Water → 4-Benzoyl-5-hydroxybenzocyclobutene-1-carboxylic acid

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Reaction Steps

14 g of 4-benzoyl-5-hydroxybenzocyclobutene-1-carboxylic acid methyl ester are dissolved in 150 ml of ether and the solution is added to 62 ml of 2N aqueous sodium hydroxide solution and 25 ml of water. This mixture is vigorously stirred for 1 hour at room temperature. The ether phase is separated off and extracted once with 75 ml of water. The aqueous phase is washed once with 75 ml of ether. The combined aqueous phases are rendered acidic with 2N aqueous hydrochloric acid and extracted 3 times with 100 ml of methylene chloride each time. The combined methylene chloride extracts are dried over magnesium sulphate and concentrated by evaporation. Crystallisation of the residue from ether/petroleum ether yields 4-benzoyl-5-hydroxybenzocyclobutene-1-carboxylic acid in the form of yellow crystals having a melting point of 167°-169°.

Provenance & Evidence