A compound represented by the formula: (wherein, R.sup.1 and R.sup.2 are the same or different and each represents a hydrogen atom, hydrocarbon group or heterocyclic group, or R.sup.1 and R.sup.2 may form, together with the adjacent carbon atom, a 3-8 membered iso- or heterocyclic group, R.sup.3 represents a cyclic group, a hydroxy group, a mercapto group that may have oxo, or an amino group, R.sup.4 represents a hydrogen atom, a hydrocarbon group, a hydroxy group, a mercapto group which may have oxo, or an amino group, or R.sup.2 and R.sup.4 may link together to form a double bond, X represents a bond or a linear hydrocarbon group, W represents an oxygen atom or a sulfur atom, ring B represents a 5-8 membered nitrogen-containing heterocyclic group, ring C represents a benzene ring, and represents a single bond or a double bond), or a salt or a prodrug thereof that has excellent neurodegenerative inhibitory activity and brain penetrability, and is useful as an agent for preventing/treating neurodegenerative diseases.