N-Phenyl-3,4-dimethylenepyrrolidine

This study involved the preparation and characterization of poly(N-phenyl 3,4-dimethylenepyrrolidine) and the subsequent oxidation and reduction of this polymer. The parent polymer was not very soluble, so it was difficult to characterize. However, after oxidizing in the presence of palladium on carbon in nitrobenzene, the resultant poly(N-phenyl 3,4-dimethylenepyrrole) was soluble in several organic solvents. Attempts to reduce the original polymer to the pyrrolidone were unsuccessful. 

The monodiene, N-phenyl-3,4-dimethylenepyrrolidine, was observed to readily react with dienophiles (i.e. maleic anhydride, maleimides) by the Diels-Alder reaction.17 This 1,3-diene system was extended to prepare novel bis(3,4-dimethyl-enepyrrolidyl) arylenes for polymerization with bismaleimides via the Diels-Alder reaction to afford polyimides without the evolution of volatile byproducts. The bis(3,4-dimethylenepyr-rolidyl) arylenes were prepared by the reaction of 4,4 -dia-minoarylenes with 2,3-dibromomethyl-l,3-butadiene (Scheme 1). 

Diene (VI) was reacted with aniline in methanol in the presence of sodium carbonate to yield N-pheny1-3,4-dimethylenepyrrolidine. However, the purified yield was poor (-20%). The alternate route was a more direct method to prepare the monomer (III) without the side reactions on elimination that could take place in the first synthetic approach. Nevertheless, due to the poor yield, all the monomer (III) used for this work was prepared via the first route. The alternative method does have applicability in the preparation of substituted N-phenyl derivatives as these could be less volatile and more difficult to recover by sublimation. 

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