The macrocyclic peptidic BACE-1 inhibitors 2a-c show moderate enzymatic and cellular activity. By exchange of the hydroxyethylene- to ethanolamine-transition state mimetic the peptidic character was reduced, providing the highly potent and selective inhibitor 3. Variation of the P' moiety resulted in the macrocyclic inhibitor 14. Both macrocycles show inhibition of BACE-1 in the brain of APP51/16 transgenic mice, 3 (NB-544) after intravenous and 14 (NB-533) after oral application.