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 R1a, R1b, R1c, B, W, R3, R4 and R5 are defined herein. In another embodiment, the invention provides compounds of general Formula II wherein A1, A2, A3, A4, R1a, R1b, R1c, R2, R4, R5, W, X and Z 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 (AD), cognitive deficits and impairment, schizophrenia and other similar central nervous system conditions. The invention also comprises further embodiments of Formula II, intermediates and processes useful for the preparation of compounds of Formulas I and II.