Abstract: The present invention comprises a new class of compounds useful for the modulation of Beta-secretase enzyme activity and for the treatment of Beta-secretase mediated diseases, including Alzheimer's disease (AD) and related conditions. In one embodiment, the compounds have a general Formula I wherein A1, A2, A3, A4, A5, A6, R2, R7, X, Y and Z of Formula I are defined herein. The invention also includes use of these compounds in pharmaceutical compositions for treatment, prophylactic or therapeutic, of disorders and conditions related to the activity of beta-secretase protein. Such disorders include, for example, Alzheimer's Disease, cognitive deficits, cognitive impairment, schizophrenia and other central nervous system conditions related to and/or caused by the formation and/or deposition of plaque on the brain. The invention also comprises further embodiments of Formula I, intermediates and processes useful for the preparation of compounds of Formula I.