Novel Schiff Bases Derived From Pyromellitic Dianhydride

Abstract

The new Schiff bases derived from pyromelliticdianhydride were synthesized by several steps reaction . A symmetrical diamicacide [I ]a-c were synthesized by the reaction of pyromelliticdianhydride with some aromatic amines (containing electron withdrawing , repulling groups ) in dry acetone. In the second step the diacids were converted to their corresponding diimide [II ]a-c using acetic anhydride and sodium acetate system as a dehydrating agent, via the intra molecular cyclization steps of amic acids. The third step was to synthesize the hydrazone derivatives from the reaction of diimides , with 80 % hydrazine hydrate at (50-60)C˚ . These hydrazone derivatives were allowed to react with several aromatic aldehydes to form new Schiff bases via step four at a temperature near by (50)C˚ . All the novel compounds and their structures have been ascertained by their melting points , mixed melting points , C .H . N analysis , FTIR spectroscopy and HNMR for some of them .