The present invention is directed to compounds of Formula I: wherein X is CR1 or N; Y is CR2 or N; Z is NH or O; R1 is alkoxy, triazolyl, oxazolyl, isoxazolyl, oxadiazolyl, or pyrimidinyl; R2 is H, alkyl, or halo; R3 is H, alkyl, alkoxy, halo, triazolyl, oxazolyl, or pyrimidinyl; R4 is alkyl; R5 is pyridyl; benzoxazolyl; pyrimidinyl; pyridazinyl; quinoxalinyl; pyrazinyl; or quinazolinyl; wherein the pyridyl; benzoxazolyl; pyrimidinyl; pyridazinyl; quinoxalinyl; pyrazinyl; or quinazolinyl is optionally substituted with one or two substituents independently selected from the group consisting of alkyl, halo, or phenyl; and R6 is H or alkyl. Methods of making the compounds of Formula I are also described. The invention also relates to pharmaceutical compositions comprising compounds of Formula I. Methods using the compounds of the invention are also within the scope of the invention.