Abstract Reactions of alkyl 4-aminobenzoates with maleic anhydride give the corresponding alkyl 4-(2, 5-dioxo-2, 5-dihydro-1 H-pyrrol-1-yl) benzoates, and the latter are converted into 4- (3-dialkylamino-2, 5-dioxo-2, 3, 4, 5-tetrahydro-1 H-pyrrol-1-yl) benzoates by treatment with secondary amines.