A compound of the formula wherein A is phenyl or pyrazolyl, which is optionally substituted with one to three groups independently selected from the group consisting of halo, oxo, cyano, R 6, OR 6, C OR 6, NR 6 R 7, NHC OR 6, NHC O-C 1-3 alkyl-OR 7 and NHC O-C 1-3 alkyl-C OH; B is phenyl, pyrrolyl, imidazolyl, triazolyl, pyridinyl, pyridinyl-N-oxide, pyridazinyl, pyrimidinyl, pyrazinyl and triazinyl wherein said groups are optionally substituted with one to three groups independently selected from the group consisting of halo, oxido, cyclopropyl and R 6; R 1 is aryl, which optionally is substituted with one to four substituents independently selected from the group consisting of chloro, fluoro, iodo, methyl, cyclopropyl, OCF 3, OCF 2, CF 3, CF 2, and heteroaryl (which is optionally substituted with halo, cyano, cyclopropyl, C OH, methyl, CF 3 or CF 2), wherein 'aryl' represents a stable monocyclic or bicyclic carbon ring of up to 12 atoms in each ring, wherein at least one ring is aromatic and wherein 'heteroaryl' represents a stable monocyclic or bicyclic ring system of up to 10 atoms in each ring, wherein at least one ring is aromatic and at least one ring contains from 1 to 4 heteroatoms selected from O, N and S; R 2 is hydrogen, cyano, halo, R 6 or OR 6; R 3 is hydrogen, cyano, halo, R 6 or OR 6; R 4 is C 1-6 alkyl, CO 2 R 6, COR 6 or CONR 7 R 8, wherein said alkyl is optionally substituted with one to three halo; each R 6 is independently hydrogen or C 1-6 alkyl, which is optionally substituted with one to three groups independently selected from the group consisting of halo and hydroxy; each R 7 is independently hydrogen or C 1-6 alkyl, which is optionally substituted with one to three groups independently selected from the group consisting of halo and hydroxy; R 8 is hydrogen or C 1-6 alkyl; R a is hydrogen, hydroxy or O(C 1-6 alkyl); or a pharmaceutically acceptable salt thereof. B is phenyl, pyrrolyl, imidazolyl, triazolyl, pyridinyl, pyridinyl-N-oxide, pyridazinyl, pyrimidinyl, pyrazinyl and triazinyl wherein said groups are optionally substituted with one to three groups independently selected from the group consisting of halo, oxido, cyclopropyl and R 6; R 1 is aryl, which optionally is substituted with one to four substituents independently selected from the group consisting of chloro, fluoro, iodo, methyl, cyclopropyl, OCF 3, OCF 2, CF 3, CF 2, and heteroaryl (which is optionally substituted with halo, cyano, cyclopropyl, C OH, methyl, CF 3 or CF 2), wherein 'aryl' represents a stable monocyclic or bicyclic carbon ring of up to 12 atoms in each ring, wherein at least one ring is aromatic and wherein 'heteroaryl' represents a stable monocyclic or bicyclic ring system of up to 10 atoms in each ring, wherein at least one ring is aromatic and at least one ring contains from 1 to 4 heteroatoms selected from O, N and S; R 2 is hydrogen, cyano, halo, R 6 or OR 6; R 3 is hydrogen, cyano, halo, R 6 or OR 6; R 4 is C 1-6 alkyl, CO 2 R 6, COR 6 or CONR 7 R 8, wherein said alkyl is optionally substituted with one to three halo; each R 6 is independently hydrogen or C 1-6 alkyl, which is optionally substituted with one to three groups independently selected from the group consisting of halo and hydroxy; each R 7 is independently hydrogen or C 1-6 alkyl, which is optionally substituted with one to three groups independently selected from the group consisting of halo and hydroxy; R 8 is hydrogen or C 1-6 alkyl; R a is hydrogen, hydroxy or O(C 1-6 alkyl); or a pharmaceutically acceptable salt thereof.