| abstract |
The present invention relates to ethynyl derivatives of formula (I) wherein • R is phenyl, 3-fluorophenyl, 4-fluorophenyl or 2,5-di-fluorophenyl; • or to a pharmaceutically acceptable acid addition salt, in enantiomerically pure form with the absolute configuration as shown in formula (I). It has now surprisingly been found that the compounds of general formula I are allosteric modulators of the metabotropic glutamate receptor subtype 5 (mGluR5) whic are useful for he treatment of schizophrenia, cognitive disorders, fragile X sydrome or autism and which show advantageous biochemical-, physicochemical- and pharmacodynamic- properties compared to compounds of prior art. |