2-(Pyrrolidin-1-yl)ethyl-3,4-dihydroisoquinolin-1(2H)-one derivatives as potent and selective histamine-3 receptor antagonists.

On the basis of the previously reported benzimidazole 1,3'-bipyrrolidine benzamides (1), a new class of 2-(pyrrolidin-1-yl)ethyl-3,4-dihydroisoquinolin-1(2H)-one derivatives (3-50) were synthesized and evaluated as potent H-3 receptor antagonists. In particular, compound 39 exhibited potent in vitro binding and functional activities at the H-3 receptor, good selectivities against other neurotransmitter receptors and ion channels, acceptable pharmacokinetic properties, and a favorable in vivo profile.