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, heterocyeloalkyl, 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, Parkinson’s disease, dementia, Alzheimer’s disease, mild cognitive impairment, chemotherapy-induced cognitive dysfunction, Down syndrome, autism spectrum disorders, hearing loss, tinnitus, spinocerebellar ataxia, amyotrophic lateral sclerosis, multiple sclerosis, Huntington’s disease, stroke, radiation therapy, chronic stress, abuse of neuro-active drugs, such as alcohol, opiates, methamphetamine, phencyclidine and cocaine.本發明係關於通式I之化合物其中：R1 為鹵素、低碳數烷基、低碳數烷氧基、經鹵素取代之低碳數烷基、經鹵素取代之低碳數烷氧基或氰基；R2 為氫、CF3或低碳數烷基；R3 為氫、低碳數烷基、低碳數烯基、低碳數炔基、雜環烷基、經氰基取代之低碳數烷基、氰基、經鹵素取代之苄基、2-氧雜-6-氮雜-螺[3.3]庚-6-基或為經鹵素取代之低碳數烷氧基；X為-CH2-或-CH2-CH2-；或關於其醫藥上可接受之酸加成鹽，關於其外消旋混合物或其對應鏡像異構體及/或光學異構體。該等化合物可用於治療精神分裂症、強迫型人格障礙、嚴重抑鬱症、躁鬱症、焦慮症、正常老化、癲癇症、視網膜退化、創傷性腦損傷、脊髓損傷、創傷後壓力症、恐慌症、帕金森氏症(Parkinson’s disease)、癡呆、阿茲海默氏症(Alzheimer’s disease)、輕度認知受損、化學療法誘發之認知功能障礙、唐氏症候群(Down syndrome)、自閉症系列障礙、聽力損失、耳鳴、脊髓小腦共濟失調、肌萎縮性側索硬化症、多發性硬化症、亨丁頓氏症(Huntington’s disease)、中風、放射治療、慢性壓力、神經活性藥物(諸如酒精、鴉片、甲基安非他命(methamphetamine)、苯環己哌啶(phencyclidine)及古柯鹼)濫用。
