Compounds of the general formula ##STR1## wherein R.sub.1 is n-propyl or cyclobutyl; R.sub.2 is isopropyl, tertiary butyl, cyclobutyl, cyclopentyl or cyclohexyl; R.sub.3 is hydrogen; R.sub.4 is hydrogen or methyl; as (R)-enantiomer in the form of free base or pharmaceutically acceptable salts thereof, process for their preparation, pharmaceutical composition, use of and method of treatment of disorders in CNS.
通式为##STR1##的化合物,其中R.sub.1是正丙基或
环丁基;R.sub.2是异丙基、叔丁基、
环丁基、环戊基或环己基;R.sub.3是氢;R.sub.4是氢或甲基;以(R)-对映体的自由碱形式或其药学上可接受的盐形式,它们的制备方法,药物组成物,用途和治疗中枢神经系统疾病的方法。