This invention provides the compounds of formula (I), or a pharmaceutically acceptable salt thereof, wherein R.sup.1 and R.sup.2 independently represent hydrogen or the like; R.sup.3 and R.sup.4 independently represents hydrogen or the like; R.sup.5 represents aryl or the like; --X--Y-- represents --CH.sub.2O-- or the like; and n represents 0, 1 or 2. These compounds have ORL1-receptor antagonist activity; and therefore, are useful to treat diseases or conditions such as pain, various CNS diseases etc.