according to paragraph (c), namely 2-carboxy-2,4-dimethylcyclopent-4-en-5-olone, are treated with 851 of 10% sulphuric acid and the mixture is refluxed for 45 minutes. For the working-up, the mixture is adjusted to pH 7 with 2 N sodium hydroxide solution and then extracted three times with methylene chloride. The combined organic phases are dried over sodium sulphate and dried in a high vacuum for 1 hour. There are obtained 57.4 g (91%) of crystalline 3,5-dimethylcyclopent-2-en-2-olone of melting point 93°-94° C. The product is identical with the product obtained according to paragraph (c) of Example 4.

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