Some thio- and the benzoyl-derivatives of deoxamuscarine were synthesized and tested as muscarinic agonists using radioligand binding assays and functional tests. In comparison with deoxamuscarine, used as reference compound, no dimension/distance modification is tolerated for correct lipophilic pocket recognition. The substitution of the ammonium group with a sulphonium group significantly decreased muscarinic potency. The so-called 'muscarinic sub-site' accepts relatively bulky functions as long as it is bound to the cyclopentane carrier by an oxygen bridge. Esterification of this moiety increases the M 2 subtype selectivity, while etherification heightens that of M 3 .