Structure-Activity Relationships of Histamine H1-Receptor Agonists

Significant progress in the development of potent and selective histamine H1-receptor agonists has been achieved since 1990. Optimisation of the class of 2-phenylhistamines has furnished 2-[3- (trifluoromethyl)phenyl]histamine and its Nα-methyl derivative. The discovery of histaprodifen (2-[2-(3,3- diphenylpropyl)-1H-imidazol-4-yl]ethanamine) and the novel lead compound suprahistaprodifen (Nα-2-[(1Himidazol- 4-yl)ethyl]histaprodifen) represents additional milestones in the H1-receptor agonist field.