The present invention relates to compounds of formula wherein R1, R2, R3, X, Z, Ar, and n are as described in the claims, Ar is phenyl or heteroaryl, selected from the group consisting of 1H-indazole-3yl, pyridine-2-yl, pyridine-3-yl, pyridine-4-yl, pyrimidine-5-yl, 1H-pyrazole-3-yl, 1H-pyrazole-4-yl and 1H-pyrazole-5-yl; or to a pharmaceutically suitable acid addition salt thereof, which may be used for the treatment of depression, anxiety disorders, bipolar disorder, attention deficit hyperactivity disorder (ADHD), stress-related disorders, psychotic disorders, schizophrenia, neurological diseases, Parkinson's disease, neurodegenerative disorders, Alzheimer's disease, epilepsy, migraine, hypertension, substance abuse, metabolic disorders, eating disorders, diabetes, diabetic complications, obesity, dyslipidemia, disorders of energy consumption and assimilation, disorders and malfunction of body temperature homeostasis, disorders of sleep and circadian rhythm, and cardiovascular disorders.