This invention relates to compounds which are represented by the general formula [I] ##STR00001## [in which A stands for a group of the following formula [a.sub.o] or [b.sub.0] ##STR00002## Ar.sup.1, Ar.sup.2 and Ar.sup.3 stand for optionally substituted phenyl; k stands for 0 or 1; m, n and s stand for 0, 1 or 2; R.sup.1 stands for hydrogen or optionally substituted lower alkyl; R.sup.2, R.sup.3, R.sup.4 and R.sup.5 either stand for hydrogen or optionally substituted lower alkyl, or R.sup.2 and R.sup.3, or R.sup.4 and R.sup.5 together stand for trimethylene and the like; R.sup.60 stands for hydrogen, alkyl, or the like; R.sup.61 and R.sup.71 either stand for alkyl and the like, or together stand for trimethylene and the like; X stands for carbonyl or methylene; Y stands for nitrogen or methine; and Q.sup.- stands for anion], and the like. The compounds of the invention exhibit selective antagonism to muscarinic M.sub.3 receptors, and therefore are useful as safe and effective agents showing little side effect, for treating diseases of the respiratory, urinary and digestive systems.