Metabotropic glutamate receptor antagonists

The present invention concerns compounds of formula. In a preferable embodiment, X represents O; R1 represents C1-4alkyl; cycloC3-12alkyl or (cycloC3-12alkyl)C1-6alkyl, wherein one or more hydrogen atoms in a C1-6alkyl-moiety or in a cycloC3-12alkyl-moiety optionally may be replaced by C1-6alkyloxy, aryl, halo or thienyl; R2 represents hydrogen; halo; C1-6alkyl or amino; R3 and R4 each independently represent hydrogen or C1-6alkyl; or R2 and R3 may be taken together to form -R2-R3-, which represents a bivalent radical of formula -Z4-CH2-CH2-CH2- or -Z4-CH2-CH2- with Z4 being O or NR11 wherein R11 is C1-6alkyl; and wherein each bivalent radical is optionally substituted with C1-6alkyl; or R3 and R4 may be taken together to form a bivalent radical of formula -CH2-CH2-CH2-CH2-; R5 represents hydrogen; Y represents O; and aryl represents phenyl optionally substituted with halo. The invention also relates to the use of a compound according to the invention as a medicament and in the manufacture of a medicament for treating or preventing glutamate-induced diseases of the central nervous system, as well as formulations comprising such a compound and processes for preparing such a compound.