In this paper, a series of new substituted-5-pyrazolones were first synthesized, then formulated by the Vilsmeier-Haack reaction to obtain substituted-4-carbaldehyde-5-pyrazolones. In the final step, when urea was reacted with formulated pyrazolones, we found that, instead of the C=N bond in azomethine form, the compounds tautomerized to form a series of novel pyrazole-4-ylidenemethylurea structures. The structures of these compounds were elucidated by FTIR, 1H, 13C NMR, LC-MS/MS, and elemental analysis methods. The cytotoxic and antioxidant effects of substituted 5-pyrazolones and their pyrazolone-urea derivatives were investigated in metastatic A431 and noncancerous HaCaT human keratinocytes by a mitochondrial activity test. The effects of the compounds on the migration of cancerous and noncancerous cell lines were investigated by using a cell scratch assay. The General Linear Model, Statistical Package for Social Sciences (SPSS v26) was used to determine if there was a statistically significant difference between the control and the treatment groups. Four of the nine compounds showed an antioxidant effect. All 5-pyrazolone-urea compounds showed higher toxicity (p < 0.05) in cancerous A431 cells compared to noncancerous cells at all time points. All compounds also showed a biphasic hormetic effect. Four of the nine compounds inhibited cell migration.
Keywords: 5-pyrazolone; antioxidant activity; cell proliferation; urea derivatives.