Abstact

Phosphodiesterase 2 (PDE2), a dual-substrate cyclic nucleotide hydrolase, represents a potential therapeutic target for cognitive impairment. This study aims to develop 2,4,5,6-tetrahydro-7H-pyrazolo[3,4-c]pyridine-7-one-based PDE2 inhibitors with favorable drug-like properties for the treatment of Alzheimer's disease. Through scaffold hopping and cocrystal structure analysis, compound 14c was identified as an effective PDE2 inhibitor (IC50 = 0.6 μM, aqueous solubility = 60.36 μg/mL). Moreover, 14c demonstrated favorable hepatic microsomal stability, pharmacokinetic properties (t1/2 = 4.4 h, F% = 95.66 %) and promising safety both in vitro and in vivo. In the OKA-induced AD mice models, administration of 14c significantly improved memory deficits and cognitive impairment. Molecular mechanism studies revealed that the neuroprotective effects of 14c were mediated through the PKA/CREB/BDNF signaling pathway. Collectively, these findings represent significant advances in developing PDE2 inhibitors with favorable drug-like properties and establish a solid foundation for their therapeutic application in AD.