THE PRESENT INVENTION RELATES TO COMPOUNDS HAVING THE GENERAL FORMULA (I) WITH THE DEFINITIONS OF X, Y, R₁ R₂, R₃, R₄, R₉, R₁₀ GIVEN BELOW, AND SOLVATES, HYDRATES, ESTERS, AND PHARMACEUTICALLY ACCEPTABLE SALTS THEREOF. FURTHERMORE, THE INVENTION RELATES TO THE USE OF SAID COMPOUNDS FOR THE TREATMENT OF ALZHEIMERS DISEASE AND THEIR USE FOR THE MODULATION OF ����-SECRETASE ACTIVITY.