4-Aminobenzoic Acid → 4-(2,5-dihydro-2,5-dioxo-1H-pyrrol-1-yl)benzoic acid

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Reaction Steps

N-(para-carboxyphenyl)maleimide was prepared as follows. Maleic anhydride (45.2 grams (g)) was dissolved in from 300-400 milliliters (ml) of acetone. To this solution, an equimolar amount of para-aminobenzoic acid (63.2 g) was added with rapid stirring. The reaction mixture solidified within a few seconds. Excess solvent was removed by evaporation to yield the amic acid intermediate which was then dried overnight at 65° C. under vacuum.

Provenance & Evidence