The present invention relates to ethynyl derivatives of formula Iwherein Y is N or CH R1is fluoro or chloro 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 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乙炔基衍生物或其醫藥上可接受的酸加成鹽、外消旋混合物或其相應對映異構體及/或光學異構體及/或立體異構體，其中Y為N或CH，R1為氟或氯。現已出乎意料地發現，通式I化合物為用於治療焦慮及疼痛、抑鬱、X染色體易碎症候群(Fragile-X syndrome)、自閉症系列障礙、帕金森氏症(Parkinson’s disease)及胃食道逆流疾病(GERD)之代謝型麩胺酸受體拮抗劑(負向變構調節劑)。
