title: Synthesis and preliminary biological studies of 4- and 5-[2-hydroxy-3-(isopropylamino)propoxy]benzimidazoles: selective beta2 adrenergic blocking agents.
abstract: Benzimidazoles carrying the 2-hydroxy-3-(isopropylamino)propoxy side chain at either the C-4 or C-5 ring positions were synthesized and investigated for beta-adrenergic blocking activity. Both compounds demonstrated beta2 selectivity when evaluated in guinea pig atrial and tracheal preparations. The C-4 isomer was 17 times more selective toward tracheal tissue, and its overall potency was roughly comparable to that of propranolol. beta2 selectivity of the C-5 isomer was minimal, with a potency about one-hundredth that of propranolol.
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000138:chemical synthesis*; D000403:Airway Resistance / Q000187:drug effects; D000818:Animals; D001562:Benzimidazoles / Q000138:chemical synthesis* / Q000494:pharmacology; D006168:Guinea Pigs; D006339:Heart Rate / Q000187:drug effects; D066298:In Vitro Techniques; D008722:Methods; D009200:Myocardial Contraction / Q000187:drug effects
chemical_list: D000319:Adrenergic beta-Antagonists; D001562:Benzimidazoles