Novel phenylacetic acid derivative

A compound represented by the formula (1) or a salt thereof ( --- represents a single bond, or a double bond; R 1 represents hydrogen atom, or an alkyl group; R 2 and R 3 represent hydrogen atom, or an alkyl group; R 4 and R 5 represent hydrogen atom, hydroxy group, an alkoxyl group, a halogen atom, or a mono- or di-alkyl-substituted amino group; R 6 represents hydrogen atom, cyano group, an alkoxycarbonyl group, or carboxy group; R 7 represents one or two of substituents on the benzene ring (the substituents are selected from hydrogen atom, a halogen atom, nitro group, cyano group, hydroxy group, amino group, an alkyl group, and an alkoxyl group); A represents a 5-membered or 6-membered non-aromatic heterocyclic ring containing one or two contiguous sulfur atoms (the sulfur atoms may independently form oxide); W --- represents oxo group, hydrogen atom, an alkyl group, hydroxy group, an alkoxyl group, or a halogen atom; and X represents oxygen atom, or sulfur atom), or a salt thereof, which has a superior suppressing action against prostaglandin E 2 production and is useful as an active ingredient of medicaments with reduced adverse reactions such as gastrointestinal disorders.