In order to develop compounds which may be useful in the treatment of
memory and cognitive disorders we have synthesized and tested some 1,3
-oxathiolane derivatives bearing an amidine function instead of the cl
assical ammonium head, with the aim of improving brain penetration. Th
e compounds were tested on peripheral and central models of muscarinic
receptors. The results show that, unlike for other series of muscarin
ic ligands, this modification results in the reduced potency of antago
nists, shifts the activity of agonists toward weak antagonism and does
not introduce any noteworthy subtype selectivity.