The aim of this study was to synthesize and evaluate the biological activity of pyrazole
derivatives, in particular, to perform a “greener” one-pot synthesis using a solvent-free method as an
alternative strategy for synthesizing hydrazono/diazenyl-pyridine-pyrazole hybrid molecules with
potential anticancer activity. Effective treatment for all types of cancers is still a long way in the future
due to the severe adverse drug reactions and drug resistance associated with current drugs. Therefore,
there is a pressing need to develop safer and more effective anticancer agents. In this context, some hybrid
analogues containing the bioactive pharmacophores viz. pyrazole, pyridine, and diazo scaffolds
were synthesized by one-pot method. Herein, we describe the expedient synthesis of pyrazoles by a onepot
three-component condensation of ethyl acetoacetate/acetylacetone, isoniazid, and arenediazonium
salts under solvent-free conditions, and the evaluation of their cytotoxicity using a sulforhodamine B
assay on three cancer cell lines. Molecular docking studies employing tyrosine kinase were also carried
out to evaluate the binding mode of the pyrazole derivatives under study. 1-(4-Pyridinylcarbonyl)-3-
methyl-4-(2-arylhydrazono)-2-pyrazolin-5-ones and [4-(2-aryldiazenyl)-3,5-dimethyl-1H-pyrazol-1-
yl]-4-pyridinylmethanones, previously described, were prepared using an improved procedure. Among
these ten products, 1-isonicotinoyl-3-methyl-4-[2-(4-nitrophenyl)hydrazono]-2-pyrazolin-5-one (1f)
displayed promising anticancer activity against the MCF-7, HepG2 and HCT-116 cell lines, with an
IC50 value in the range of 0.2-3.4 μM. In summary, our findings suggest that pyrazoles containing hydrazono/
diazenyl and pyridine pharmacophores constitute promising scaffolds for the development of
new anticancer agents.
