Water → 3-Benzoyl-2,4-dihydroxyquinoline-5-carboxylic acid

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Reaction Steps

To 0.6 grams of methyl 3-benzoyl-4-hydroxy-2-quinolone-5-carboxylate are added 1.5 grams of sodium hydroxide, 30 ml of water and 30 ml of dimethyl sulfoxide, the mixture is heated at 100° to 120° C. for three hours with stirring, cooled, acidified and diluted hydrochloric acid, and crystals separated out therefrom are collected by filtration to give 0.54 grams of 3-benzoyl-4-hydroxy-2-quinolone-5-carboxylic acid, colorless powder, melting at above 300° C.

Provenance & Evidence