Synthesis Of New Asymmetrical Pyromellitdiimides Derived From Pyromellitic Dianhydride

This work involves the synthesis and characterization of asymmetrical pyromellitdiimide derivatives [IV]a-f by four sequence steps selective reaction . One mole of pyromellitic dianhydride was reacted with one mole of various primary aromatic amines [ 4-nitro aniline , 4-chloro aniline , 4-toludine and 4 -anisidine] in excess of dry acetone to produce six compounds (N-substituted-pyromellitamic monoacid) [I]a-f . These new compounds [I]a-d were converted to the corresponding N- substituted- pyromellitmonoimide [II]a-d via their heating at (80-90) 0C in sodium acetate-acetic anhydride mixture . The compounds [II]a-f were allowed to react with one mole of another primary amines in excess of dry acetone to give new derivatives of amic acid [II]a-d followed by intramolecular cyclization reaction of these compounds [IV]a-f in sodium acetate-acetic anhydride system to yield the desired asymmetrical pyromellitdiimide derivatives [IV]a-f , the above reactions can be summarized in Scheme 1. All the synthesized compounds have been studied and charachterized by their melting points , FTIR , and 1HNMR spectroscopy (for some of them).