Fluorosulfate-containing pyrazole heterocycles as selective BuChE inhibitors: structure-activity relationship and biological evaluation for the treatment of Alzheimer's disease.

Novel scaffolds are expected to treat Alzheimer's disease, pyrazole-5-fluorosulfates were found as selective BuChE inhibitors. Compounds K1-K26 were assayed for ChE inhibitory activity, amongst them, compound K3 showed potent BuChE and hBuChE inhibition (IC50 = 0.79 μM and 6.59 μM). SAR analysis showed that 1-, 3-, 4-subtituent and 5-fluorosulfate of pyrazole ring affected BuChE inhibitory activity. Molecular docking showed that the fluorosulfate increased the binding affinity of hBuChE through π-sulphur interaction. Compound K3 was a reversible, mixed and non-competitive BuChE inhibitor (Ki = 0.77 μM) and showed remarkable neuroprotection, safe toxicological profile and BBB penetration. In vivo behavioural study showed that K3 treatment improved the Aβ1 - 42-induced cognitive impairment, and significantly prevented the effects of Aβ1 - 42 toxicity. Therefore, selective BuChE inhibitor K3 has potential to be further developed as AD therapeutics.