The present invention relates to ethynyl derivatives of formula Iwherein Y is N or CH； with the proviso that Y can only be CH, if at least on of U, V or W are N； U is N or C-R4； V and W are independently N or CH； with the proviso that only one of U, V or W can be simultaneously nitrogen； R4is hydrogen, methyl or halogen； R1is phenyl or heteroaryl, which are optionally substituted by halogen, lower alkyl or lower alkoxy； R is hydrogen or lower alkyl； R2is hydrogen, lower alkyl, lower alkoxy, CF3or S-lower alkyl； R3/R3’are independently from each other hydrogen, lower alkyl or lower alkoxy； or R3and R3’form together a C3-5-cycloalkyl-, tetrahydrofuran- or an oxetane-ring； 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 been found that the compounds of general formula I are allosteric modulators of the metabotropic glutamate receptor subtype 5 (mGluR5).本發明係關於式I之乙炔基衍生物其中Y係N或CH；前提係若U、V或W中之至少一者係N，則Y僅可為CH；U係N或C-R4；V及W獨立地係N或CH；前提係U、V或W中僅一者可同時為氮；R4係氫、甲基或鹵素；R1係苯基或雜芳基，其視情況由鹵素、低碳烷基或低碳烷氧基取代；R 係氫或低碳烷基；R2係氫、低碳烷基、低碳烷氧基、CF3或S-低碳烷基；R3/R3'彼此獨立地係氫、低碳烷基或低碳烷氧基；或R3與R3'一起形成C3-5-環烷基-、四氫呋喃-或氧雜環丁烷環；或係關於其醫藥上可接受之酸加成鹽、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。已發現，通式I之化合物係代謝型麩胺酸受體亞型5(mGluR5)之異位調節劑。
