| abstract |
A pharmaceutical composition comprising a compound of formula (I), or a pharmaceutically-acceptable salt or ester thereof in which X, R?1, R2, R3, R4, R5 and R6¿ 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. |