ETHYNYL DERIVATIVES AS POSITIVE ALLOSTERIC MODULATORS OF THE MGLUR5

摘要

The present invention relates to ethynyl derivatives of formula I wherein X is N or C-R, wherein R is hydrogen or halogen; G is N or CH; with the proviso that maximum one of G or X can be nitrogen; R1 is phenyl or pyridinyl, which are optionally substituted by halogen; R2 is hydrogen, lower alkyl, hydroxy, lower alkoxy or C(O)O-benzyl; R3,R3', R4, R4, R6, R6' are independently from each other hydrogen or lower alkyl; or R6 and R4 may form together with the carbon atom to which they are attached a C4-6-cycloalkyl ring, if m is 0 and n is 1 or 2; R5 is hydrogen or lower alkyl; n is 0, 1 or 2; m is 0 or 1; with the proviso that n and m are not simultaneously 0; 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). They may be used for the treatment of schizophrenia or cognitive disorders.