The present invention relates to the use of compounds of general formula (I) wherein R' is hydrogen or lower alkyl； R1 is halogen, lower alkyl, cycloalkyl or cyano； or is phenyl, optionally substituted by one to three substituents, selected from lower alkyl, lower alkyl substituted by halogen, lower alkoxy, lower alkoxy substituted by halogen, halogen, cyano, hydroxy, C(O)-NH-lower alkyl, CH2-C(O)-NH-lower alkyl, CH2-NH-C(O)-lower alkyl, CH2NH2, S(O)2CH3, S(O)2N(CH3)2, or by heterocycloalkyl groups； or is pyrazol-1, 4 or 5-yl, optionally substituted by lower alkyl； or is thiazol-5-yl, optionally substituted by one or two lower alkyl groups； or is pyridine 2, 3 or 4-yl, optionally substituted by lower alkyl, lower alkoxy, halogen or N(CH3)2； or is 3,6-dihydro-2H-pyran； or is benzo[d][1,3]dioxol-5-yl； or is 2,3-dihydrobenzo[b][1,4]dioxin-6-yl； R2 is hydrogen, lower alkyl or lower alkyl substituted by alkoxy； R3 is hydrogen, lower alkyl, lower alkyl substituted by halogen, lower alkyl substituted by hydroxy, NH-S(O)2-CH3, -(CH2)m-O-lower alkyl or -(CH2)n-S(O)2-CH3； or is -(CR2)n-phenyl, optionally substituted by -S(O)2CH3 or lower alkoxy； or is -(CH2)n-heterocycloalkyl, optionally substituted by lower alkyl and =O； or is -(CH2)n-heteroaryl, optionally substituted by one or two lower alkyl groups； or is -(CH2)n-cycloalkyl, optionally substituted by cyano； or R2 and R3 form together with the N atom to which they are attached a heterocyclic ring, selected from morpholine, piperidine, 1, 1-dioxo-thiomorpholine or piperazine which may be substituted by lower alkyl or C(O)O-lower alkyl, or may form a pyrrolidine ring, optionally substituted by hydroxy； R is independently from n hydrogen or lower alkyl； n is 0, 1, 2, 3； m is 2； or to a pharmaceutically acceptable acid addition salt, to a racemic mixture or to its corresponding enantiomer and/or optical isomers thereof, for the treatment of schizophrenia, obsessive-compulsive personality disorder, depression, bipolar disorders
