Design and synthesis of novel pyrazoline derivatives for their spectroscopic, single crystal X-ray and biological studies

Abstract

N-Acyl-2-pyrazolines have been synthesized via cyclization of chalcones with hydrazine hydrate in the presence of aliphatic acids. These pyrazolines (2a–c) were obtained in good yield (up to 84%), and the used method was found to be efficient for the preparation of pyrazolines. The structures were determined by FT-IR and NMR spectroscopic techniques and further confirmed by crystallographic diffraction study for a compound 2a. Single crystal diffraction studies help to find the intermolecular interactions which were endorsed by the Hirshfeld surface analysis. Furthermore, Hirshfeld analysis describe the different intermolecular contacts, among these H…H is the major contributor. The synthesized pyrazolines were determined for their efficacy against bacterial strains. The compound 2b displayed most promising antimicrobial activity against both Gram-positive and Gram-negative bacterial strains. The minimum inhibitory concentration (MIC) observed was 32 µg/mL against Staphylococcus aureus, Escherichia coli, and 64 µg/mL against Streptococcus pyogenes, S. typhimurium pathogens. The compounds (2a–c) were also explored for their inhibitory potential against a known therapeutic target and an essential bacterial enzyme, DNA gyrase, using computational methods.