Synthesis and characterization of azomethine bismaleimide derivatives

This thesis is concerned with the synthesis of bismaleimide compounds containingazomethine linkages. The reaction of aryl amines, such as 1,4-phylenediamine with p-nitrobenzaldehyde to obtain Schiff bases containing double imine bonds was investigated. Thepurification of the products obtained from this reaction, proved to be problematic due to the very1low solubility in common organic solvents. These products could not be characterized H NMRunambiguously. Therefore this approach was abandoned and different route was projected.This new approach involved in the protection of the carbonyl group of p-nitrobenzaldehyde with ethylene glycol as acetal and then followed reduction of nitro function toamine of 2-p-nitrophenyl-1,3 dioxalane. The imizidation of the resultant amine is followed by theformation of imine linkages to produce the Schiff bases. Various reduction methods wereprobed to reduce the nitro group selectively without affecting the protected acetal in themolecule. This transformation could not be achieved under the conditions investigated.1Previous synthesis of the isomeric bismaleimide was also studied. IR and H NMRexperiments were used for identification of these products.Key words: Aromatic nitro compounds, azomethine linkage, bismaleimides, reduction of nitrocompounds, Schiff bases