| abstract |
The present invention relates to ethynyl derivatives of the formula I (see Formula) in which: R1 is phenyl, which is optionally substituted by 1-2 halogen atoms, chosen from fluorine and chlorine; or a pharmaceutically acceptable acid addition salt, in enantiomerically pure form. It has been found that the compounds of the general formula I are allosteric modulators of the metabotropic glutamate receptor of subtype 5 (mGluR5). |