The present invention relates to ethynyl derivatives of formula I wherein R1 is hydrogen or F； n is 1 or 2 or to a pharmaceutically acceptable acid addition salt thereof. It has now surprisingly been found that the compounds of general formula I are metabotropic glutamate receptor antagonists (negative allosteric modulators) for use in the treatment of anxiety and pain, depression, Fragile-X syndrom, autism spectrum disorders, Parkinson’s disease, and gastroesophageal reflux disease (GERD).本發明係關於式I之乙炔基衍生物其中R1 係氫或F；n 為1或2或其醫藥上可接受之酸加成鹽。現已驚訝地發現，通式I之化合物係代謝型麩胺酸鹽受體拮抗劑(負向異位調節劑)，其用於治療焦慮症及疼痛、抑鬱症、脆性X染色體症候群、自閉症譜系障礙、帕金森氏病(Parkinson’s disease)及胃食道逆流疾病(GERD)。
