1,4-Dioxane, a Suitable Scaffold for the Development of Novel M3 Muscarinic Receptor Antagonists

In this study the modulation of the pharmacological profile from agonist to antagonist was successfully obtained by replacing the methyl group in position 6 of the 1,4-dioxane scaffold of the potent M2/M3 muscarinic agonist 1 with bulkier groups. In particular, the 6,6-diphenyl substitution provided the potent M3 preferring antagonist (±)-17, which in in vivo study proved to be effective in reducing the volume-induced contractions of rat urinary bladder and was devoid of cardiovascular effects.