The present invention relates to compounds of general formula I wherein R1 is halogen, lower alkyl, lower alkoxy, lower alkyl substituted by halogen, lower alkoxy substituted by halogen or cyano R2 is hydrogen, CF3 or lower alkyl R3 is hydrogen, lower alkyl, lower alkenyl, lower alkinyl, heterocycloalkyl, lower alkyl substitueted by cyano, cyano, benzyl substituted by halogen, 2-oxa-6-aza-spiro[3.3]hept-6-yl or is lower alkoxy substituted by halogen X is -CH2- or -CH2-CH2- or to a pharmaceutically acceptable acid addition salt, to a racemic mixture or to its corresponding enantiomer and/or optical isomers thereof. The compounds may be used for the treatment of schizophrenia, obsessive-compulsive personality disorder, major depression, bipolar disorders, anxiety disorders, normal aging, epilepsy, retinal degeneration, traumatic brain injury, spinal cord injury, post-traumatic stress disorder, panic disorder, Parkinsons disease, dementia, Alzheimers disease, mild cognitive impairment, chemotherapy-induced cognitive dysfunction, Down syndrome, autism spectrum disorders, hearing loss, tinnitus, spinocerebellar ataxia, amyotrophic lateral sclerosis, multiple sclerosis, Huntingtons disease, stroke, radiation therapy, chronic stress, abuse of neuro-active drugs, such as alcohol, opiates, methamphetamine, phencyclidine and cocaine.La présente invention concerne des composés de formule générale I dans laquelle R1 représente halogène, alkyle inférieur, alcoxy inférieur, alkyle inférieur substitué par halogène, alcoxy inférieur substitué par halogène ou cyano R2 représente hydrogène, CF3 ou alkyle inférieur R3 représente hydrogène, alkyle inférieur, alcényle inférieur, alcynyle inférieur, hétérocycloalkyle, alkyle inférieur substitué par cyano, cyano, benzyle substitué par halogène, 2-oxa-6-aza-spiro[3.3]hept-6-yle ou représente alcoxy inférieur substitué par halogène X représente -CH2- ou -CH2-CH2- ou un sel daddition dacide pharmaceutiquement acceptable, un mélange rac
