The present invention provides a compound represented by the formula ##STR00001## or salts thereof, wherein, Ar.sup.1, Ar, R, R.sup.1, R.sup.2, Ra.sup.1, Ra.sup.2, Ra.sup.3, Ra.sup.4 and Y have meanings described in the specification, having a melanin-concentrating hormone antagonistic, action and useful as an agent for the prophylaxis or treatment of obesity and the like.