Synthesis and Polarographic Behavior of 2H-Isoindole-4,7-diones

Article abstract of DOI:10.1007/BF00823429

2-Phenylthio-1,4-benzoquinone (1a) reacts with azomethine ylide AY-A to give 2-methyl-5-phenylthio-2H-isoindole-4,7-dione (4f).With 2-(N-methylanilino)-5-methyl-1,4-benzoquinone (1b), the azomethine ylide AY-B undergoes cycloaddition to yield an inseparable mixture of 5a-methyl-8-(N-methylanilino)-2,3,5,5a,9a,9b-hexahydro-pyrrolo<2,1-a>-1H-isoindole-6,9-dione (5 bI) and 9a-methyl-7-(N-methylanilino)-2,3,5,5a,9a,9b-hexahydropyrrolo<2,1-a>-1H-isoindole-6,9-dione (5 bII).The structures of 5 bI and 5 bII were established on basis of two-dimensional-NMR-techniques.The mechanism of the cycloaddition of azomethine ylides to 1,4-quinones was studied on basis of cyclovoltammetric investigations.To determine the electron affinity of the isoindoledione derivatives 4 a-f and 5 a-b the peak potentials were measured by differential pulse polarography (DPP). Keywords. 1,3-Dipolar cycloaddition; Isoindoledione derivatives; 2 D-NMR; Cyclovoltammetry; DPP.