Disclosed is a compound of formula (I) and its method of synthesis, which is useful as a pharmaceutical in the treatment / prevention of diseases modulated by H3 receptors. Specific examples of the compound of formula (I) include 2-[4-((2S,3'S)-2-methyl-[1,3']bipyrrolidinyl-1'-yl)-phenyl]-1-oxo-2,9-diazaspiro[5.5]undecane-9-carboxylic acid tert-butyl ester and 3-[2-fluoro-4-((2S,3'S)-2-methyl-[1,3']bipyrrolidinyl-1'-yl)-phenyl]-2,9-diazaspiro[5.5]undecan-1-one. Such diseases include cognitive impairment associated with schizophrenia (CIAS), anxiety disorders such as generalized anxiety, panic disorder and post-traumatic stress disorder, major depressive disorder, dementia of Alzheimer type (OAT), cognitive deficits related to neurological diseases chosen from Alzheimer, Parkinson or Huntington, age related cognitive impairment, mild cognitive impairment, vascular dementia, Lewis Body dementia, cognition associated with cognitive deficits, sleep related disorders, attention deficit hyperactivity disorder and depression, and obesity.
