Relationships between the activity of some H<inf>2</inf>-receptor agonists of histamine and their ab initio molecular electrostatic potential (MEP) and electron density comparison coefficients

From an analysis of the ab initio molecular electrostatic potential (MEP) maps of some H2-receptor agonists of histamine in their essential trans-trans conformations, for both neutral and cationic species, a good relationship between H2-activity data and the MEP minima located at the Nπ nitrogen atom of the imidazole ring is predicted. From these data it appears easy to define a threshold value according to which the H2-agonists may be classified as being strongly or weakly active. While the MEP values appear to be a good parameter for activity prediction, in this case, the comparison of electron densities does not give any additional useful information. © 1988.