Lead optimization studies towards the discovery of novel carbamates as potent AChE inhibitors for the potential treatment of Alzheimer's disease

The optimization of our previous lead compound 1 (AChE IC50 = 3.31 μM) through synthesis and pharmacology of a series of novel carbamates is reported. The synthesized compounds were evaluated against mouse brain AChE enzyme using the colorimetric method described by Ellman et al. The three compounds 6a (IC50 = 2.57 μM), 6b (IC50 = 0.70 μM) and 6i (IC50 = 2.56 μM) exhibited potent in vitro AChE inhibitory activities comparable to the drug rivastigmine (IC50 = 1.11 μM). Among them, the compound 6b has been selected as possible optimized lead for further neuropharmacological studies. In addition, the AChE-carbamate Michaelis complexes of these potent compounds including rivastigmine and ganstigmine have been modeled using covalent docking protocol of GOLD and important direct/indirect interactions contributing to stabilization of the AChE-carbamate Michaelis complexes have been investigated.