A compound of the formula: ##STR1## wherein Ar.sup.1 and Ar.sup.2 independently represent an optionally substituted aromatic group; P and Q independently represent a divalent aliphatic hydrocarbon group having at least 2 carbon atoms and optionally having either oxygen or sulfur in the carbon chain; R.sup.1 and R.sup.3 independently represent --CO--R, --CONH--R (R represents a hydrocarbon group or a heterocyclic group) or a hydrocarbon group; R.sup.2 and R.sup.4 independently represent hydrogen or an alkyl group; R.sup.2 and R.sup.4 independently represent hydrogen or an alkyl group; R.sup.1 and R.sup.2 or R.sup.3 and R.sup.4, taken together with the adjacent nitrogen atom, may form a nitrogen-containing heterocyclic group; and j represents 0 or 1, or a salt thereof, has excellent GnRH-receptor antagonizing activity and is useful as a prophylactic and therapeutic agent for hormone-dependent and other diseases.