The synthesis and characterization of new schiff bases: 4-[(Pyridin-4-ylmethylene) amino] phenylalkanoates

Four new heterocyclic Schiff bases were synthesized from the reaction between 4-[(pyridin-4-ylmethylene)amino]phenol and fatty acids with even number alkyl chains ranging from twelve to eighteen carbons. Their structures were elucidated using spectroscopic techniques such as FT-IR, EIMS and NMR. Phase-transition temperatures and the thermal parameters were obtained from differential scanning calorimetry (DSC). The texture observation was carried out with a polarizing optical microscope (POM) over heating and cooling cycles. All of the title compounds exhibited direct isotropization process.