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