The Study of Liquid Crystal Phases and the Bacterial Efficacy of New Derivatives of the Heterocyclic Tetrazole Ring

This study includes the preparation of a five‐ring tetrazole precursor from hydrazones derived from diethyl terephthalate as a nucleus in its preparation. Tetrazoles were prepared from the reaction of prepared hydrazones with sodium azide in a 2:1 molar ratio in the presence of THF as a solvent. Using physical and spectroscopic methods such as UV, IR, and proton and carbon nuclear magnetic resonance spectroscopy ( 1 H, 13 C‐NMR) to confirm the correct structure of the prepared compounds and determine their solubility and purity using thin layer chromatography (TLC) The progress of the reaction was followed and the bioavailability was evaluated using two bacterial isolates known for their resistance to antibiotics: Gram‐negative Escherichia coli (Gram‐ve) and Gram‐positive Escherichia coli . Staphylococcus aureus (Gram+ve), and in comparison with the antibiotics used as control agents: ciprofloxacin, the results showed good inhibitory activity against both types of bacteria used, with high efficacy and selectivity. The liquid crystalline phase of some of the prepared compounds (S 11 ) was examined using a polarizing microscope equipped with a POM electric heater, and it was observed that the resulting transformation was only unidirectional during heating and did not appear during the cooling stage. They also exhibit a crystalline character with different properties, depending on the nature of the generating units of each molecule.