Synthesis, X-Ray, Spectroscopic Characterization, Hirshfeld Surface Analysis, Molecular Docking, and DFT Calculations of a New Series of 3-Hydrazono and 3-Phenylhydrazono Isatin Derivatives

Two novel N-alkylated isatin derivatives (2–3) were synthesized under phase-transfer catalysis conditions. Their condensation with hydrazine hydrate and phenylhydrazine in refluxing ethanol as solvent generates two series of isatin derivatives (3-hydrazono and 3-phenylhydrazono) (4–7). The structures synthesized are elucidated using UV/Vis, FTIR, ¹³C-NMR, ¹H-NMR, and single crystal X-ray diffraction techniques of 2, 3, and 5. The experimental data were compared with the predicted ones obtained at the B3LYP/6-31G(d,p) level of theory. Relatively, good agreements were found between the calculated and experimental results. The intermolecular contacts in 2, 3, and 5 were investigated through the Hirshfeld surface analysis. The expected inhibitory efficiency of 2, 3, and 5 against cyclooxygenase-2 (COX-2) are investigated by their molecular docking into the binding site of COX-2, which revealed that 2 might have strong inhibition efficacy against COX-2 compared to 3.