The invention relates to compounds of the general formula (I), wherein A-A is -CH2-CH2-, -CH2-CH2-CH2-, -CH2-O- or -O-CH2-; x is hydrogen or hydroxy; R1 is aryl or heteroaryl, unsubstituted or substituted by one or more substituents, selected from the group consisting of lower alkyl, lower alkoxy, halogen or trifluoromethyl; R2 is aryl or heteroaryl, unsubstituted or substituted by one or more substituents, selected from the group consisting of lower alkyl, lower alkoxy, halogen or trifluoromethyl, or is lower alkyl, -(CH2)n-cycloalkyl, -(CH2)n-CF3, -(CH2)p-O-lower alkyl, -(CH2)1,2-phenyl, optionally substituted by halogen, lower alkyl, lower alkoxy or trifluoromethyl, or is -(CH2)p-NR'R', wherein R' and R' form together with the N-atom a heterocyclic ring, selected from the group consisting of piperidine, morpholine, thiomorpholine or 1,1-dioxo thiomorpholine; R3, R4 are independently from each other hydrogen, lower alkyl, phenyl or benzyl; R5 is hydrogen, lower alkyl or benzyl; R6 is hydrogen or lower alkyl; n is 0, 1 or 2; and p is 2 or 3; and to pharmaceutically acceptable acid addition salts thereof for the treatment of psychoses, pain, neurodegenerative disfunction in memory and learning, schizophrenia, dementia and other diseases in which cognitive processes are impaired, such as attention deficit disorders or Alzheimer's disease.
Triaza-spiropiperidine