Phenylacetic Acid → 1,3-Dihydro-3-oxo-5-isobenzofurancarboxylic acid

Participants

Reaction Steps

By this method (schematically shown above) a 2-, 3- or 4- substituted phenylacetic acid (I) is reacted with benzene 1,2,4-tri-carboxylic anhydride (II) in about equimolar amounts at a temperature of about 200° to 280° C. in the presence of a suitable catalyst such as potassium acetate, sodium acetate or the sodium or potassium salt of the phenylacetic acid used. This results in a mixture of 3-(2-, 3- or 4-substituted benzylidene) phthalide-6-carboxylic acid (IIIa) and -5-carboxylic acid (IIIb).

Provenance & Evidence