The present invention relates to novel compounds of the following formula: ##STR1## individual isomers and pharmaceutically acceptable acid addition salts thereof, whereinR.sup.1 is hydrogen, alkyl or phenyl-lower alkyl, in which the phenyl group may be substituted with halogen, lower alkyl or lower alkoxy;R.sup.2 is alkyl, alkenyl, alkynyl, branched or unbranched, with 1-6 carbon atoms inclusive, which group may be optionally substituted with fluoro, hydroxy or phenyl optionally substituted with halogen, trifluoromethyl, lower alkyl, hydroxy or lower alkoxy;R.sup.3 and R.sup.4 are the same or different, and each represents hydrogen, alkyl(1-6 C-atoms), cycloalkyl (3-6 C-atoms), phenyl optionally substituted with halogen trifluoromethyl, lower alkyl, hydroxy or lower alkoxy, or phenyl-lower alkyl, in which the phenyl group may be substituted with halogen, trifluoromethyl, lower alkyl, hydroxy or lower alkoxy.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.