Substituted imidazoles, their preparation and use

Disclosed is a novel class of substituted imidazole compounds, pharmaceutical compositions containing them and uses of these compounds in the treatment and/or prevention of diseases and disorders related to the histamine H3 receptor. More particularly, these compounds are useful for the treatment and/or prevention of diseases and disorders in which an interaction with the histamine H3 receptor is beneficial. These imidazoles compounds have the formula I ##STR1##

wherein R¹, R², R³, R⁴, R⁵, R⁶, A, X, Y and Z are as defined in the specification.