4-Piperazinyl-Pyrimidine Compounds Suitable for Treating Disorders that Respond to Modulation of the Dopamine D3 Receptor

4-piperazinylpyrimidine compounds of the formula I

• wherein
• Ar is phenyl or an aromatic 5- or 6-membered C-bound heteroaromatic radical, comprising 1 nitrogen atom as ring member and 0, 1, 2 or 3 further heteroatoms, independently of each other, selected from O, S and N, as ring members, wherein Ar may carry 1, 2 or 3 radicals Ra which are, independently of each other, selected from the group consisting of C1-C6 alkyl, C3-C6 cycloalkyl, C1-C4 alkoxy-C1-C4-alkyl, C1-C4 haloalkyl, CN, NO2, halogen, OR2, NR3R4, C(O)NR3R4, O—C(O)NR3R4, SO2NR3R4, COOR5, SR6, SOR6, SO2R6, O—C(O)R7, COR7 or C3-C5 cycloalkylmethyl, wherein Ar may also carry a phenyl group or an aromatic 5- or 6-membered C-bound heteroaromatic radical, comprising 1 nitrogen atom as ring member and 0, 1, 2 or 3 further heteroatoms, independently of each other, selected from O, S and N, wherein the last two mentioned radicals may carry 1, 2, 3 or 4 of the aforementioned radicals Ra;
• X is a single bond, CONR8, S, or O;
• A is linear C3-C4 alkylene, which may comprise a double bond or a triple bond and which also may carry 1 or 2 methyl groups;
• R1, R1a are independently from each other selected from C3-C6 alkyl, C1-C2-fluoroalkyl, or C3-C6 cycloalkyl, which may carry 1 or 2 C1-C4 alkyl groups, provided that at least one of the radicals R1, R1a is selected from C3-C4 cycloalkyl optionally substituted with a C1-C4 alkyl group;
• R2, R3, R4, R5, R6, and R7 independent of each other are H, C1-C6 alkyl, optionally substituted with OH, C1-C4 alkoxy or phenyl, C1-C4 haloalkyl or phenyl, which may carry 1, 2 or 3 radicals selected from the group consisting of C1-C6 alkyl, C1-C6 alkoxy, NR3R4, CN, C1-C2 fluoroalkyl oder halogen, R4 may also be a radical COR9, wherein R9 is hydrogen, C1-C6 alkyl, C1-C6 alkoxy or phenyl, which may carry 1, 2 or 3 radicals selected from the group consisting of C1-C6 alkyl, C1-C6 alkoxy, NR3R4, CN, C1-C2 fluoroalkyl oder halogen, R3 and R4 may together with the nitrogen atom to which they are bound form a N-bound 5 or 6 membered saturated heterocyle, which may comprise an oxygen atom or an additional nitrogen atom as a ring member and which may carry 1, 2, 3 or 4 C1-C6 alkyl groups;
• and
• R8 is hydrogen or C1-C6 alkyl;
• their tautomers, enantiomers and diastereomers, and the physiologically tolerated acid addition salts of these compounds and the enantiomers, diastereomers and tautomers thereof.