Synthesis of new donepezil analogues and investigation of their effects on cholinesterase enzymes.

Donepezil (DNP), an acetylcholinesterase (AChE) inhibitor, is one of the most preferred choices in Alzheimer diseases (AD) therapy. In the present study, 38 new DNP analogues were synthesized. Structures of the synthesized compounds (1-38) were elucidated by IR, 1H NMR, 13C NMR and HRMS spectroscopic methods and elemental analysis. Inhibitory potential of the compounds on cholinesterase enzymes was investigated. None of the compounds displayed significant activity on butyrylcholinesterase (BChE) enzyme. On the other hand, compounds 26-29 indicated important inhibitory activity on AChE enzyme. Kinetic studies were performed in order to observe the effects of the most active compounds on substrate-enzyme relationship. Cytotoxicity studies and theoretical calculation of pharmacokinetic properties were also carried out to get an information about toxicity and pharmacokinetic profiles of the compounds. The compounds 26-29 were found to be nontoxic at their effective concentrations against AChE. A good pharmacokinetic profile was predicted for these compounds. Docking studies were performed for the most active compounds 26-29 and interaction modes with enzyme active sites were determined. Docking studies revealed that there is a strong interaction between the active sites of AChE enzyme and analyzed compounds.