摘要 |
A pharmaceutical composition comprising a compound of formula (I), or a pharmaceutically-acceptable salt or ester thereof in which X, R<1>, R<2>, R<3>, R<4>, R<5> and R<6> have the meanings given in the specification, is useful in the treatment of diseases of the central nervous system. The invention further relates to a compound of formula (I) or a pharmaceutically-acceptable salt or ester thereof useful in the treatment of diseases of the central nervous system. |