| abstract |
The present invention relates to ethynyl derivatives of formula (I) wherein X is N or C-R 1 ; Y is N or C-R 2 ; Z is CH or N; R 4 is a 6-membered aromatic substituent containing 0, 1 or 2 nitrogen atoms, optionally substituted by 1 to 3 groups, selected from halogen, lower alkyl, lower alkoxy or NRR'; R 1 is hydrogen, lower alkyl, lower alkoxy, hydroxy, lower hydroxyalkyl, lower cycloalkyl or is heterocycloalkyl optionally substituted with hydroxy or alkoxy; R 2 is hydrogen, CN, lower alkyl or heterocycloalkyl; R and R' are independently from each other hydrogen or lower alkyl; or to a pharmaceutically acceptable salt or acid addition salt, to a racemic mixture, or to its corresponding enantiomer and/or optical isomer and/or stereoisomer thereof. It has now surprisingly been found that the compounds of general formula (I) are positive allosteric modulators (PAM) of the metabotropic glutamate receptor subtype 5 (mGluR5) and they are therefore useful for the treatment of diseases related to this receptor. |