The present invention relates to compounds of the general formula wherein R 1 is hydrogen； R 1 represents hydrogen, lower alkyl, benzyl, lower alkyl substituted hydroxy or represents cycloalkyl, possibly substituted cyano； or R and R form together with the nitrogen atom to which they are attached a heterocycloalkyl group, optionally containing an additional ring atom of N, O or S and possibly substituted by hydroxy； R 1 represents halogen, phenyl optionally substituted with one or more halogen, cyano, lower alkyl substituted by halogen, lower alkoxy substituted by halogen or lower alkyl substituted by hydroxy, or represents heteroaryl, optionally substituted by lower alkyl or halogen, or represents 3, 6-dihydropyran-4-yl, or is piperidin-1-yl, optionally substituted with one or more halogen； or their pharmaceutically acceptable acid addition salts, racemic mixtures, or their corresponding enantiomers and / or optical isomers. The compounds of formula I can be used to treat schizophrenia, obsessive-compulsive personality disorder, major depression, bipolar disorder, anxiety disorders, normal aging, epilepsy, retinal degeneration, traumatic brain injury, spinal cord injuries, post-traumatic stress, panic disorder, Parkinson's disease, dementia, Alzheimer's disease, cognitive impairment caused by chemotherapy for cognitive dysfunction, Down syndrome, autism spectrum disorders, hearing loss, noise in check, spinocerebellar ataxia, amyotrophic lateral sclerosis, multiple sclerosis, diseaseНастоящее изобретение относится к соединениям общей формулыгде Rпредставляет собой водород； Rпредставляет собой водород, низший алкил, бензил, низший алкил замещенный гидрокси или представляет собой циклоалкил, возможно замещенный циано； или Rи Rобразуют вместе с атомом азота, к которому они присоединены гетероциклоалкильную группу, возможно содержащую дополнительный кольцевой атом N, О или S и возможно замещенную гидрокси； Rпредставляет собой галоген, фенил, возможно замещенный одним и
