The present invention relates to compounds of the general formula (I), and the pharmaceutically acceptable salts and solvates thereof, wherein Ar, Z and Y are as described herein and R1 is a group of the structure wherein n is 0 or 1; R2 is H, deuterium or methyl; R3 is methyl, trifluoromethyl, ethyl, or taken with R2 together forms a cyclopropyl group, or R3 forms a methylene bridge to the carbon atom marked *, which are suitable for the treatment of autoimmune diseases and chronic inflammation.