PYRAZOLIDIN-3-ONE DERIVATIVES

摘要

The present invention relates to ethynyl derivatives of formula I wherein X is N or CH; G is N or CH; with the proviso that maximum one of X or G can be nitrogen; R1 is phenyl or pyridyl, which are optionally substituted by halogen, lower alkyl or lower alkoxy; R2 is hydrogen, lower alkyl or may form together with R 4 a C3-C6-cycloalkyl; R3/R3'/R4/R4' are independently from each other hydrogen, lower alkyl or CF3; or to a pharmaceutically acceptable 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).