Provided herein are sulfonamide derivatives or a stereoisomer, a geometric isomer, a tautomer, an N-oxide, a hydrate, a solvate, a metabolite, a pharmaceutically acceptable salt or a prodrug thereof, and their uses for treating Alzheimer's disease. Also provided herein are pharmaceutical compositions containing such compounds, and use of such compounds or pharmaceutical compositions thereof for managing or treating 5-HT6 receptor-mediated diseases, especially in the manufacture of a medicament for managing or treating Alzheimer's disease.
