Antimuscarinic agents: furan analogs of benzilate esters

The methiodide and ethiodide salts of 5-(dimethylaminomethyl)- and 5-(diethylaminomethyl)-alpha, alpha-diphenylfurfuryl alcohol were prepared, These compounds may be considered as furan analogs of dialkylaminoethyl benzilate alkiodides. The pA2 values of these compounds as antagonists of acetylcholine were determined on rat jejunum preparation. All four compounds were significantly less potent than the analogous ester antimuscarinic lachesine. The furan ring cannot be substituted for the ester moiety of typical antimuscarinics. Possible modes of binding by antagonists to the receptor proposed previously are considered that might account for this less-than-expected antimuscarinic activity.