The present invention relates to phenylethynyl derivatives of formulawherein R1 is hydrogen, halogen, lower alkyl or lower alkyl substituted by halogen； R2 is hydrogen, lower alkyl, =O, lower alkoxy, phenyl, hydroxy or lower alkyl substituted by hydroxy； X is N, CF or CH； L is －NR3-, -NHC(R3)2-, -O-, -OC(R3)2-, -CR4R4'-； R3 is hydrogen or lower alkyl； R4/R4' are independently from each other hydrogen or lower alkyl； cyc is cycloalkyl or heterocycloalkyl, or is a non-aromatic bicycle selected from 7-oxa-bicyclo[2.2.1]hept-1-yl or bicyclo[2.2.1]hept-1-yl； n is 1, 2 or 3； 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 positive allosteric modulators (PAM) of the metabotropic glutamate receptor subtype 5 (mGluR5). They are useful for the treatment of schizophrenia or cognitive diseases.本發明係關於下式之苯基乙炔基衍生物其中R1 係氫、鹵素、低碳烷基或經鹵素取代之低碳烷基；R2 係氫、低碳烷基、=O、低碳烷氧基、苯基、羥基或經羥基取代之低碳烷基；X 係N、CF或CH；L 係-NR3-、-NHC(R3)2-、-O-、-OC(R3)2-、-CR4R4'-；R3 係氫或低碳烷基；R4/R4' 彼此獨立地為氫或低碳烷基；cyc 係環烷基或雜環烷基，或係選自7-氧雜-二環[2.2.1]庚-1-基或二環[2.2.1]庚-1-基之非芳香二環；n 為1、2或3；或其醫藥上可接受之酸加成鹽、外消旋混合物、或其相應的對映異構體及/或光學異構體及/或其立體異構體。現在已驚訝地發現，通式I之化合物係代謝型麩胺酸受體亞型5(mGluR5)之正向異位調節劑(PAM)。該等化合物可用於治療精神分裂症或認知疾病。
