A compound of Formula wherein: X is O or NR 3; wherein R 3 is: H, C alkyl, CH 2 CF 3, C alkylOH, C alkenyl, CH 2 OC alkenyl, CH 2 OC alkyl, C C alkyl, CONH 2, CONHC alkyl, SONH 2, CH 2 Ph, CH 2 heteroaryl, CH 2 heterocyclyl, CH 2 cycloalkyl, C cycloalkyl, or SO 2 C alkyl; wherein said heteroaryl, heterocyclyl, or cycloalkyl may be optionally substituted with up to three substituents selected from the group consisting of: F, OCH 3, CH 3, and OH; Y 1 and Y 2 are CH or N, provided that both Y 1 and Y 2 are not N; Z is O, CH 2, S, S, SO 2, or a direct bond; wherein R a and R b are independently selected from the group consisting of: H, OH, F, CH 3, CF 3, OCF 3, and OCH 3; R 1 is pyridyl, pyridyl- N -oxide, pyrimidyl, pyrazolyl, indolyl, thiazolyl, benzo[1,3]dioxol-5-yl, pyrazolyl, oxazolyl, isoxazolyl, imidazolyl, phenyl, thiazolyl, isothiazolyl, 3- H -thiazol-2-onyl, benzooxazolyl, furyl, [1,2,4]oxadiazolyl, [1,3,4]thiadiazolyl, C cycloalkyl, C alkyl, C alkylOH, CH 2 OC alkenyl, CH 2 OC alkyl, CH Z C NH 2, CO 2 C alkyl, -CN, C NH 2, C NHCH 2 CH 2 OH, OTBS, OH, OC alkyl, OC alkenyl, NH 2, NHBOC, or pyridonyl; wherein said pyridyl, pyridyl- N -oxide, pyrimidyl, pyrazolyl, indolyl, thiazolyl, benzo[1,3]dioxol-5-yl, pyrazolyl, oxazolyl, isoxazolyl, imidazolyl, phenyl, thiazolyl, isothiazolyl, 3-H-thiazol-2-onyl, benzooxazolyl, furyl, [1,2,4]oxadiazolyl, [1,3,4]thiadiazolyl, C cycloalkyl, C alkyl, or pyridonyl, may be optionally substituted with one or two substituents, independently selected from the group consisting of: CH 2 C NH 2, C alkoxy, OC cycloalkyl, OCH 2 CF 3, OCH 2 Ph, F, CN, Cl, OCF 3, CF 3, CH 2 CN, C alkyl, CH 2 CF 3, N(C alkyl) 2, C alkylOH, Si(CH 3) 3, -C≡CH SCH 3, S CH 3, SO 2 CH 3, pyrrolidinyl, OH, NH 2, NHCN, CO 2 H, CONH 2, NHCO 2 C alkyl, N(SO 2 CH 3) 2, NHSO 2 CH 3, NHC CF 3, NHC alkyl, NHCO 2 H, NHCO 2 C alkyl, NHCOC alkyl, NHCONH 2, NHCONHC alkyl, and Br; R 2 is F, NH 2, H, or OH; and tautomers, and pharmaceutically acceptable salts thereof. X is O or NR 3; wherein R 3 is: H, C alkyl, CH 2 CF 3, C alkylOH, C alkenyl, CH 2 OC alkenyl, CH 2 OC alkyl, C C alkyl, CONH 2, CONHC alkyl, SONH 2, CH 2 Ph, CH 2 heteroaryl, CH 2 heterocyclyl, CH 2 cycloalkyl, C cycloalkyl, or SO 2 C alkyl; wherein said heteroaryl, heterocyclyl, or cycloalkyl may be optionally substituted with up to three substituents selected from the group consisting of: F, OCH 3, CH 3, and OH; Y 1 and Y 2 are CH or N, provided that both Y 1 and Y 2 are not N; Z is O, CH 2, S, S, SO 2, or a direct bond; wherein R a and R b are independently selected from the group consisting of: H, OH, F, CH 3, CF 3, OCF 3, and OCH 3; R 1 is pyridyl, pyridyl- N -oxide, pyrimidyl, pyrazolyl, indolyl, thiazolyl, benzo[1,3]dioxol-5-yl, pyrazolyl, oxazolyl, isoxazolyl, imidazolyl, phenyl, thiazolyl, isothiazolyl, 3- H -thiazol-2-onyl, benzooxazolyl, furyl, [1,2,4]oxadiazolyl, [1,3,4]thiadiazolyl, C cycloalkyl, C alkyl, C alkylOH, CH 2 OC alkenyl, CH 2 OC alkyl, CH Z C NH 2, CO 2 C alkyl, -CN, C NH 2, C NHCH 2 CH 2 OH, OTBS, OH, OC alkyl, OC alkenyl, NH 2, NHBOC, or pyridonyl; wherein said pyridyl, pyridyl- N -oxide, pyrimidyl, pyrazolyl, indolyl, thiazolyl, benzo[1,3]dioxol-5-yl, pyrazolyl, oxazolyl, isoxazolyl, imidazolyl, phenyl, thiazolyl, isothiazolyl, 3-H-thiazol-2-onyl, benzooxazolyl, furyl, [1,2,4]oxadiazolyl, [1,3,4]thiadiazolyl, C cycloalkyl, C alkyl, or pyridonyl, may be optionally substituted with one or two substituents, independently selected from the group consisting of: CH 2 C NH 2, C alkoxy, OC cycloalkyl, OCH 2 CF 3, OCH 2 Ph, F, CN, Cl, OCF 3, CF 3, CH 2 CN, C alkyl, CH 2 CF 3, N(C alkyl) 2, C alkylOH, Si(CH 3) 3, -C≡CH SCH 3, S CH 3, SO 2 CH 3, pyrrolidinyl, OH, NH 2, NHCN, CO 2 H, CONH 2, NHCO 2 C alkyl, N(SO 2 CH 3) 2, NHSO 2 CH 3, NHC CF 3, NHC alkyl, NHCO 2 H, NHCO 2 C alkyl, NHCOC alkyl, NHCONH 2, NHCONHC alkyl, and Br; R 2 is F, NH 2, H, or OH; and tautomers, and pharmaceutically acceptable salts thereof.