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Updated: May 17, 2026

Subcutaneous Administration of Muscarinic Antagonists and Triple-Immunostaining of the Levator Auris Longus Muscle in Mice
Published on: September 8, 2011
Tyrosine urea muscarinic acetylcholine receptor antagonists: achiral quaternary ammonium groups
Qi Jin1, Roderick S Davis, Ann M Bullion
1GlaxoSmithKline, 709 Swedeland Road, PO Box 1539, King of Prussia, PA 19406-0939, USA.
Abstract:
Tyrosine ureas had been identified as potent muscarinic receptor antagonists with promising in vivo activity. Controlling the stereochemistry of the chiral quaternary ammonium center had proved to be a serious issue for this series, however. Herein we describe the preparation and SAR of tyrosine urea antagonists containing achiral quaternary ammonium centers. The most successful such moiety was the 2-methylimidazo[2,1-b][1,3]thiazol-7-ium group which yielded highly potent antagonists with long duration of action in an inhaled animal model of bronchoconstriction.
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