New Antihistaminic N-Heterocyclic 4-Piperidinamines. 3. Synthesis and Antihistaminic Activity of N-(4-Piperidinyl)-3H-imidazopyridin-2-amines

Article abstract of DOI:10.1021/jm00150a030

To study the bioisosteric replacement of a 2-pyridyl ring for a phenyl nucleus in astemizole, a series of N-(4-piperidinyl)-3H-imidazo<4,5-b>pyridin-2-amines was synthesised and evaluated.The title compounds were obtained starting from either 8a or 8b by four synthetic methods.The in vivo antihistamine activity was evaluated by the compound 48/80-induced lethality test in rats and the histamine-induced lethality test in guinea pigs after oral and/or subcutaneous administration.Compound 37, the isostere of astemizole, showed the most potent antihistaminic properties in the rat.However, astemizole is superior to 37 as to duration of action and total potency.