The present invention relates to a compound of formula (I), an optical isomer or a pharmaceutically acceptable salt thereof, its preparation and uses, wherein R is defined as herein. Such compounds can be presented as an optical isomer or a racemic mixture. The compounds can be metabolized in vivo to form a pharmacologically active substance as antagonist of neurotransmitters, and can be used for the treatment of the related mental disorders such as schizophrenia.
