FRAGMENTATION OF ETHYL-1,2,3,4-TETRAHYDROQUINOLINE-2,3-DICARBOXYLIC ACID-DERIVATIVES UPON ELECTRON IONIZATION

The electron ionization-induced fragmentation patterns of -2-phenyl-1H -pyrrolo[3,4-b]quinoline-1,3(2H)-dione derivatives have been studied. It was found that fragmentation starts at the N-phenylsuccinimide ring and its pattern depends on the type and position of the substituents at carbon atoms 5-8. Peaks, which can be assigned to the products of t he retro Diels-Alder opening of the nitrogen atom containing tetrahydr oquinoline ring, were observed.