Investigation of potent inhibitors of cholinesterase based on thiourea and pyrazoline derivatives: Synthesis, inhibition assay and molecular modeling studies

Owing to the desperate need of new drugs development to treat Alzheimer's ailment the synthesis of 1-aroyl-3-(5-(4-chlorophenyl)-1,2,4-triazole-3-thioneaminylthioureas (2-6) starting from (4-amino-5-(4-chlorophenyl)-4H-1,2,4-triazole-3-thiol) (1) and synthesis of 1-(3-(4-aminophenyl)-5-phenyl-4,5-dihydro-1H-pyrazol-1-yl)-2-(4-isobutylphenyl)propan-1-one (7-9) starting from 2-(4-isobutylphenyl) propanehydrazide (a) with the cyclization with substituted chalcones (c-e) was carried out. To check the biological potential of the synthesized compounds, all were subjected to acetylcholinesterase (AChE) and butrylcholinesterase (BChE) inhibition assays. The most potent and selective inhibitor for the acetylcholinesterase was compound 7 having an inhibitory concentration of 123 +/- 51 nM, whereas, compound 6 was found as selective inhibitor of butyrylcholinesterase (BChE) with an IC50 value of 201 +/- 80 nM. However, the compounds 1 and 2 were found as dual inhibitors i.e. active against both acetylcholinesterase as well as butyrylcholinesterase.