Disclosed are 3,4-dihydro-pyrrolo[1,2-a]pyrazin-1-ylamine derivatives of formula I where the substituents are as defined herein. These compounds are inhibitors of beta-secretase, also known as beta-site amyloid cleaving enzyme, BACE, BACE1, Asp2, or memapsin2. Also disclosed are pharmaceutical compositions comprising such compounds, to processes for preparing such compounds and compositions, and to the use of such compounds and compositions for the prevention and treatment of disorders in which beta-secretase is involved, such as Alzheimer&rsquos disease (AD), mild cognitive impairment, senility, dementia, dementia with Lewy bodies, Down&rsquos syndrome, dementia associated with stroke, dementia associated with Parkinson&rsquos disease or dementia associated with beta-amyloid.
