Synthesis, molecular docking study and antibacterial activity of new pyrazoline derivatives

In this study, a new series of pyrazoline compounds with five members was synthesized by cyclization of chalcone derivatives in presence of phenyl hydrazine (3a-i). The development began with 4-hydroxy acetophenone, which was benzylated via Williamson ether synthesis to give 1-(4-(benzyloxy) phenyl)-3-phenylprop-2-en-1-one (1), many derivatives of chalcones (2a-i) were synthesized by Claisen-Schmidt condensation of the compound (1) with substituted benzaldehyde, chalcones undergo cyclization with phenyl hydrazine to give target pyrazoline derivatives. The structure of all newly obtained compounds was supported by spectral data (FT-IR, 1H-NMR, 13C-NMR and 13C DEPT-135). Some pyrazoline derivatives were estimated for their antibacterial activity against Escherichia coli as Gram-negative and Staphylococcus aureus as Gram-positive. The results showed the high sensitivity of the synthesized compounds to both types of bacteria. Furthermore, this study examines a molecular docking analysis of synthesized compounds, the results revealed a favorable binding contact with the target bacterial DNA gyrase (PDB ID: 1KZN) of E. coli. Finally, combined findings indicate that these compounds exhibit significant antibacterial activity, with computer models suggesting their ability to target bacterial enzymes or receptors, thereby inhibiting their function and suppressing bacterial growth. KEY WORDS: Chalcone, Pyrazoline, Antibacterial activity, Docking study Bull. Chem. Soc. Ethiop. 2025, 39(5), 955-966. DOI: https://dx.doi.org/10.4314/bcse.v39i5.11