A compound represented by the formula (1), or a salt thereof (X represents carbonyl group, or sulfonyl group； R 1 represents hydrogen atom, a halogen atom, an alkyl group, an alkanoyl group, cyano group, or carboxyl group； R 2 represents an alkyl group, a cyclic carbon group, or a heterocyclic group； R 3 represents hydrogen atom, or 1 to 3 substituents； R 4 and R 5 represents hydrogen atom, a halogen atom, or an alkyl group； and R 6 represents an alkyl group, or an alkoxy group), which has an mPGES-1 inhibitory action, and is useful as an active ingredient of a medicament for prophylactic and/or therapeutic treatment of inflammation, pain, rheumatism, and the like.
