A compound of formula wherein Ar is selected from the group consisting of: wherein X is CH or N; R 5 is H, halogen or CN; and R 4 is selected from the group consisting of C 1-6 -alkyl, C 3-7 -CyCloalkyl, heterocyclyl, -(CH 2) 1-3 -C(=O)-NH-(C 1-5 -alkyl) and -(CH 2) 1-3 -C(=O)-N(CH 3)-(C 1-5 -alkyl); wherein each alkyl or cycloalkyl group of R 4 is optionally substituted with one or more F or one CN, OH or CF 3; wherein each heterocyclyl is optionally substituted with one or more F and/or one OH or -O-(C 1-3 -alkyl); or R 4 is selected from the group consisting of R 1 is halogen, C 1-3 -alkyl or -O-(C 1-3 -alkyl); R 2 is selected from the group consisting of OH, -O-(C 1-6 -alkyl), -O-(CH 2) 1-3 -(C 3-7 -cycloalkyl), -O-(CH 2) 1-3 -O-(C 1-3 -alkyl), -O-heterocyclyl and -O-(CH 2) 2-4 -heterocyclyl, wherein in the definition of R 2, each heterocyclyl is optionally substituted with one C 1-3 -alkyl group, and wherein one CH 2 group of said heterocyclyl of R 2 may be replaced with a carbonyl group; R 3 is selected from the group consisting of: wherein R 6 is C 1-2 -alkyl; R 7 is C 1-5 -alkyl, C 3-7 -CyCloalkyl or heterocyclyl, wherein the alkyl group of R 7 is optionally substituted with one or more F or with one OH or -O-(C 1-3 -alkyl), and wherein the heterocyclyl group of R 7 is tetrahydropyranyl; and or wherein R 6 and R 7 together with the sulfur atom to which they are attached form a 4- to 7-membered saturated or partly unsaturated heterocycle that may be substituted in any position not adjacent to the sulfur atom by one or two F, OH or -O-(C 1-3 -alkyl) or by one or two C 1-3 -alkyl and that further to the sulfur atom may contain one additional heteroatom selected from the group consisting of O, S and NR N, wherein R N is H or C 1-3 -alkyl, wherein, if not otherwise specified, each alkyl group in the above definitions is linear or branched and may be substituted with one to three F; or a salt thereof. Ar is selected from the group consisting of: wherein X is CH or N; R 5 is H, halogen or CN; and R 4 is selected from the group consisting of C 1-6 -alkyl, C 3-7 -CyCloalkyl, heterocyclyl, -(CH 2) 1-3 -C(=O)-NH-(C 1-5 -alkyl) and -(CH 2) 1-3 -C(=O)-N(CH 3)-(C 1-5 -alkyl); wherein each alkyl or cycloalkyl group of R 4 is optionally substituted with one or more F or one CN, OH or CF 3; wherein each heterocyclyl is optionally substituted with one or more F and/or one OH or -O-(C 1-3 -alkyl); or R 4 is selected from the group consisting of wherein X is CH or N; R 5 is H, halogen or CN; and R 4 is selected from the group consisting of C 1-6 -alkyl, C 3-7 -CyCloalkyl, heterocyclyl, -(CH 2) 1-3 -C(=O)-NH-(C 1-5 -alkyl) and -(CH 2) 1-3 -C(=O)-N(CH 3)-(C 1-5 -alkyl); wherein each alkyl or cycloalkyl group of R 4 is optionally substituted with one or more F or one CN, OH or CF 3; wherein each heterocyclyl is optionally substituted with one or more F and/or one OH or -O-(C 1-3 -alkyl); or wherein each alkyl or cycloalkyl group of R 4 is optionally substituted with one or more F or one CN, OH or CF 3; wherein each heterocyclyl is optionally substituted with one or more F and/or one OH or -O-(C 1-3 -alkyl); or R 4 is selected from the group consisting of R 1 is halogen, C 1-3 -alkyl or -O-(C 1-3 -alkyl); R 2 is selected from the group consisting of OH, -O-(C 1-6 -alkyl), -O-(CH 2) 1-3 -(C 3-7 -cycloalkyl), -O-(CH 2) 1-3 -O-(C 1-3 -alkyl), -O-heterocyclyl and -O-(CH 2) 2-4 -heterocyclyl, wherein in the definition of R 2, each heterocyclyl is optionally substituted with one C 1-3 -alkyl group, and wherein one CH 2 group of said heterocyclyl of R 2 may be replaced with a carbonyl group; R 3 is selected from the group consisting of: wherein R 6 is C 1-2 -alkyl; R 7 is C 1-5 -alkyl, C 3-7 -CyCloalkyl or heterocyclyl, wherein the alkyl group of R 7 is optionally substituted with one or more F or with one OH or -O-(C 1-3 -alkyl), and wherein the heterocyclyl group of R 7 is tetrahydropyranyl; and or wherein R 6 and R 7 together with the sulfur atom to which they are attached form a 4- to 7-membered saturated or partly unsaturated heterocycle that may be substituted in any position not adjacent to the sulfur atom by one or two F, OH or -O-(C 1-3 -alkyl) or by one or two C 1-3 -alkyl and that further to the sulfur atom may contain one additional heteroatom selected from the group consisting of O, S and NR N, wherein R N is H or C 1-3 -alkyl, wherein R 6 is C 1-2 -alkyl; R 7 is C 1-5 -alkyl, C 3-7 -CyCloalkyl or heterocyclyl, wherein the alkyl group of R 7 is optionally substituted with one or more F or with one OH or -O-(C 1-3 -alkyl), and wherein the heterocyclyl group of R 7 is tetrahydropyranyl; and wherein the alkyl group of R 7 is optionally substituted with one or more F or with one OH or -O-(C 1-3 -alkyl), and wherein the heterocyclyl group of R 7 is tetrahydropyranyl; and or wherein R 6 and R 7 together with the sulfur atom to which they are attached form a 4- to 7-membered saturated or partly unsaturated heterocycle that may be substituted in any position not adjacent to the sulfur atom by one or two F, OH or -O-(C 1-3 -alkyl) or by one or two C 1-3 -alkyl and that further to the sulfur atom may contain one additional heteroatom selected from the group consisting of O, S and NR N, wherein R N is H or C 1-3 -alkyl, wherein, if not otherwise specified, each alkyl group in the above definitions is linear or branched and may be substituted with one to three F; or a salt thereof.