To provide a substance inhibiting the production of TNF-, which is useful as a therapeutic drug for an autoimmune disease such as chronic rheumatoid arthritis.

A new compound having a structure represented by formula [1] or a salt thereof has excellent activity of inhibiting the production of TNF-. In the formula, A represents -(CR5R6)- or -O-; B represents an alkylene group or an alkenylene group; R1, R2, R4, R5 and R6 each represents a hydrogen atom, an alkyl group, an alkenyl group, an adamantylalkyl group or the like; R3 represents an aryl group or an unsaturated heterocycle; and X represents an oxygen atom or a sulfur atom.