Integrating Computational and Experimental Approaches to Identify Novel Pyrazolo[3,4-d]pyrimidine-containing Thiadiazole Frameworks for Treating Alzheimer’s Disease

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder associated with cholinergic dysfunction. We report a novel series of pyrazolo[3,4-[Formula: see text]] pyrimidine–thiadiazole derivatives as dual inhibitors of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). The compounds were characterized by 1 H NMR, [Formula: see text]C NMR, and HRMS, and their inhibitory activity was evaluated in vitro. Among the synthesized series, compound 10f emerged as the potent analogue, exhibiting [Formula: see text] values of 14.60 ± 1.80 nM (AChE) and 290.76 ± 2.90 nM (BuChE), with inhibitory potency comparable to the reference drug Donepezil. Molecular docking revealed that these compounds engage in both catalytic and peripheral anionic sites via [Formula: see text]–[Formula: see text] stacking and hydrogen-bond interactions, supporting a dual-binding mechanism. Density functional theory (DFT) calculations at the B3LYP/6-31G(d,p) level highlighted electronic features correlating with activity, while in silico ADMET profiling suggested favorable oral bioavailability and low toxicity. These results position this series as promising multifunctional lead candidates for further development in AD therapy.