Abstract: Disclosed are compounds of the formula or a pharmaceutically acceptable salt or solvate thereof, wherein R1 is R is —C(O)—N(R27)(R28) or and the remaining variables are as defined in the specification. Also disclosed are pharmaceutical compositions comprising the compounds of formula I. Also disclosed are methods of treating cognitive or neurodegenerative diseases such as Alzheimer's disease. Also disclosed are pharmaceutical compositions and methods of treating cognitive or neurodegenerative diseases comprising the compounds of formula I in combination with a ?-secretase inhibitor other than those of formula I, an HMG-CoA reductase inhibitor, a gamma-secretase inhibitor, a non-steroidal anti-inflammatory agent, an N-methyl-D-aspartate receptor antagonist, a cholinesterase inhibitor or an anti-amyloid antibody.

Abstract: Disclosed are novel compounds of the formula or a pharmaceutically acceptable salt or solvate thereof, wherein R1 is X is —O—, —C(R14)2— or —N(R)—; Z is —C(R14)2— or —N(R)—; t is 0, 1, 2 or 3; each R and R2 is independently H, alkyl, cycloalkyl, cycloalkylalkyl, aryl, heteroaryl, heterocycloalkyl, arylalkyl, heteroarylalkyl, heterocycloalkylalkyl, alkenyl or alkynyl; each R14 is H, alkyl, alkenyl, alkynyl, halo, —CN, haloalkyl, cycloalkyl, cycloalkylalkyl, aryl, heteroaryl, heterocycloalkyl, arylalkyl, heteroarylalkyl, heterocycloalkylalkyl, —OR35, —N(R24)(R25) or —SR35; R41 is alkyl, cycloalkyl, —SO2(alkyl), —C(O)-alkyl, —C(O)-cycloalkyl or -alkyl-NH—C(O)CH3; and the remaining variables are as defined in the specification. Also disclosed are pharmaceutical compositions comprising the compounds of formula I and methods of treating cognitive or neurodegenerative diseases with compounds of formula I.