Spiro-tricyclic ring compounds as beta-secretase modulators and methods of use

A compound of Formula I:

• or a stereoisomer, tautomer or pharmaceutically acceptable salt thereof, wherein
• A1 is CR6;
• A2 is CR5;
• A3 is CR4 or N;
• A4 is CR3 or N;
• A5 is CR1 or N;
• A6 is CR8;
• T1 is CR2;
• T2 is CR7, provided that (1) no more than two of A3, A4 and A5, is N, such that the fused ring comprising A3, A4, A5 and T1 form a fused benzene, pyridine or pyridazine ring;
• each of R1, R4, R5 and R8, independently, is H, F, Cl, Br, CF3, OCF3, C1-6-alkyl, CN, OH, —OC1-6-alkyl, —S(O)oC1-6-alkyl, —NHC1-6-alkyl or —C(O)C1-6-alkyl, wherein the C1-6-alkyl and C1-6-alkyl portion of —OC1-6-alkyl, —S(O)oC1-6-alkyl, —NHC1-6-alkyl and —C(O)C1-6-alkyl are optionally substituted with 1-3 substituents of F, oxo or OH;
• each of R2 and R7, independently, is H, halo, haloalkyl, haloalkoxyl, C1-6-alkyl, C2-6alkenyl, C2-6-alkynyl, C3-8-cycloalkyl, C4-8-cycloalkenyl, CN, OR10, SR10, NR10R10, C(O)R10, S(O)R10, S(O)2R10, NR10C(O)R10, C(O)NR10R10, NR10S(O)2R10, S(O)2NR10, NR10C(O)NR10R10, or a fully saturated or partially or fully unsaturated 4-, 5-, 6- or 7-membered monocyclic or 9- or 10-membered bicyclic ring formed of carbon atoms, said ring optionally including 1-4 heteroatoms selected from O, N, or S, wherein the C1-6-alkyl, C2-6-alkenyl, C2-6-alkynyl, C3-8-cycloalkyl, C4-8-cycloalkenyl and ring are optionally substituted, independently, with 1-5 substituents of R9 or R10;
• each of R3 and R6, independently, is H, halo, haloalkyl, haloalkoxyl, C1-6-alkyl, CN, OH, OC1-6-alkyl, S(O)oC1-6-alkyl, NHC1-6-alkyl or C(O)C1-6-alkyl;
• each R9, independently, is —C(O)R10, —S(O)2R10, —C(O)NHR10, —NHC(O)R10, —NHC(O)NHR10, —S(O)2NHR10 or —NHS(O)2R10;
• each R10, independently, is H, halo, haloalkyl, CN, OH, NO2, NH2, acetyl, oxo, C1-10-alkyl, C2-10-alkenyl, C2-10-alkenyl, C3-10-cycloalkyl, C4-10-cycloalkenyl, C1-10-alkylamino-, C1-10-dialkylamino-, C1-10-alkoxyl, C1-10-thioalkoxyl or a fully saturated or partially or fully unsaturated 3-8 membered monocyclic or a 6-12 membered bicyclic, said ring system formed of carbon atoms optionally including 1-3 heteroatoms if monocyclic or 1-6 heteroatoms if bicyclic, said heteroatoms selected from O, N, or S, wherein each of the C1-10-alkyl, C2-10-alkenyl, C2-10-alkynyl, C3-10-cycloalkyl, C4-10-cycloalkenyl, C1-10-alkylamino-, C1-10-dialkylamino-, C1-10-alkoxyl, C1-10-thioalkoxyl and ring of said ring system is optionally substituted independently with 1-5 substituents of halo, haloalkyl, haloalkoxyl, CN, NO2, NH2, OH, oxo, methyl, methoxyl, ethyl, ethoxyl, propyl, propoxyl, isopropyl, isopropoxyl, cyclopropyl, cyclopropylmethoxyl, butyl, butoxyl, isobutoxyl, tert-butoxyl, isobutyl, sec-butyl, tert-butyl, cyclobutyl, pentyl, cyclopentyl, hexyl, cyclohexyl, C1-10-alkylamino-, C1-10-dialkylamino-, C1-10-thioalkoxyl, benzyl or phenyl;
• W is CR1R1;
• X is O;
• Y is O;
• and
• Z is absent.