Disclosed are compounds having the general formula (I) ##STR00001## as defined herein, the preparation thereof, and the use thereof for the prophylaxis or treatment of any disease involving a dysfunction associated with the orexin 2 receptor such as obesity, appetite or taste disorders including cachexia, anorexia and bulimia, diabetes, metabolic syndromes, vomiting and nausea, depression and anxiety, addictions, mood and behaviour disorders, schizophrenia, sleep disorders, restless legs syndrome, memory learning disorders, sexual and psychosexual dysfunctions, pain, visceral or neuropathic pain, hyperalgesia, allodynia, digestive disorders, irritable bowel syndrome, neuronal degenerescence, ischaemic or haemorrhagic attacks, Cushing's disease, Guillain-Barre syndrome, myotonic dystrophy, urinary incontinence, hyperthyroidism, pituitary function disorders, hypertension or hypotension.