Structure and conformation activity relationships of heterocyclic acetylcholine analogues. X. The inhibitory effect of 3-quinuclidinyl benzilates on cardiac muscarinic receptors.

The tertiary and quaternary enantiomers of 3-quinuclidinyl benzilate (QNB) were tested for atropine-like activity on the electrically stimulated guinea-pig atrium preparation. The (R)-isomers had higher affinity for muscarine-sensitive acetylcholine receptors than their corresponding (S)-analogues.