Histamine H3 receptor antagonists

Novel compounds which interact with the histamine H3 receptor are defined. These compounds are particularly useful in the treatment of a variety of diseases or conditions in which histamine H3 interactions are beneficial. Thus, the compounds may find use, e.g., in the treatment of diseases of the central nervous system, the peripheral nervous system, the cardiovascular system, the pulmonary system, the gastrointestinal system and the endocrinological system. The novel compounds have a core consisting of a 6 membered aromatic ring containing at least one nitrogen atom and two carbon atoms in the ring and, at the remaining positions in the ring, there is either a carbon or a nitrogen atom.