Catalytic activity of TiO2 nanoparticles in cyclization reactions for pyrazolone formation: DNA binding analysis via spectroscopy, X-ray crystallography, and molecular docking

Abstract

This method of sustainable synthesis utilizes a range of aromatic/heterocyclic aldehydes, phenylhydrazine, and ethyl acetoacetates. The TiO₂ nanoparticle catalyst facilitates cyclization reactions, yielding pyrazolone derivatives with exceptional efficiency (95–97 %) under reflux conditions at 80 °C. The current method achieves high yields of the corresponding cyclo-products in a short reaction time. A variety of physicochemical methods were employed to ascertain the chemical characteristics and structure of the synthesized heterocycles, and the geometrical structure of the well-crystallized compound (Z)-4-((5-bromofuran-2-yl)methylene)-5-methyl-2-phenyl-2,4-dihydro-3H-pyrazol-3-one was characterized by the use of single-crystal X-ray diffraction measurement. The morphology and elemental composition of TiO₂ nanoparticles were examined using SEM/EDX before and after the model reaction. A drop in the Ti (titanium) signal following the reaction indicates surface alterations. The present process provides a new and improved synthesis process for the formation of pyrazolones that is more convenient, well organized in terms of good yields, a simple handling procedure, a short reaction time, and user-friendliness compared to other surviving procedures. One of the synthesized compounds, (Z)-4-((5-bromofuran-2-yl)methylene)-5-methyl-2-phenyl-2,4-dihydro-3H-pyrazol-3-one (2), exhibited significant DNA binding activity. This was further confirmed by a molecular docking study, which revealed a binding energy of −7.2 kcal/mol, and by analyzing the mode of interaction.