Abstract: The present invention provides a compound represented by the formula (I) and a salt thereof wherein: ring A is a 5-membered aromatic heterocycle optionally having substituent(s); R1 is a hydrogen atom or a hydrocarbon group optionally having substituent(s); W is an oxygen atom or a sulfur atom; X1 and X2 may be the same or different and each is a hydrogen atom, a hydrocarbon group optionally having substituent(s) or a heterocyclic group, or, X1 and X2 in combination, optionally, form an oxygen atom, a sulfur atom or ?NR2; ring B is an aromatic ring optionally further having substituent(s); Y is a bond, C1-6 alkylene C2-6 alkenylene or C2-6 alkynylene, optionally having substituent(s); and Z is —SOnR3 or —COR4, which are useful as a pharmaceutical agent having GnRH antagonistic action.