Investigation of the mass-spectrometric fragmentation of some isoindole derivatives

Pyrido- and pyrimidoisoindoles: methods of synthesis and properties

“…1 1. Synthesis of pyrido[2,1-a]isoindole derivatives a. Closure of the pyrrole ring with formation of the N(5)7C (6) bond The closure of the pyrrole ring with the concomitant formation of the N(5)7C (6) bond is one of the general approaches to the synthesis of aromatic isoindole systems. There are only a few examples of the synthesis of pyrido[2,1-a]isoindoles prepared by this method.…”

“…E-mail: palek@mail.univ.kiev.ua (A A Pokholenko), z_voitenko@mail.univ.kiev.ua (Z V Voitenko), vkovtunenko@mail.univ.kiev.ua (V A Kovtunenko) A heptacyclic heteroaromatic system with a junction nitrogen atom containing a pyrido[2,1-a]isoindole fragment has been synthesised. 10 Upon thermal decarboxylation of quinaldinic acid (6) in the presence of meso-benzanthrone (7), the intermediate 2-(7-hydroxy-7-benzanthryl)quinoline (8) eliminates a water molecule and cyclises into compound 9.…”

“…In this case, the formation of the N(5)7C (6) bond is preceded by the formation of the C(10a)7C(10b) bond, which results in the closure of the pyrrole ring and the formation of a fused pyrido[2,1-a]isoindole system. b. Closure of the pyrrole ring with formation of the C(10a)7C(10b) bond The most popular procedures for the synthesis of the pyridoisoindole system are based on the use of readily available N-substituted pyridine derivatives as the starting compounds.…”

“…The mass-spectrometric behaviour of some fused isoindole derivatives has been described. 6 Studies of the fragmentation patterns of molecular ions of pyrido[2,1-a]-and pyrimido[2,1-a]isoindoles suggest their aromaticity. The specific pathways of their fragmentation under electron impact have been studied.…”

“…4,5 This concept was confirmed experimentally for isoindole derivatives using X-ray diffraction analysis 4 and mass spectrometry. 6 The present review is devoted to the methods of synthesis and chemical properties of three types of isoindole systems fused at the pyrrole ring and containing a junction nitrogen atom, viz., pyrido[2,1-a]-(1), { pyrimido[2,1-a]- (2) and pyrimido[6,1-a]isoindole (3) derivatives.…”