Design and synthesis of <i>N</i> -substituted-2-butyl-4-chloro-1 <i>H</i> -imidazole derivatives as potential ACE inhibitors: <i>in vitro</i> study, <i>in-silico</i> analysis, and a multifaceted CSD-supported crystallographic investigation

Imidazole derivatives are prominent in medicinal chemistry because of their vast array of biological effects. They are particularly noteworthy in treating hypertension, as demonstrated by imidazole-based medications such as lisinopril and losartan, which are currently available on the market. In this context, six <i>N</i>-substituted-2-butyl-4-chloro-1<i>H</i>-imidazole derivatives were carefully designed and synthesized through an efficient two-step protocol, with good yields. The synthesized compounds (4a-f) were characterized <i>via</i> various analytical techniques, including FTIR, ¹H NMR, ¹³C NMR, and mass spectrometry. An <i>in vitro</i> assessment of angiotensin-converting enzyme inhibition was conducted. The results showed that compound 4b exhibited an exceptional IC₅₀ value in the micromolar range (1.31 ± 0.026 μM). Additionally, <i>in silico</i> studies were performed, including molecular docking to predict the spatial orientation of the compounds, molecular dynamics simulations to evaluate binding stability with the target protein, and drug likeness studies to ensure adherence to Lipinski's rule. Furthermore, DFT analysis was employed to explore the energy gap of the frontier molecular orbitals (FMOs) and the molecular electrostatic potential (MEP), facilitating the identification of potential nucleophilic and electrophilic attack sites. Comprehensive insights into the molecular structure and packing of compound 4c were obtained through crystallographic studies, Hirshfeld surface analysis, Cambridge Structural Database studies, and energy framework analysis.