A compound of the formula I wherein: A is a 5- or 6-membered aryl, heteroaryl or heterocyclyl group; B is a 5-7 membered heterocyclyl group containing one nitrogen, wherein one carbon of the heterocyclyl group is optionally substituted with an oxo group; R 1 and R 2 are independently selected from H, C 1-4 alkyl, C 3-6 cycloalkyl, tetrahydropyranyl, - CF 3, -CH 2 CF 3 and -CH 2 CH 2 CO 2 H; R 3 is selected from H and -CH 3; R 4 is selected from H, C 1-6 alkyl, C 3-7 cycloalkyl, -C C 1-6 alkyl, -CH 2 CF 3, -SO 2 C 1-6 alkyl, - SO 2 (CH 2) 1-3 CO 2 H, -CO 2 C 1-4 alkyl, heterocyclyl, aryl, heteroaryl, -(C 0-2 alkyl)heterocyclyl, - (C 1-2 alkyl)aryl and -(C 1-2 alkyl)heteroaryl, wherein said heterocyclyl is selected from tetrahydrofuranyl, azetidinyl, pyrrolidinyl, pyranyl, tetrahydropyranyl, dioxanyl, thiomorpholinyl, 1,1-dioxo-1λ 6 -thiomorpholinyl, morpholinyl, piperidinyl, piperazinyl, and azepinyl, and said heterocyclyl, cycloalkyl, aryl and heteroaryl are optionally substituted with one to two groups independently selected from C 1-3 alkyl, -CF 3, and halogen; R 5 is selected from H, -C 1-3 alkyl, -OCH 3, -CF 3, -CN and Cl; and R 6 is selected from H and CH 3; provided that R 5 and R 6 are not both H; wherein "aryl" as mentioned hereinbefore, either alone or in combination with another radical, denotes, unless defined otherwise, a carbocyclic aromatic monocyclic group containing 6 carbon atoms which may be further fused to a second 5- or 6-membered carbocyclic group which may be aromatic, saturated or unsaturated, and wherein "heteroaryl" as mentioned hereinbefore means, unless defined otherwise, an aromatic 5 to 6-membered monocyclic heteroaryl or an aromatic 7 to 11-membered heteroaryl bicyclic ring where at least one of the rings is aromatic, wherein the heteroaryl ring contains 1-4 heteroatoms, and wherein "heterocyclyl" as mentioned hereinbefore means, unless defined otherwise, a stable nonaromatic 4-8 membered monocyclic heterocyclic radical or a stable nonaromatic 6 to 11-membered fused bicyclic, bridged bicyclic or spirocyclic heterocyclic radical; or a salt thereof. A is a 5- or 6-membered aryl, heteroaryl or heterocyclyl group; B is a 5-7 membered heterocyclyl group containing one nitrogen, wherein one carbon of the heterocyclyl group is optionally substituted with an oxo group; R 1 and R 2 are independently selected from H, C 1-4 alkyl, C 3-6 cycloalkyl, tetrahydropyranyl, - CF 3, -CH 2 CF 3 and -CH 2 CH 2 CO 2 H; R 3 is selected from H and -CH 3; R 4 is selected from H, C 1-6 alkyl, C 3-7 cycloalkyl, -C C 1-6 alkyl, -CH 2 CF 3, -SO 2 C 1-6 alkyl, - SO 2 (CH 2) 1-3 CO 2 H, -CO 2 C 1-4 alkyl, heterocyclyl, aryl, heteroaryl, -(C 0-2 alkyl)heterocyclyl, - (C 1-2 alkyl)aryl and -(C 1-2 alkyl)heteroaryl, wherein said heterocyclyl is selected from tetrahydrofuranyl, azetidinyl, pyrrolidinyl, pyranyl, tetrahydropyranyl, dioxanyl, thiomorpholinyl, 1,1-dioxo-1λ 6 -thiomorpholinyl, morpholinyl, piperidinyl, piperazinyl, and azepinyl, and said heterocyclyl, cycloalkyl, aryl and heteroaryl are optionally substituted with one to two groups independently selected from C 1-3 alkyl, -CF 3, and halogen; R 5 is selected from H, -C 1-3 alkyl, -OCH 3, -CF 3, -CN and Cl; and R 6 is selected from H and CH 3; provided that R 5 and R 6 are not both H; wherein "aryl" as mentioned hereinbefore, either alone or in combination with another radical, denotes, unless defined otherwise, a carbocyclic aromatic monocyclic group containing 6 carbon atoms which may be further fused to a second 5- or 6-membered carbocyclic group which may be aromatic, saturated or unsaturated, and wherein "heteroaryl" as mentioned hereinbefore means, unless defined otherwise, an aromatic 5 to 6-membered monocyclic heteroaryl or an aromatic 7 to 11-membered heteroaryl bicyclic ring where at least one of the rings is aromatic, wherein the heteroaryl ring contains 1-4 heteroatoms, and wherein "heterocyclyl" as mentioned hereinbefore means, unless defined otherwise, a stable nonaromatic 4-8 membered monocyclic heterocyclic radical or a stable nonaromatic 6 to 11-membered fused bicyclic, bridged bicyclic or spirocyclic heterocyclic radical; or a salt thereof.