Novel 2-Alkoxy-3-Cyanopyridine Derivatives as Cholinesterase Inhibitors: Synthesis, Biological Evaluation, and In Silico Investigations

Alzheimer's disease remains a major challenge in neuroscience and medicine. Cholinesterase inhibitors provide symptomatic relief but do not alter disease progression. While significant progress has been made in understanding its biology, there is an urgent need for effective therapies. In this study, a series of 2-alkoxy-3-cyanopyridine derivatives (1–7) were prepared and evaluated as inhibitors of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). Among the compounds, 3 and 4 were identified as good inhibitors of AChE and BuChE with relatively low IC₅₀ values. 3 inhibited AChE with an IC₅₀ of 53.95 ± 4.29 µM, while 4 had a greater potency for BuChE with an IC₅₀ of 31.79 ± 0.38 µM. Kinetic studies revealed that 3 and 4 are competitive inhibitors with K_i values of 14.23 ± 0.42 and 19.80 ± 3.38 µM for AChE and BuChE, respectively. In silico investigations, including docking studies, DFT calculations, and ADME/drug-likeness properties, were carried out to understand the mode of interaction of 3 and 4 toward the AChE and BuChE enzymes, as well as to determine their molecular geometry, chemical reactivity, and pharmacokinetic properties. This study highlights the potential of 3-cyanopyridine derivatives in the treatment of AD and provides a solid foundation for further optimization and exploration of their therapeutic applications.