Design, synthesis, and anticancer evaluation of N4-substituted thiosemicarbazones derived from ortho- and para-ethoxy-benzaldehydes.

Abstract

R₂ - C(S) - NH - N = CH - R₁ [R₁ = o-OCH₂CH₃ & R₂ = C₄H₉N (2-EBP), R₁ = o-OCH₂CH₃ & R₂ = C₄H₉NO (2-EBM), R₁ = p-OCH₂CH₃ & R₂ = C₄H₉N (4-EBP), and R₁ = p-OCH₂CH₃ & R₂ = C₄H₉NO (4-EBM)] have been synthesized. The ligands have been verified via various spectroscopic methods such as IR, NMR, etc. Single-crystal X-ray diffraction methods were applied to identify the structure of 4-EBP. Absorption/emission spectroscopic titration was used to assess the interaction of ligands to calf thymus (CT) DNA. DNA binding studies revealed interactions characterized by hyperchromicity and a slight redshift. 4-EBP showed the highest binding constant (1.58 × 10⁵), indicating that it binds stronger to CT-DNA. The red shift and significant hypochromic shift seen in the fluorescence titration spectra of the BSA binding probes showed the strong interaction of the ligand to BSA. EGFR protein docking investigations verified the potential of the ligands to treat its targets. 4-EBP has the highest docking score (-6.7987 kcal) compared to other synthesized ligands. The B3LYP/6-311 G (d, p) ++ was implemented to calculate density functional theory (DFT). All ligands have a LogP value below 5, indicating lipophilic properties suitable for SwissADME studies. All new ligands follow Lipinski's drug class rules. Low synthetic input levels between 2 and 3 indicate the best results for this material. Each ligand (2-EBP to 4-EBM) has been marked to perform as an oral drug candidate. To test the anticancer potential of four ligands (2-EBP to 4-EBM). 4-EBP showed good efficacy against endothelial and liver cancer cells, with IC₅₀ values of 21.2 ± 0.1 and 45.3 ± 0.1 against MCF-7 and HepG-2 respectively.