Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by abnormal aggregation of the tau protein. In this study, we designed a novel small molecule, Dalfina, through rational drug design and in silico docking simulations. Dalfina was optimized to selectively bind hyperphosphorylated tau isoforms and demonstrated favorable physicochemical properties for blood-brain barrier (BBB) permeability. Molecular docking was performed using Autodock Vina and revealed binding affinities ranging from-5.1 to-6.2 kcal/mol at key allosteric pockets (C1-C5) of tau. ADME profiling via SwissADME confirmed the compound's drug-likeness, CNS activity potential, and low toxicity risk. These findings support Dalfina as a promising lead compound for further experimental validation in tau-targeted Alzheimer's therapy.