2-(4,5-Dihydroimidazol-2-yl)benzimidazoles as highly selective imidazoline I2/adrenergic α2 receptor ligands Original Research Article

2-(4,5-Dihydroimidazol-2-yl)benzimidazoles have been identified as selective imidazoline I2/α2-adrenoceptor ligands. 4-Methyl (2) and 4-chloro (4) derivatives display I2 affinity at nanomolar concentration (Ki = 4.4 and 17.7 nM, respectively) and high I2/α2 selectivity ratio = 4226 and 5649, respectively. An evidence has been obtained that pKa value influences considerably the I2/α2-selectivity ratio of this class of imidazoline I2 receptor ligands.