The present invention is directed to therapeutic agents of the formula (I) which are atypical antipsychotics and which are useful in the treatment of neurological and psychiatric disorders associated with dopamine D2 and serotonin 5-HT2A neurotransmission dysfunction. wherein； R1 is C1-6alkyl, which is unsubstituted or substituted with 1-6 fluoro, wherein R1 and the hydroxyl group on the ring are attached to the same carbon atom； or a pharmaceutically acceptable salt thereof.
