The present invention relates to small molecule potentiators of metabotropic receptors, in particular of the mGlu2 receptor. The present invention also relates to the use of these compounds for the prevention or treatment of neurological and psychiatric disorders associated with glutamate dysfunction and diseases in which metabotropic glutamate receptors are involved. The present invention thus provides compounds of formula I wherein X1 is N or C—R1, X2 is N or C—R2, X3 is N or C—R3, X4 is N or C—R4 provided that none or one of X1, X2, X3 or X4 is N; Y1 is N, C or C—R5, Y2 is N, C or C—R6, Y3 is Y1, Y2, N, C or C—R7, Y4 is N, C or C—R8 provided that only the moiety Y1, Y2, Y3 or Y4 to which Z is bound is C and further provided at most one of Y1, Y2, Y3 or Y4 is N; Z is O, S, S(O), S(O)2 or NRZ; Q is CH2 or CH2CH2, where one or two of the hydrogen atoms in CH2 or CH2CH2 may be replaced by halogen, C1-C4-alkyl or C1-C4-haloalkyl; R1 is inter alia hydrogen, halogen, C1-C6-alkyl, C1-C6-haloalkyl, C1-C6-alkoxy, C1-C4-haloalkoxy, C3-C8-cycloalkyl, a radical NR1aR1b, C-bound 3- to 7-membered, saturated heterocyclyl having 1 or 2 nitrogen atoms and 0 or 1 heteroatoms, selected from O and S, as ring members, aryl, aryl-CH2, aryloxy, hetaryl, hetaryloxy or hetaryl-CH2, wherein the heterocyclyl, aryl and hetaryl rings ring in the last six radicals themselves are unsubstituted or carry 1, 2, 3, 4 or 5 identical or different radicals R1c; R2 has one of the meanings given for R1; R3 and R4 are, inter alia, selected from hydrogen, halogen, C1-C4-alkyl, C1-C4-haloalkyl, C3-C6-cycloalkyl, C1-C4-alkoxy, C1-C4-alkoxy-C1-C4-alkyl, phenyl, C1-C4-haloalkoxy, a radical (CH2)nNR′R″; R5, R6, R7, R8 are, independently of each other, selected from hydrogen, halogen, etc.; Ra is C3-C6-cycloalkyl, C1-C6-haloalkyl or C1-C6-alkyl, which is unsubstituted or carries one radical selected from C1-C4-alkoxy, C1-C4-haloalkoxy and a radical NRa1Ra2; and the N-oxides and the pharmaceutically acceptable salts thereof.
Small molecule potentiators of metabotropic glutamate receptors