The present invention relates to compounds of formula I wherein R1’ is CH3 R1 is methyl, ethyl, CF3, CH2OH, cyclopropyl or cyano, or R1’ and R1 may form together a 1,1-dioxo-tetrahydro-thiophen-3-yl ring； R2 is hydrogen, methyl, ethyl, isopropyl, tertbutyl, cyclopropyl or CF3； R3 is Cl, F, CF3, methyl, methoxy, isopropyl or cyclopropyl； R4 is hydrogen, methyl, F or Cl； or to a pharmaceutically acceptable salt or acid addition salt, to a racemic mixture, or to its corresponding enantiomer and/or optical isomer and/or stereoisomer thereof for use in the treatment of schizophrenia, bipolar disorder, obsessive-compulsive disorder or autism spectrum disorder.本發明係關於式I化合物其中R1'為CH3R1為甲基、乙基、CF3、CH2OH、環丙基或氰基，或R1'及R1可一起形成1,1-二側氧基-四氫-噻吩-3-基環；R2為氫、甲基、乙基、異丙基、第三丁基、環丙基或CF3；R3為Cl、F、CF3、甲基、甲氧基、異丙基或環丙基；R4為氫、甲基、F或Cl；或關於其醫藥學上可接受之鹽或酸加成鹽，關於外消旋混合物，或關於其相應對映異構體及/或光學異構體及/或其立體異構體，其用於治療精神分裂症、躁鬱症、強迫症或自閉譜系疾患。
