The invention relates to compounds of the formula R1 is selected from the group consisting of hydrogen, linear C1-C3 alkyl and fluorinated linear C1-C3 alkyl; R2 is hydrogen or methyl; R3 is selected from the group consisting of hydrogen, halogen, C1-C2-alkyl, fluorinated C1-C2-alkyl, C1-C2-alkoxy and fluorinated C1-C2-alkoxy, R4 is C1-C2-alkyl or fluorinated C1-C2-alkyl; n is 0, 1 or 2, and the physiologically tolerated salts of these compounds and the N-oxides thereof. The invention also relates to a pharmaceutical composition that comprises at least one compound of the formula I and/or at least one physiologically tolerated acid addition salt thereof, and further to a method for treating disorders that respond beneficially to dopamine D3 receptor antagonists or dopamine D3 agonists, said method comprising administering an effective amount of at least one compound or physiologically tolerated acid addition salt of the formula I to a subject in need thereof.