The present invention relates to compounds of Formula (I) or a stereoisomer, tautomer, or pharmaceutically acceptable salt or solvate thereof, wherein X, Y, Z, Q, W, m, u, ring (A), R2, R3, R4, R5 and R6, are as defined in the specification and claims. The present invention provides a pharmaceutical composition containing the compounds of Formula (I) and a therapeutic method of treating and/or preventing Downs syndrome, β-amyloid angiopathy, disorders associated with cognitive impairment, Alzheimers disease, memory loss, attention deficit symptoms associated with Alzheimers disease, neurodegenerative diseases, pre-senile dementia, senile dementia and dementia associated with Parkinsons disease, Alzheimers disease and/or Down syndrome, age-related macular degeneration (AMD), glaucoma, olfactory function impairment, traumatic brain injury, progressive muscle diseases, Type II diabetes mellitus and cardiovascular diseases (stroke).
