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, tert-butyl or cyclopropyl； R3 is Cl, F, CF3, cyano, methyl, methoxy or cyclopropyl； R4 is hydrogen, methyl or F； X is N or CH； Y is N or CH； with the proviso that X and Y are not simultaneously CH； 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.The compounds of formula I may be used in the treatment of psychiatric disorders such as 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CH3；R1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、第三丁基或環丙基；R3為Cl、F、CF3、氰基、甲基、甲氧基或環丙基；R4為氫、甲基或F；X為N或CH；Y為N或CH；限制條件為X及Y不同時為CH；或其醫藥上可接受的鹽或酸加成鹽、外消旋混合物或其相應對映異構體及/或光學異構體及/或立體異構體。該等式I化合物可用於治療精神病症，諸如精神分裂症、躁鬱症、強迫症或自閉症譜系障礙。
