The present invention relates to novel compounds of the following formula, where the dotted line designates an optional bond: ##STR1## wherein "het" designates a five membered heterocyclic ring which may include 1 or 2 double bonds and 1-4 heteroatoms selected from nitrogen, oxygen or sulphur, provided that "het" may not designate a 1,2,4- or 1,3,4-oxadiazole; R.sup.1 -R.sup.5 are as defined in the specification;as well as individual stereo isomers and pharmaceutically acceptable acid addition salts thereof.The invention moreover relates to methods for the preparation of the compounds of formula I, to novel intermediates, to pharmaceutical compositions containing same and to methods for the treatment of disorders, caused by malfunction of the acetylcholine (AcCh) or muscarinic system, by administering a non-toxic effective amount of a compound of formula I.