Reaction of aroylpyruvic acids methyl esters with 4-aminobenzoic acid. Antioxidant activity of the obtained compounds

4-{[(2Z)-4-Aryl-2-hydroxy-4-oxobut-2-enoyl]amino}benzoic acids were synthesized by reacting methyl esters of aroylpyruvic acids with 4-aminobenzoic (p-aminobenzoic) acid in glacial acetic acid in the presence of anhydrous sodium acetate. 4-{[(2Z)-4-Aryl-1-methoxy-1,4-dioxobut-2-en-2-yl)]amino}benzoic acids were synthesized by reacting the above reagents in a mixture of glacial acetic acid–ethanol (1:1) without adding anhydrous sodium acetate. Structure of the obtained compounds was confirmed by 1H and 13C{1H} NMR and IR spectroscopy. The antioxidant activity of the synthesized compounds was studied.