Hydrochloric Acid → 4-oxo-3,4-dihydro-2H-1-benzopyran-2-carboxylic acid

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Reaction Steps

A solution of 3-(2-hydroxybenzoyl)acrylic acid (3.02 g) in aqueous sodium carbonate (5%, 55 ml) was stirred at room temperature for 15 hours, acidified with 2N HCl and extracted with ethyl acetate. The ethyl acetate layer was washed with water, dried (MgSO4) and then treated with activated charcoal, after which the solvent was distilled off, to yield 2,3-dihydro-4-oxo-4H-1-benzopyran-2-carboxylic acid (2.01 g, 67%), which was then recrystallized from ethyl acetate-hexane to yield colorless prisms having a melting point of 170° to 171° C.

Provenance & Evidence