| abstract |
Pharmaceutical compounds of the the formula <CHEM> in which R<1> is hydrogen or C1-6 alkyl, R<2> is hydrogen, C1-6 alkyl optionally substituted by C3-9 cycloalkyl or optionally substituted phenyl, C3-9 cycloalkyl, optionally substituted phenyl, or -SR<4> where R<4> is C1-6 alkyl optionally substituted by C3-9 cycloalkyl or optionally substituted phenyl, or C3-9 cycloalkyl, R<3> is hydrogen, C1-6 alkyl optionally substituted by C3-9 cycloalkyl or optionally substituted phenyl, C3-9 cycloalkyl, or optionally substituted phenyl, and either X and Y are both hydrogen or together are =O; and acid addition salts thereof. These compounds show useful effects on the central nervous system. |